Artificial Intelligence Has Just Found Two Exoplanets: What Does This Mean For Planet Hunting?

There are now two known eight-planet solar systems in the galaxy. Artificial intelligence was used to comb through the data collected three years ago by the Kepler Space Telescope and its algorithms helped find Kepler 90-1, the eight planet in that solar system.  (NASA)

By Elizabeth Tasker

The media was abuzz last week with the latest NASA news conference. A neural network — a form of artificial intelligence or machine learning — developed at Google had found two planets in data previously collected by NASA’s prolific Kepler Space Telescope. It’s a technique that could ultimately track-down our most Earth-like planets.

The new exoplanets orbit stars already known to host planetary systems, Kepler-90 and Kepler-80. While both are only slightly larger than the Earth, their two-week orbits makes these worlds too hot to be considered likely candidates for hosting life. Moreover, the systems are thousands of light years away, putting the planets out of range of atmospheric studies that could test their habitability.

With over 3,500 exoplanets already discovered, you might be forgiven for finding these additions underwhelming. However, while other planets in the same system have been known about for several years, these two Earth-sized worlds were previously overlooked. The difference is not a new telescope, but an exploration of the data with a different kind of brain.

The Kepler Space Telescope searches for planets using the transit technique; detecting small dips in amount of starlight as the planet passes in front of the star. As planets are much smaller than stars, picking out this tiny light drop is a tricky task. For a Jupiter-sized planet orbiting a star like our Sun, the decrease in brightness is only about 1%. For an Earth-sized planet, the signal becomes so small it is right on the edge of what Kepler is able to detect. This makes their dim wink extremely difficult to spot in the data.

Kepler Space Telescope collected data on planet transits around distant stars for four years, and the information has provided  — and will continue providing —  a goldmine for planet hunters.  A severe malfunction in 2013 had robbed Kepler of its ability to stay pointed at a target without drifting off course, but the spacecraft was stabilized and readjusted to observe a different set of stars.  (NASA)

The discovery paper published in the Astronomical Journal combined the expertise of Christopher Shallue from Google’s artificial intelligence project, Google Brain, and Andrew Vanderburg, a NASA Sagan Postdoctoral Fellow and astronomer at the University of Texas at Austin. The researchers explored using a neural network to shake ever harder to find worlds out of the Kepler data.

It is a technique that is being used across a wide range of disciplines, but what exactly does a neural network do?

Neural networks are computer algorithms inspired by the way the brain recognizes patterns. For example, as a child you learned to recognize buses. It is unlikely anyone sat you down and presented a set of rules for identifying a bus. Rather, buses were repeatedly pointed out to you on the street and your brain found its own set of similarities within these examples. The idea behind a neural network is similar. Rather than telling a computer how to identify a feature such as the dip in light from a planet, the network is fed many examples and allowed to determine the features to get a consistently correct result.

This is a very successful way of developing pattern recognition software, making neural networks one of the newest tools in town used from image recognition to stock market trends. A key strength is dealing with large quantities of data to produce a consistent result.

Kepler has observed about 200,000 stars and another 200,000 will be the target for the Transiting Exoplanet Survey Satellite (TESS) to be launched next year. And if that analysis still looks doable with a bit of elbow grease, the NASA exoplanet archive has just added 18 million light curves from the UKIRT Microlensing survey.

In addition to being slow, humans can also be inconsistent (I once tried to flag down a lorry instead of a bus before I’d had my morning tea). This is especially true when trying to tease out the faint signature of Earth-sized worlds at the limit of the telescope’s capabilities. While Kepler has an automated pipeline to identify likely planets, simulated data suggests it recovers just 26% of Earth-sized planets on orbits similar to our own. Exploring new ways to handle these huge data sets is therefore a top priority.

While neural networks all learn to identify patterns from a series of examples, there are different choices for their structure. In their discovery paper, Shallue and Vanderburg try three different network architectures. The one they find the most successful is known as a “Convolution Neural Network”, which is commonly used in image classification.

Neural networks are loosely inspired by the structure of the human brain: “Neurons” do a simple computation and then pass information to the next layer of neurons. In this way, a computer can “learn” to identify a dog in an image, or an exoplanet in a Kepler light curve.  (Google)

This utilizes the fact that neighboring data points may form related structures, examining attributes such as the maximum and minimum of small local groups of points to hunt for features. This makes sense when your input data is the light from a star being consecutively dimmed by the passage of a planet.

In this first exploration, the neural network searched for undiscovered planets in known systems. The network found a total of 30 possible new planets, four of which it assigned a probability greater than 0.9 of this being a true detection. Based on the network’s performance when tested on known planets, this level of probability corresponded to a correctly identified planet 96% of the time.

These four candidates were then examined by Shallue and Vanderburg for alternative reasons for the dip in the light curve. Such false positives can be caused by the star being part of a binary system, where the stellar siblings periodically eclipse one another to produce small drops in their combined light. One candidate fell foul of having a close stellar neighbor which may have been causing this effect, while a second candidate showed a light dip that increased over time; an effect not expected by a planet. For the remaining two possibilities, there were no obvious reservations. These were really two new planets; Kepler-90i and Kepler-80g.

While neither new exoplanet is likely to be Earth-like, both belong to intriguing planetary systems. Kepler-80g is the outermost world of a compact system of six planets, all with orbits between 1 – 10 days. The outer five planets form a “resonant chain”; a musical-sounding term that means that the duration of the orbits of neighboring planets are neat integer ratios (in this case, either 2:3 or 3:4).

This orderly line-up is seen in the orbits of the Jovian moons, Io, Europa and Ganymede, and more recently, in the TRAPPIST-1 exoplanet system that hit the headlines last February. Computer models suggest that resonant orbits are formed when planets migrate inwards from a location further out from their star. This is likely how such a close stack of planets exists so close to the star, where we do not expect a lot of planet-building dust and gas.

The second planet hit the media headlines because its addition made Kepler-90 the first known star other than our own Sun to host eight planets. Also like our Solar System, the Kepler-90 planets have the giant gaseous worlds further from the star and the smaller rocky planets closer in. However, these planets all sit within the orbit of the Earth around the Sun, suggested that they too migrated inwards from colder reaches where ice could solidify and help build-up the mass of the giant planets.

Kepler-90i is 2,545 light-years away from Earth and orbits its host star in 14.45 days. (NASA)

Notably, Kepler-90i is right at the limit of what Kepler is sensitive enough to detect. This means the system may well have more planets that are too small and distant from their star for Kepler to spot.

In addition to finding these small planets, the size of their planetary systems underscores the potential of the neural network. The evolution of a planet depends heavily on its neighbors. The Earth may have been a dry world if our gas giants had not swept in icy meteorites to deliver oceans to our surface. Mars’s build-up of ice changes substantially over time as the planet’s axis wobbles due to the looming presence of Jupiter.

Such conditions can be modeled, but only if the full planetary system is known. Uncovering the planets around known host stars helps constrain models of how planets form and evolve, and even hint at which worlds may have remained temperate enough to develop life. Picking out the smaller worlds in a starlight signature crowded by other planets is as tricky as spotting a bus in the morning rush hour before tea; it could need this computer algorithm on the job.

Last week’s announcement may show the beginning of a new regime of planet hunting; one where we shake-out the smaller worlds hidden in noisy data. This could provide us both with more small planets and many more multi-planet systems, helping us pin down the most likely places we may find another planet like our own or even one most likely to be completely alien.

Elizabeth Tasker is a planetary scientist at the Japanese space agency JAXA and the Earth-Life Science Institute in Tokyo.  Her newly-released book is titled “The Planet Factory.”

The Very Influential Natalie Batalha

Natalie Batalha, project scientist for the Kepler mission and a leader of NASA’s NExSS initiative on exoplanets, was just selected as one of Time Magazine’s 100 most influential people in the world. (NASA, TIME Magazine.)

I’d like to make a slight detour and talk not about the science of exoplanets and astrobiology, but rather a particular exoplanet scientist who I’ve had the pleasure to work with.

The scientist is Natalie Batalha, who has been lead scientist for NASA’s landmark Kepler Space Telescope mission since soon after it launched in 2009, has serves on numerous top NASA panels and boards, and who is one of the scientists who guides the direction of this Many Worlds column.

Last week, Batalha was named by TIME Magazine as one of the 100 most influential people in the world. This is a subjective (non-scientific) calculation for sure, but it nonetheless seems appropriate to me and to doubtless many others.

Batalha and the Kepler team have identified more than 2500 exoplanets in one small section of the distant sky, with several thousand more candidates awaiting confirmation.  Their work has once and for all nailed the fact that there are billions and billions of exoplanets out there.

“NASA is incredibly proud of Natalie,” said Paul Hertz, astrophysics division director at NASA headquarters, after the Time selection was announced.

“Her leadership on the Kepler mission and the study of exoplanets is helping to shape the quest to discover habitable exoplanets and search for life beyond the solar system. It’s wonderful to see her recognized for the influence she has had on the world – and on the way we see ourselves in the universe.”

And William Borucki, who had the initial idea for the Kepler mission and worked for decades to get it approved and then to manage it, had this to say about Batalha:

“She has made major contributions to the Kepler Mission throughout its development and operation. Natalie’s collaborative leadership style, and expert knowledge of the population of exoplanets in the galaxy, will provide guidance for the development of successor missions that will tell us more about the habitability of the planets orbiting nearby stars.”

Batalha has led the science mission of the Kepler Space Telescope since it launched in 2009. (NASA)

As a sign of the perceived importance of exoplanet research, two of the other TIME influential 100 are discoverers of specific new worlds.  They are Guillem Anglada-Escudé (who led a team that detected a planet orbiting Proxima Centauri) and Michael Gillon (whose team identified the potentially habitable planets around the Trappist-1 system.)

But Batalha, and no doubt the other two scientists, stress that they are part of a team and that the work they do is inherently collaborative. It absolutely requires that many others also do difficult jobs well.

For Batalha, working in that kind of environment is a natural fit with her personality and skills.  Having watched her at work many times, I can attest to her ability to be a strong leader with extremely high standards, while also being a kind of force for calm and inclusiveness.

We worked together quite a bit on the establishing and running of this column, which is part of the NASA Nexus for Exoplanet System Science (NExSS) initiative to encourage interdisciplinary thinking and collaboration in exoplanet science.

It was NASA’s astrobiology senior scientist Mary Voytek who set up the initiative and saw fit to start this column, and it was Batalha (along with several others) who helped guide and focus it in its early days.

I think back to her patience.  I was visiting her at NASA’s Ames Research Center in Silicon Valley and talking shop — meaning stars and planets and atmospheres and the like.  While I had done a lot of science reporting by that time, astronomy was not a strong point (yet.)

So in conversation she made a reference to stars on the Hertzsprung-Russell diagram and I must have had a somewhat blank look to me.  She asked if I was familiar with Hertzsprung-Russell and I had to confess that I was not.

Not missing a beat, she then went into an explanation of what is a basic feature of astronomy, and did it without a hint of impatience.  She just wanted me to know what the diagram was and what it meant, and pushed ahead with good cheer to bring me up to speed — as I’m sure she has done many other times with many people of different levels of exposure to the logic and complexities of her very complex work.

(Incidently, the Hertzsprung-Russell diagram plots each star on a graph measuring the star’s brightness against its temperature or color.)

I mention this because part of Batalha’s influence has to do with her ability to communicate with individuals and audiences from the lay to the most scientifically sophisticated.  Not surprisingly, she is often invited to be a speaker and I recommend catching her at the podium if you can.

By chance — or was it chance? — the three exoplanet scientists selected for the Time 100 were at Yuri Milner’s Breakthrough Discuss session Thursday when the news came out. On the left is Anglada-Escude, Batalha in the middle and Gillon on the right.

Batalha was born in Northern California with absolutely no intention of being a scientist.  Her idea of a scientist, in fact, was a guy in a white lab coat pouring chemicals into a beaker.

As a young woman, she was an undergrad at the University of California at Berkeley and planned on going into business.  But she had always been very good and advanced in math, and so she toyed with other paths.  Then, one day, astronaut Rhea Setton came to her sorority.  Setton had been a member of the same sorority and came to deliver a sorority pin she had taken up with during on a flight on the Space Shuttle.

“That visit changed my path,” Batalha told me.  “When I had that opportunity to see a woman astronaut, to see that working for NASA was a possibility, I decided to switch my major — from business to physics.”

After getting her BA in physics from UC Berkeley, she continued in the field and earned a PhD in astrophysics from  UC Santa Cruz. Batalha started her career as a stellar spectroscopist studying young, sun-like stars. Her studies took her to Brazil, Chile and, in 1995, Italy, where she was present at the scientific conference when the world learned of the first planet orbiting another star like our sun — 51 Pegasi b.

It had quite an impact.  Four years later, after a discussion with Kepler principal investigator Borucki at Ames about challenges that star spots present in distinguishing signals from transiting planets, she was hired to join the Kepler team.  She has been working on the Kepler mission ever since.

Asked how she would like to use her now publicly acknowledged “influence,” she returned to her work on the search for  habitable planets, and potentially life, beyond earth.

“We’ve seen that there’s such a keen public interest and an enormous scientific interest in terms of habitable worlds, and we have to keep that going,” she said. “This is a very hard problem to solve, and we need all hands on deck.”

She said the effort has to be interdisciplinary and international to succeed, and she pointed to the two other time 100 exoplanet hunters selected.  One is from Belgium and the other is working in the United Kingdom, but comes from Spain.

When the nominal Kepler mission formally winds down in September, she says she looks forward to more actively engaging with the exoplanet science Kepler has made possible.

The small planets identified by Kepler as one one year ago that are small and orbit in the region around their star where water can exist as a liquid. NASA Ames/N. Batalha and W. Stenzel

Batalha’s role in the NASA NExSS initiative offers a window into what makes her a leader — she excels at making things happen.

Voytek and Shawn Domogal-Goldman of Goddard founded and oversee the group.  They then chose Batalha two other leaders (Anthony Del Genio of the Goddard Institute for Space Studies and Dawn Gelino of NASA Exoplanet Science Institute ) to be the hands-on leaders of the 18 groups of scientists from a wide variety of American universities.

(Asked why she selected Batalha, Voytek replied, “TIME is recognizing what motivated us to select her as one of the leaders for….NExSS. Her scientific and leadership excellence.”)

This is the official NExSS task:  “Teams will help classify the diversity of worlds being discovered, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Scientists are developing ways to identify habitable environments on these worlds and search for biosignatures, or signs of life.  Central to the work of NExSS is understanding how biology interacts with the atmosphere, surface, oceans, and interior of a planet, and how these interactions are affected by the host star.”

She has encouraged and helped create the kinds of collaborations that these tasks have made essential, but also helped identify upcoming problems and opportunities for exoplanet research and has started working on ways to address them.  For instance, it became clear within the NExSS group and larger community  that many, if not most exoplanet researchers would not be able to effectively apply for time to use the James Webb Space Telescope (JWST) for several years after it launched in late 2018.

To be awarded time on the telescope, researchers have to write detailed descriptions of what they plan to do and how they will do it. But how the giant telescope will operate in space is not entirely know — especially as relates to exoplanets.  So it will be impossible for most researchers to make proposals and win time until JWST is already in space for at least two of its five years of operation.

Led by Batalha, exoplanet scientists are now hashing out a short list of JWST targets that the community as a whole can agree should be the top priorities scientifically and to allow researchers to learn better how JWST works.  As a result, they would be able to propose their own targets for research much more quickly  in those early years of JWST operations.   It’s the kind of community consensus building that Batalha is known for.

She also has an important roles in the NASA Astrophysics Advisory Committee and hopes to use the skills she developed working with Kepler on the upcoming Transiting Exoplanet Survey Satellite (TESS) mission.

Batalha preparing for the Science Walk in San Francisco on Earth Day.

A mother of four (including daughter Natasha, who is on her way to also becoming an accomplished astrophysicist), Batalha is active on Facebook sharing her activities, her often poetic thoughts, and her strong views about scientific and other issues of the day.

She was an active participant, for instance, in the National March for Science in San Francisco, posting photos and impressions along the way.  I think it’s fair to say her presence was noticed with appreciation by others.

And that returns us to what she considers to be some of her greatest potential “influence” — being an accomplished, high ranking and high profile NASA female scientist.

“I don’t have to stand up and say to young women ‘You can do this.’  You can just exist doing your work and you become a role model.  Like Rhea Setton did with me.”

And it is probably no coincidence that four other senior (and demanding) positions on the Kepler mission are filled by women — two of whom were students in classes taught some years ago by Natalie Batalha.

Some Spectacular Images (And Science) From The Year Past

A rose made of galaxies

This is a golden era for space and planetary science, a time when discoveries, new understandings, and newly-found mysteries are flooding in.  There are so many reasons to find the drama intriguing:  a desire to understand the physical forces at play, to learn how those forces led to the formation of Earth and ultimately us, to explore whether parallel scenarios unfolded on planets far away, and to see how our burgeoning knowledge might set the stage for exploration.

But always there is also the beauty; the gaudy, the stimulating, the overpowering spectacle of it all.

Here is a small sample of what came in during 2016:

The Small Magellanic Cloud, a dwarf galaxy that is a satellite of our Milky Way galaxy, can be seen only in the southern hemisphere.  Here, the Hubble Space Telescope captured two nebulas in the cloud. Intense radiation from the brilliant central stars is heating hydrogen in each of the nebulas, causing them to glow red.

Together, the nebulas are called NGC 248 and are 60 light-years long and 20 light-years wide. It is among a number of glowing hydrogen nebulas in the dwarf satellite galaxy, which is found approximately 200,000 light-years away.

The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE). Astronomers are using Hubble to probe the Milky Way satellite to understand how dust is different in galaxies that have a far lower supply of heavy elements needed to create that dust.  {NASA.ESA, STSci/K. Sandstrom (University of California, San Diego), and the SMIDGE team}

This picture combines a view of the southern skies over the ESO 3.6-metre telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left) from the NASA/ESA Hubble Space Telescope. Proxima Centauri is the closest star to the Solar System and is orbited by the planet Proxima b, which was discovered using the HARPS instrument on the ESO 3.6-metre telescope.

Probably the biggest exoplanet news of the year, and one of the major science stories, involved the discovery of an exoplanet orbiting Proxima Centauri, the star closest to our own.

This picture combines a view of the southern skies over the European Space Observatory’s 3.6-metre telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left).

The planet Proxima Centauri b is thought to lie within the habitable zone of its star.  Learning more about the planet, the parent star and the two other stars in the Centauri system has become a focus of the exoplanet community.

We all know about auroras that light up our far northern skies, but there’s no reason why they wouldn’t exist on other planets shielded by a magnetic field — such as Jupiter.  Astronomers using the Hubble Space Telescope have found them on the poles of our solar system’s  largest planet, and produced far ultraviolet light images taken as the Juno spacecraft approached the planet.

Auroras are formed when charged particles in the space surrounding the planet are accelerated to high energies along the planet’s magnetic field. When the particles hit the atmosphere near the magnetic poles, they cause it to glow like gases in a fluorescent light fixture. Jupiter’s magnetosphere is 20,000 times stronger than that of Earth.

The full-color disk of Jupiter in this image was separately photographed at a different time by Hubble’s Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project that annually captures global maps of the outer planets.

Inside the Crab Nebula

Peering deep into the core of the Crab Nebula, this close-up image reveals the heart of one of the most historic and intensively studied remnants of a supernova, an exploding star. The inner region sends out clock-like pulses of radiation and tsunamis of charged particles embedded in magnetic fields.

The NASA Hubble Space Telescope image is centered on the region around the neutron star (the rightmost of the two bright stars near the center of this image) and the expanding debris surrounding it. Intricate details of glowing gas are shown in red and the blue glow is radiation given off by electrons spiraling at nearly the speed of light in the powerful magnetic field around the crushed stellar core.

The Gemini Planet Imager provides some of the earliest high-resolution, high-contrast direct imaging of exoplanets.  Using a coronagraph inside the telescope to block out the light of the star, the GPI can then allow researchers to see the region surrounding that star — in other words, where exoplanets might be.

This image includes a wide-angle view of the star HD 106906 taken by the Hubble Space Telescope and a close-up view from the Planet Imager, which operates on the Gemini South telescope in Chile’s Atacama Desert.  The image reveals a disturbed system of comets near the star, which may be responsible for the orbit of the the unusually distant giant planet (upper right).

The GPI Exoplanet Survey is operated by a team of astronomers from the University of California at  Berkeley and 23 other institutions, and is targeting 600 young stars to understand how planetary systems evolve over time.

Paul Kalas of UC Berkeley is responsible for the image and led the team that wrote about it. That paper actually came out in the Astrophysical Journal in late 2015 but, hey, that’s almost 2016.

Astronomers have regularly found a galaxy or star that is the furthest from us ever to be detected.  But the record is there to be broken, and in 2016 it was astronomers from the Great Observatories Origins Deep Survey (GOODS) who made the discovery.

Galaxy GN-z11, shown in the inset, was imaged as it was 13.4 billion years in the past, just 400 million years after the big bang.  That means the universe was only three percent of its current age when the light left that galaxy.

The galaxy has many blue stars that are bright and young, but it looks red in this image because its light has been stretched to longer spectral wavelengths by the expansion of the universe.

(NASA, ESA, P. Oesch (Yale University), G. Brammer ( STScI)), P. van Dokkum (Yale University), and G. Illingworth (University of California, Santa Cruz)

Biggest announce of discovred exoplanets by Kepler. (No, those are not real images, but still...)

No, these are not images of actual exoplanets, but they represent the continuing work of one of NASA’s most pioneering and productive missions, the Kepler Space Telescope. In May the Kepler team announced the detection of 1284 more planets or planet candidates as part of its newest catalog, the largest number announced at once in the mission.

To date, Kepler has identified unconfirmed 4,696 planet candidates, 2,331 confirmed planets, and 21 confirmed small planets in a habitable zone. In addition, the follow-on K2 mission has identified 458 candidate planets and 173 confirmed.

The Kepler spacecraft stared fixedly at a small portion of the sky for four years, looking to identify miniscule dimmings in the brightness of stars that would indicate that a planet was passing between the telescope and the star. In this way, Kepler has established a census of exoplanets that has been extrapolated to show the presence of billions and billions of planets around other stars.

The 21-foot array that will collect photons for the James Webb Space Telescope was finished and put on display in November at the Goddard Space Flight Center. It will be the largest mirror to go into space, and will likely make the JWST into the most powerful and far-seeing observatory ever.

It will observe in the infrared portion of the spectrum because its goals include peering deep into the past of the universe, which is now most visible in the infrared. This means the JWST will have to be cooled to -364 degrees F, just 50 degrees above absolute zero.  To achieve that temperature, it’s insulated from the sun by five membrane layers, each no thicker than a human hair. Placing those membranes was finished in November, marking an end to construction of the telescope “mirror.”

The project has been enormously ambitious, and with that has come long delays and budget overruns that almost resulted in it being scrapped. Just this month, some early vibrating tests – designed to simulate launch conditions – experienced an anomaly that NASA engineers are working on now.  The JWST is scheduled to launch in late 2018.

This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter.

While the plumes spitting out of Saturn’s moon Enceladus are much better known now — the Cassini spacecraft flew through them in 2015, after all — the growing scientific consensus that Europa also has some plumes may be of even greater importance.  That moon is much larger, its ice-covered oceans have been determined to hold more water than all the oceans of Earth, and those oceans have clearly been around for a long time.

Hubble’s ultraviolet sensitivity allowed for the detection of the plumes, which rise more than 100 miles above Europa’s icy surface. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions. (NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center.)

compounds being created in the xxx nebula

How the fundamentals needed for life are created in space has been a longstanding mystery.  The cosmos, after all, began with hydrogen and helium, and that was about it.  But life needs carbon atoms connected to hydrogen, oxygen, nitrogen and other elements

Astronomers and astrochemists have been making progress in recent years and now understand the basics of how the heavier elements are formed in space.  New data from the European Space Agency’s Herschel Space Observatory has gone further and has established that ultraviolet light from stars plays a key role in creating these molecules.  Previously, scientists thought that turbulence created by “shock” events was the driving force.

This image is of the Orion nebula, where scientists studied carbon chemistry of a major star-forming region. Herschel probed an area of the electromagnetic spectrum — the far infrared, associated with cold objects — that no other space telescope has reached before so it could take into account the entire Orion Nebula instead of individual stars.

The result was a better understanding of how carbon and hydrogen reach the states necessary to bond and form the basic carbon chemistry of the cosmos (and of life.)

Within the inset image, the emission from ionized carbon atoms (C+), overlaid in yellow, was isolated and mapped out from spectrographic data.

Following a successful close flyby of Enceladus, the NASA-ESA Cassini spacecraft captured this image of the moon with Saturn’s rings beyond.

The image was taken in visible light with the Cassini spacecraft wide-angle camera when it was about 106,000 miles away from Enceladus. That flyby turned into a fly-through as well, when Cassini entered the plumes of water vapor and dust that shoot out of the bottom of the moon.

Scientists already know that an array of organic and other chemicals are in the plumes, but the field is awaiting word about the presence (or absence) of molecular hydrogen, which is formed when water comes into contact with rocks in hydrothermal vents.  Many think that Enceledus is habitable and should be tested for signs of life because biosignatures could potentially exist in the relatively easy-to-access geysers.

While Yuri Beletsky is a staff astronomer at the Las Campanas Observatory in Chile, he is also a noted astrophotographer who specializes in capturing the beauty of nighttime scenes — usually connecting the celestial with the terrestrial.

In this 2016 photo, the moon is surrounded by a halo caused by the presence of millions of ice crystals in the upper atmosphere.  Great conditions for an astrophotographer, but pretty much useless for an astronomer.

The star within the halo is Regulus, brightest object in the constellation Leo the Lion. On the left outside the halo is Procyon from Canis Minor and on the right is the planet Jupiter.

As is so often the case in this line of endeavor, it’s quite a sight to see.

The Ever More Puzzling, And Intriguing, “Tabby’s Star.”

Star debris illustration
Did Tabby’s star going through periodic and deep dimmings because of dust and debris clouds that pass edbetween it and the mirror of the Kepler Space Telescope?  That was an earlier explanation for the highly unusual behavior of the star, but new research makes that answer less likely. Artist drawing by NASA/JPL-Caltech/T. Pyle

Substantial, sun-like stars are not supposed to dim.  They start with gravity and pressure induced nuclear reactions, and then they burn brighter and brighter until they either explode (go supernova) or burn all their fuel and become small, enormously dense, and not very bright “white dwarfs.”

Of course, the transit technique of searching for exoplanets looks precisely for dimmings — of stars caused by the passage of an exoplanet.  But those are tiny reductions in the star’s brightness and short-lived.  So if a star is dimming significantly over a much longer period of time, something unusual is going on.

And that is apparently exactly what is happening with the current poster child for mysterious stars — KIC 8462852 or “Tabby’s star,” named after the Yale University postdoc who, with the help of citizen scientists, discovered it,  Tabetha Boyajian.

First written up last fall, the big news was data from the Kepler Space Telescope showed that the star had experienced two major and dissimilar dips in brightness — a highly unusual and perplexing phenomenon.  The dips appeared much too large to represent the passage of an exoplanet, so explanations tended towards the baroque — a swarm of comets, a vast dust cloud, even an alien megastructure (proposed as a last possible explanation.)  The observation was first identified by citizen planet hunters working with Boyajian, making it an even more compelling finding.

Now the mystery has grown stranger still.  A paper made public last week based on a different kind of Kepler imaging (full-frame imaging) found not two but one enormous dip in the light curve, as well as a surprising and significant dimming the of star over the four year observing period of the space telescope.  The paper has been submitted for publication in American Astronomical Society journals.

Benjamin Montet of Caltech and Joshua Simon of the Observatories of the Carnegie Institution of Washington, analyzed the full-field images taken by Kepler every three months (rather than the hourly images studied by Boyajian et al,) and concluded that something strange was indeed going on.

Their conclusion: “No known or proposed stellar phenomena can fully explain all aspects of the observed light curve.”

Photometry of KIC 8462852 as measured from the FFI data. The four colors and shapes (green squares, black circles, red diamonds, and blue triangles) represent measurements from the four separate channels the starlight reaches as the telescope rolls. The four subpanels show ux from each particular detector individually. The main gure combines all observations together; we apply three linear osets to the data from dierent channels to minimize the scatter to a linear t to the rst 1100 days of data. In all four channels, the photometry is consistent with a linear decrease in ux for the rst three years of the mission, followed by a rapid decrease in ux of  2:5% over the next six months. The light gray curve represents one possible Kepler long cadence light curve consistent with the FFI photometry created by tting a spline to the FFI photometry as described in Section 4. The large dips observed by Boyajian et al. (2016) are visible but narrow relative to the cadence of FFI observations. The long cadence data behind this gure are available online.
Photometry of KIC 8462852 as measured from the full-frame imaging (FFI) data. The four colors and shapes (green squares, black circles, red diamonds, and blue triangles) represent measurements from the four separate channels the starlight reaches as the telescope rolls.  In all four channels, the photometry is consistent with a decrease in starlight for the first three years of the mission, followed by a rapid decrease in flux of  2:5% over the next six months. The large dips observed by Boyajian et al. (2016) are visible
but less broad relative to the FFI observations. (B. Montet and J. Simon)

Expanding a bit, Montet told Gizmodo:  “We spent a long time trying to convince ourselves this wasn’t real. We just weren’t able to.”

A paper describing the results from these full-frame observations went up recently on the prior to printing site arXiv.    The site allows members of the astronomy world to offer critiques, and so the results as now released may not be final.

But the story line does seem pretty clear — that Tabby’s star had one very large period of light dimming and had a secular decline in the light it was sending out over the four years of the Kepler mission.

Boyajian, a newly-appointed Louisiana State University researcher and professor, said that she considers the original findings to be entirely compatible with the newest results, with differences based on how the light was being captured (the once-monthly full-frame Kepler images versus the continuous imaging done of more than 100,000 stars.)

What has also become increasingly clear is that the dimming is not the result of an instrument glitch, and that the surrounding stars are not exhibiting the same unusual behavior.

“As far as we know, dimming is not something stars do; they get larger and brighter,” she said.  “Especially on these remarkably fast time scales, the dimmings are unprecedented for any kind of star.”

Boyajian had initially favored the theory that the light was being blocked by a large swarm of comets, but she said the new results make that more unlikely.  She said it is similarly unlikely that the dimmings are the result of some internal dynamics of the star.  So is it all the result of some alien megastructure, the “explanation” that initially brought a lot of attention to Tabby’s star.  I think we can assume it is not.

But given the data now available, it has become extremely difficult to find an explanation that checks all the boxes.  And that’s why Boyajian and her colleagues began a kickstarter campaign to raise $100,000 for another year of observing through the telescopes of the private Las Cumbres Observatory Global Telescope Network.

As she explained it, one of the telescopes will image the star at least two hours per night for the next year.  And if a significant dimming is observed, larger ground-based telescopes will be available to look more closely.

It’s a waiting game now, which is exciting itself,” she said. “It’s only a guess, but based on Kepler light curves, we might see something interesting next spring.”

(My earlier story on Tabby and her star can be found here:  Tabby’s Star)

Tabetha Boyajian was the driving force behind bringing the mysterious star xxxx to public attention. It had initially been identified as peculiar by the citizen scientists of xxx.
Tabetha Boyajian was the driving force behind bringing the mysterious star KIC 8462852 to public attention. It had initially been identified as peculiar by the citizen scientists of Planet Hunters, which is part of the Oxford University based “Zooniverse” Citizen Science Alliance.

The Still Mysterious “Tabby’s Star”

Artist rendering of star xxx, and the unexplain ed objects close to it. KNown as "Tabby's" star
Artist rendering of dusty comets approaching star KIC8462852, an interpretation of the mysterious objects that periodically block out substantial amounts of the star’s light. Known informally as “Tabby’s” star, it was discovered by citizen scientists using Kepler Space Telescope data, and they are looking for ways to continue their work. (NASA/JPL-Caltech)

It’s been eight months since citizen “Planet Hunters”  working with Yale postdoc Tabetha Boyajian announced the discovery of a most unusual star, or rather a star where something most unusual was intermittently and erratically happening.

The puzzle began with some light curve data, taken over a four year period, by the Kepler Space Telescope  The citizen planet hunters pored through reams of data sent back by Kepler looking for signals of planetary transits — the ever-so-slight dimmings of the star caused by the crossing or an orbiting exoplanet.

But the light curve for KIC 8462852 showed dimmings that were anything but slight, and anything but regular.  The Planet Hunters flagged the star for Boyajian’s groups attention, and the mystery star was born.

Theories on what was causing the very large dips ranged from a host of enormous comets, to a violently exploding planet, to an asteroid belt or the presence of close by stars, from an artifact of Kepler’s camera to, finally, an alien megastructure.  (The last was offered by Penn State astronomer Jason Wright as a kind of “Hail Mary” explanation if and when the others are found wanting.  But that’s what got the press.)

Despite years of concerted observing, theorizing and analyzing, Boyajian, Wright the citizen planet hunters and others intrigued by the mystery say they are no closer to an explanation for whatever is passing in front of the star (now informally called “Tabby’s star.”)  NASA has ruled out a technical glitch in the Kepler data, and a range of astronomers have found fault with all the explanations put forward.

But while the quite tantalizing mystery remains, efforts to learn more about the star may have to wind down soon.  The primary Kepler mission is over, so it will provide no more data for this star.  Other space telescopes will not be looking, nor will the major ground-based observatories.  And  the first SETI searches for signals coming from the star has found nothing unusual.

So with options dwindling to learn more, Boyajian, her citizen astronomers and others have begun a grassroots effort to raise $100,000 to buy time at a network of smaller ground-based telescopes around the world.

“All the models so far have major problem. So to go forward, we need new data ,” Boyajian said this week.  “There’s a huge amount of interest in this star, and we’re trying to use that interest to help solve a real mystery.”

 The unusual light curves for "Tabby's Star," which feature some extremely large dips and other smaller ones. The X-axis label “Kepler day” means days following the Kepler launch. (NASA/Kepler Space Telescope) The unusual light curves for "Tabby's Star," which feature some extremely large dips and other smaller ones. The X-axis label “Kepler day” means days following the Kepler launch. (NASA/Kepler Space Telescope)
The unusual light curves for “Tabby’s Star,” which feature some extremely large dips and other smaller ones. The X-axis label “Kepler day” means days following the Kepler launch. (NASA/Kepler Space Telescope)

KIC 8462852 is an otherwise ordinary F-type star, slightly larger and hotter than our sun . It burns some 1500  light-years away.  Of all the 150,000 stars monitored during the Kepler mission, it is the only one to show these kinds of highly unusual light curves and, presumably, to have such massive astrophysical objects (or fields or other phenomena) nearby.

During a TED talk, Boyajian described the recent history of observing the star.

The Planet Hunters, she said,  first detected something unusual in the star’s light curve in 2009 –a dip of 1 percent dip that lasted a week. This is roughly comparable to a sign produced by a Jupiter-sized planet transiting the star. Orbiting planets produce symmetric dips and the one they found was definitely asymmetric, like something that could be the result of the passing of an irregularly-shaped object like a comet.

The light from the star remained steady for two years, then it suddenly took a 15 percent plunge that lasted for a week.

Another two years passed without incident but in 2013 the star began flickering with a complex series of uneven, unnatural looking dips that lasted 100 days. During the deepest of these dips, the intensity of the light coming from the star dropped 20 percent. According to Boyajian it would take an object 1,000 times the area of the Earth transiting the distant star to produce such a dramatic effect.

What’s causing these unusual and strong signals.  The jury remains very much out.

The Kepler field of study, observed by the space telescope nonstop for almost five years. (NASA)

But the process of applying for grants and space telescope time is both very slow and highly competitive. So the group has decided on a different, self-financing path.  This is how they described their current and future plans on their “” website:

We have initiated observations on the Las Cumbres Observatory Global Telescope Network (LCOGT). LCOGT is a privately run global telescope network specifically designed for time domain astronomy, meaning that their network of telescopes is positioned strategically around the globe to ensure continuous monitoring of an object.

Our observation plan is as follows. From the 4 years of Kepler data, we know that the dips in the light curve are not periodic, so we need continuous monitoring throughout the year since we cannot predict when it will dip again. We also know that how much the brightness drops is also variable from dip-to-dip. The LCOGT data will not have the precision Kepler had, but will have plenty of sensitivity to detect the observed dips in this star.

What’s more, since we are observing this star from the ground we are also able to tailor our observation plan to reveal detailed information on whatever object(s) are passing in front of the star to make the dips! One way this will be done is by observing the star at different wavelengths, or colors, of light. These new observations will monitor the star’s brightness at an assortment of colors!

In addition to this, the data from the LCOGT are space processed in real time, so when data are seen to pass below a brightness threshold, it will trigger more observations in the LCOGT network. Our science team will then alert for observations to be taken at larger facilities to get a better look.

The observatory has gifted this program 200 hours to begin the project on their new 0.4-meter telescope network, which will take us to the end of the summer.

Tabetha Boyajian, a postdoc at Yale and soon to be on the faculty of Louisiana State University.
Tabetha Boyajian, a postdoc at Yale and soon to be on the faculty of Louisiana State University. She has been working to unravel the mysteries of KIC 8462852 since

It’s not at all easy to apply for and win the stiff competition for observing time on a major public telescope, and that reality led to the outreach effort aimed those interested in collecting more Tabby’s Star data. The Planet Hunters citizen scientist group was brought together by Yale professor Debra Fischer, herself a professional planet hunter. The group is part of the Oxford University based “Zooniverse” Citizen Science Alliance.

As I will discuss in a later column, I have my doubts about some of the big-dollar, high-profile individual and foundation efforts to jump-start space travel and space science. They can be wonderful, but they sometimes feel like efforts to get the proverbial camel’s nose into the tent, and NASA and its budget are ultimately the tent.  (I’m not thinking here of commercial space efforts like resupplying the International Space Station, although they too depend on NASA to an important financial and technical degree.)

But grassroots private efforts like this one to learn more about Tabby’s star are, to me at least, quite  different.   This is hardly the first time a private group of enthusiasts has asked the interested public to help with their research and (hopefully) it will not be the last.  At the proper scale and with proper goals, they seem generally like a most valuable part of future space science.

And if this particular effort does end up solving the Tabby’s star puzzle in the months and years ahead — or at least giving some strong possible explanations — it will strenghten the case for public citizen science of all kinds.


Honouring a commitment (life)

Life Insurance 2

Thirty years ago, Mrs. B. purchased life insurance. The premium would change over the years and the cash surrender value would be flexible but, as she understood it, she was guaranteed a paid-up $200,000 policy at age 65. This original policy was subsequently transferred to several insurers over the years.

When she turned 65, Mrs. B. received a letter informing her that her policy was now paid up; no more premiums were necessary to maintain the value of $200,000 and to keep her policy in force. Mrs. B. stopped making payments but, several years later, received a letter advising that her policy was now valued at $158,000.

Although no further premiums were required to keep the policy in force, the insurer stated that the sum insured continued to be reviewed for adjustment. Mrs. B. disagreed and contacted OLHI for a free, independent and impartial review of her file. She provided us with the final position letter and copies of all her correspondence with the various insurers that had owned the policy over the years. We also received the current insurer’s file.

OLHI’s first impression was that there would likely be no grounds to negotiate as the decrease in the sum insured was likely contractual.

However, OLHI’s Dispute Resolution Officer (DRO) discovered that Mrs. B. had a letter from the original insurer, guaranteeing in writing the sum insured of $200,000, with no adjustments to that sum. For this reason, the complaint was escalated to an OmbudService Officer (OSO) for further investigation.

Speaking with the insurer, the OSO concurred that the policy clearly outlines the recalculations of the premiums and the fact that the sum could change after age 65. However, he also noted that the guarantee letter could not be overlooked. The insurer, after additional review, agreed to honour the commitment that the previous insurer had made, confirming that the sum insured would not be recalculated in future.

Disclaimer: Names, places and facts have been modified in order to protect the privacy of the parties involved. This case study is for illustration purposes only. Each complaint OLHI reviews contains different facts and contract wording may vary. As a result, the application of the principles expressed here may lead to different results in different cases.


Accelerated Education

What does Accelerated Education mean?

AEPs are flexible, age-appropriate programmes, run in an accelerated timeframe, which aim to provide access to education for disadvantaged, over-age, out-of-school children and youth – particularly those who missed out on, or had their education interrupted due to poverty, marginalisation, conflict and crisis.

What is the Accelerated Education Working Group?

The Accelerated Education Working Group (AEWG) is made up of education partners working in the field of accelerated education. The AEWG is currently led by UNHCR with representation from UNICEF, UNESCO, USAID, NRC, Plan, IRC, Save the Children, Education Conflict and Crisis Network, and War Child Holland.

The group’s goal is to strengthen the quality of accelerated education programming through a more harmonized, standardized approach.

Why do we have a working group?

Globally, accelerated education programmes are employed with more and more frequency to address the large number of out of school children and youth. However, while there is widespread agreement on the need for such programming among agencies and governments, there is insufficient validated documentation that provides guidance, standards and indicators for efficient programme planning, implementation and monitoring.

In practice, accelerated education takes different forms in different countries, and even within countries. Moreover, there is little significant documentation on its impact, including how much we are contributing to learning achievement and how successful we are at facilitating pathways between accelerated programming and formal and non-formal education.

To address some of these challenges, starting with the lack of guidance and standards, in 2014 UNHCR invited a small number of education partners working in the area to form a working group.

What does the group do?

The AEWG meets biannually to share experiences and expertise in accelerated education and fosters dialogue around a more harmonized, standardized approach. To this end, the group has begun to develop guidance materials based on international standards and sound practice.

For more information please contact Martha Hewison at


My Nights Are More Beautiful Than Your Days

Durata: 110min 14sec Visualizzazioni: 1 216 172 Aggiunto: 11 months ago Utente:
Descrizione: Lucas has invented a new computer language but at the same time he has been informed about his strange terminal illness during which he has been gradually losing his memory. Shortly after that he meets Blanche who acts as a medium in a bizarre traveling show. Dying Lucas follows her to the sea resort where they spend together several days and nights


Complimentary shipping and five day returns. Always.

Meet Christin

“Each rug has a story. Immersing yourself in the where, the who, and the why … I can’t imagine anything more beautiful.” – Christin

About Christin Terrell

“Each rug has a story” is Christin Terrell’s personal motto. She began her career in Oriental rugs, having been deeply influenced by childhood experiences with rugs. Christin, even at a young age was captivated, training herself as a child to spot the differences in dyes and weave constructions. The details, craftsmanship and tradition affected her deeply.

She began traveling directly to the source in an endless quest for these magic carpets. Having taught herself Turkish, she and her husband, Trenton began making regular sourcing trips abroad.

“It was like figuring out a puzzle. I already knew the subtleties of the rugs and their details and processes, but traveling to the source was like a codex of understanding the why, the how and the everything of the rug. Seeing the people who dye by hand, the shepherds who care for the sheep… It gives a vibrant understanding of not just the process, but the people, the history, the tradition.”

While many people look at a rug and see only the vibrant colors, intricate patterns and apparent age and history, Christin sees the beauty and durability of its origins and every pair of hands and bead of sweat that went into making the rug; “Immersing yourself in the where, the who, the why… I can’t imagine anything more beautiful.”

One of a kind new arrivals are announced quarterly.
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Colin was totally genuine, honest and helpful throughout the whole transaction process.  He always responded quickly to queries and explained things to be easily understandable.  He has a lovely friendly manner and was an absolute pleasure to deal with.  I would recommend him to anyone.  Also Lisa Dunham has been very helful and efficient.  Excellent Staff.


Quarterly Journal of Austrian Economics

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Home | Mises Library | Economic Calculation in the Environmentalist Commonwealth

Economic Calculation in the Environmentalist Commonwealth

  • The Quarterly Journal of Austrian Economics

Tags Calculation and Knowledge

07/30/2014Art Carden

Volume 16, No. 1 (Spring 2013)

ABSTRACT: Non-monetary calculation of the environmental effects of action runs into the same problems of in natura calculation and commonly owned means of production. The information needed for rational economizing does not exist when we forsake the price mechanism. A legal regime based on strict private property rights solves environmental problems and minimizes conflict in the coordination of plans. Relaxed restrictions on property rights can move many currently political decisions into the realm of market exchange and improve economic coordination. Reducing restrictions on housing markets provides one example.

KEYWORDS: environment, Austrian economics, prices, profits and losses

Art Carden1

Do government services and even private proposals like carbon accounting, “triple bottom line” accounting, and measurement of “food miles” provide viable alternatives to monetary calculation based on profit and loss? Are they alternative ways to evaluate production and allocation, or might they merely serve the same function as advertising and image-improving or trust-enhancing charity? The necessity of monetary calculation for rational economic decision-making suggests that alternative measures of environmental impact do not provide reliable guides to policy. Even proposals that take at least some advantage of the price mechanism, like Pigovian taxes or formal markets for permits to emit substances like carbon dioxide, encounter calculation and knowledge problems. Coordination improves, and unintended negative consequences are minimized when people are able to trade voluntarily.

As Cordato (2004, p. 3) writes, environmental problems “are not about the environment per se, but about the resolution of human conflict” and the coordination of individual plans. In this light, Cordato (2004, p. 4) proposes an approach to efficiency that focuses on the processes by which goals are achieved, errors are eliminated, conflicts are reduced, and transgressions are rectified. He notes that

[e]fficiency is a “praxeological,” i.e., individual goal seeking problem, not a value maximization problem. From a policy perspective, then, social efficiency is assessed in terms of the extent to which legal institutions facilitate consistency between the ends that actors are pursuing and the means that they are choosing to accomplish those ends. (Cordato, 2004, p. 4)

Environmental problems are coordination problems. Specifically, they are problems of reconciling mutually exclusive plans by identifying and correcting individual encroachments on others’ rights: “[g]enerally formulated, a pollution or environmental problem arises when individual or group A and individual or group B are simultaneously attempting or planning to use resource X for conflicting purposes.” (Cordato, 2004, p. 7) Cordato’s approach has implications for how we understand non-market environmental planning.

Regulation substitutes power for market, to rephrase the title of Rothbard (1970 [1977]). In a contribution that ignited the socialist calculation debate, Mises (1920 [1990]) demonstrated that rational economic calculation is impossible when the means of production are commonly owned.2 Hayek (1945) argued that the economic problem is not the complex optimization problem implied by the thesis that a socialist economy can calculate; rather, it is a problem of assembling, evaluating, and updating dispersed knowledge. Therefore, even if a socialist economy could engage in rational economic calculation in some abstract sense, the institutions of private property are prerequisites for the creation of the necessary information.3

Prices economize on the knowledge necessary for rational calculation (Hayek, 1945, p. 525), and Hayek (2002) argued that competition is “a discovery procedure” whereby information that cannot be known by a single mind is used and revealed. The market is “a procedure for discovering facts which, if the procedure did not exist, would remain unknown or at least not used” (Hayek, 2002, p. 9). Private property and unfettered exchange are necessary for rational economic calculation. Hülsmann (1997), Mahoney (2002), and Cordato (2004) augment these original contributions and lay the groundwork for a praxeological approach to environmental concerns.4

Among other things, monetary calculation reduces the cognitive overload associated with a complex reality and allows us to order and interpret the world around us. Specifically, monetary calculation

Consumers might value information about the carbon emissions needed to produce a particular good, the number of miles traveled by a head of lettuce, or a firm’s record on minority hiring, but the degree to which they value these attributes will be reflected in prices, profits, and losses.

This is apparent in at least some environmental initiatives. In natura calculation is plainly impossible, but proposals for markets in tradable emissions permits do take advantage of the price mechanism to a degree. As McGee and Block (1994) argue, however, they run into the same problems associated with proposals to implement “market socialism.” Tradable permits and Pigovian taxes are market-like, but they still rest on a planner’s conceit that the optimal amount of a particular activity can be known independent of what is revealed by trade (or more generally, by consent). Cordato (2004, p. 11) criticizes the “polluter pays” principle:

Most specifically, a central authority must know in advance what the efficient outcome is. In the case of the tax, a central authority must know in advance the exact amount of the externality costs being imposed by the polluter, and the correct price and output, not only for the good in question but, since efficiency only makes sense in a general equilibrium context, for all other affected goods and services. In the case of tradable permits, the knowledge requirements are essentially the same.

Nye (2008) goes further within the confines of conventional neoclassical economics: the effects of other taxes in general equilibrium, possible monopoly power, and the possibility of Coasean side bargains mean that even the ability to observe and measure the precise size of the externality is not a reliable guide to policy. Borrowing from Coase, he writes:

Even in a world of positive transaction costs, some Coasian transfers may take place that partly mitigate the harm of an externality. Unless the Pigovian tax collector can fully account for all those transfers, any estimate of an appropriate tax based solely on the size of the externality will clearly overstate the optimally efficient tax level. (Nye 2008, p. 32)

As Nye notes, even if we can calculate an externality of gasoline consumption of $1 per gallon, for example, regulations like Corporate Average Fuel Economy standards (which economists generally dislike), possible market power for organizations like OPEC, the impact of taxes in other sectors of the economy, and a host of other considerations will move the number of gallons consumed closer to the social optimum even though we still observe $1 per gallon in external effects. Nye cites Bovenberg and Goulder (1996), who argue that the general equilibrium optimal Pigovian tax is likely to be lower than the partial equilibrium optimum (and possibly negative) when there is general taxation. Block (2003) discusses possible privatization of the roads; this could mitigate some of the external costs of fossil fuel consumption if firms with some market power control the roads (cf. Buchanan 1969).

Establishing clear private property rights over previously unowned resources makes them tradable. This allows people to calculate, or to evaluate the relative costs and benefits of different courses of action. As Cordato (2004) reminds us, environmental conflicts are always conflicts of ownership: some people wish to use a resource to achieve one set of goals. Others wish to use the same resource to satisfy a different set of goals. Property owners’ use of property and the negotiations between people bidding for property establish prices. The establishment of cardinal, money prices creates a common standard of comparison (Mises, 1920 [1990]).

Profits and losses allow entrepreneurs to appraise the results of their actions and determine whether what they have produced allows people to satisfy more urgently felt wants, or whether it causes people to satisfy less urgently felt wants. In the first case, the entrepreneur earns a profit. In the second case, the entrepreneur earns a loss. Mahoney (2002, p. 48) makes a crucial point with respect to private ownership that is directly relevant to environmental questions: while we can know physical quantities, we cannot appraise economic scarcity—or more generally, praxeological scarcity—without private ownership and the prices produced by market exchange.

Property is necessary for even the clear identification of environmental trouble and also for the solution of such troubles. Hülsmann (1997) criticizes the thesis that economics is concerned primarily with coordination and the use of knowledge and argues instead that “(i)t is property, rather than knowledge, that coordinates the separate actions of different people” (Hülsmann, 1997, pp. 28–29). Property is a prerequisite for the application of knowledge to the creation of value. Technological knowledge, even knowledge of the full range of technological combinations that might produce all possible arrays of physical output, is neither necessary nor sufficient for rational economic calculation. As Hülsmann (1997, p. 44) notes,

[W]ithout reference to our property we could not possibly select knowledge in terms of importance. Moreover, once we own property we then know which kind of knowledge could be useful. It is this property that directs our learning toward useful channels.

The property regime determines the kinds of knowledge that are sought and deployed. People generally seek and deploy knowledge that helps them better achieve their goals. With secure private property rights, such knowledge will be value-productive; i.e., the property owner will generally deploy knowledge that helps him achieve his goals without interfering with another’s ability to do the same. Errors will be weeded out through losses, and uses of property that interfere with others’ property rights will be corrected by appropriate legal institutions (Hülsmann, 1997, pp. 44–45). Hülsmann describes how the introduction of coercion and the abrogation of private property rights alters the process:

The case is different in a system featuring a coercive agency. Here, by definition, a knowledge different from value-productive knowledge is, at least sometimes, more important. (The extent of “sometimes” depends on the range of activities and on the permanence of the coercive agency). There is, for example, the knowledge of how to reap the fruits of other persons’ labor without provoking their resistance. There is also the knowledge of how to acquire control and ownership of the coercive agency. And there is the knowledge of how to persuade one’s neighbors about the utility of this system, too. One can add an infinite number of items to this list. The result, in general terms, remains the same: a violent agency necessarily affects the knowledge structure of the society upon which it is imposed. (1997, p. 45)

What are the implications of violence’s effect on the “knowledge structure” for environmental policy? Environmentalists identify an important problem: one’s actions interfere with the property rights of another. Some gains from trade are unrealized because some of the valuable attributes of some goods and services are unowned and therefore not priced. Proposals for planning based on carbon footprint measurement replace this problem with one that is even worse: specifically, forsaking the price mechanism introduces arbitrariness into production and consumption decisions. There are ways to mitigate these problems by strengthening private property rights and thereby making more potential conflicts subject to resolution through trade or tort law (cf. Rothbard, 1982). Disharmony between individuals’ plans arises from conflicts over the use of resources; this disharmony can be eliminated or substantially reduced by, for example, eliminating building restrictions and privatizing what has been socialized.

Consider the examples of building restrictions and socialized garbage collection. Glaeser and Kahn (2008) argue for relaxing housing restrictions in California. Per capita emissions are lowest on the west coast and highest in the South, and in cities like Boston and New York per capita emissions are lower in the city whereas in Los Angeles they are lower in the suburbs (Glaeser and Kahn, 2008, p. 1). They estimate that, for example, the annual additional cost of carbon dioxide emissions from a home in metropolitan Houston is approximately $500 more than it would be in metropolitan San Francisco. They attribute this mostly to the better climate in the San Francisco Bay area. Even for all of their careful work, their knowledge is of a meager and unsatisfactory kind: they note that they do not include the carbon emissions associated with work. Land use restrictions precisely invert the practices consistent with wise environmental stewardship. Land in California and New York that would be more valuable for housing is used to grow crops, while land in Texas that would be more valuable for crops is used to build housing.5

Further, Glaeser (2006), Glaeser and Gyourko (2003), Glaeser and Ward (2006), and Glaeser et al. (2005) argue that land use restrictions have artificially inflated housing prices in places like California, Boston, and New York. “Affordable housing” mandates do not work, as Powell and Stringham (2004) show; indeed, Means and Stringham (2009) estimate that affordable housing mandates have higher housing prices and smaller housing stocks in the California cities that have adopted them. Relaxing these restrictions helps us save multiple birds with a single stone: we get cheaper housing that is cheaper to operate, and we eliminate restrictions that interfere with market plan coordination.

Pollution externalities emerge from socialized garbage collection (Block, 1998, p. 1894), which means the prices for garbage collection do not reflect their costs and benefits. In many places, one can throw away a garbage can filled with toxin-laden cell phone batteries for the same price as a garbage can filled with biodegradable vegetable matter. Pricing garbage disposal might lead to more illegal dumping, but the solution in this case would be stronger enforcement of private property rights, not socialized garbage collection. Bringing garbage collection into the cash nexus of market exchange would bring them under the discipline of the process by which costs and benefits are revealed.

Cordato (2004, p. 4) describes the institutional character of the Austrian-praxeological approach to efficiency: “…social efficiency is assessed in terms of the extent to which legal institutions facilitate consistency between the ends that actors are pursuing and the means that they are choosing to accomplish those ends.” The policy problem with regard to efficiency concerns “efficient intra- and inter-personal plan formulation and execution, i.e., the internal consistency between the means that people use and the ends they desire to achieve” (Cordato, 2004, p. 7). Such efficient coordination is impossible without secure private property rights. Brätland (2006, p. 15) is explicit, pointing out that “without private property and monetary exchange, there can be no capital calculation and no rational means of maintaining either capital or income for current or future generations” (emphasis in original).

Calculation problems have further implications for how we understand the concept of “sustainable development.” Sustainable development requires praxeological, calculation-based microfoundations. Taylor (2002, p. 4) notes that what is being “sustained” may be of little value to those yet born; to adopt an example from Steven Landsburg (1996), who are we to say that our children would prefer a forest to the income generated by a parking lot? Further, as Landsburg and others have noted, since future generations will almost certainly be far wealthier than we are, conservation for future generations’ sake is an intergenerational redistribution from the relatively poor of today to our relatively rich descendants.

Non-price calculation instruments do not provide a basis for rational analysis, rational calculation, and rational action because they forsake the market (Brätland, 2006, p. 21). Private property owners have a direct interest in maintaining and increasing the value of their property. Further, the entrepreneurial process ensures that at any point in time, the best answer to Landsburg’s question about how we know whether future generations prefer a forest to a parking lot will be capitalized into the prices of the land and other resources. At every point in time, the price of an asset reflects market participants’ best estimates of the discounted present value of the income that will be generated by that asset. When private property rights are secure, anyone who values green space as such or who believes that people are making a short-sighted mistake by paving green space is free to act on these preferences and beliefs.

Should we treat future generations’ utilities as if they were our own and not discount the future? A simple reductio ad absurdum shows that this is untenable.6 If we truly should not discount the future, then the relevant environmental problem is not that we may someday exhaust the Earth’s resources but that someday the sun will die out, explode, and destroy everything in our solar system. This leads us to conclude that we should increase rather than decrease the rate at which we extract resources as we look for ways to get off of this doomed rock.

Science can measure some aspects of a production process, but even these measurements produce knowledge that is of a very meager and unsatisfactory kind. Following Garrison (2000), we can simplify the discussion by dividing the structure of production into five stages of mining, refining, manufacturing, distributing, and retailing. It is possible to measure the energy inputs and carbon outputs of certain parts of certain processes in the structure of production—the carbon output of a diesel truck moving cans of Pepsi from a warehouse to a grocery store is reasonably easy to measure, for example. However, what we can measure easily represents only a fraction of what really goes into the production process.

Consider the production process that gets a can of Pepsi into our refrigerators.7 One could probably measure the carbon dioxide produced in the production and operation of the machines in the soda bottling facility. But what about the carbon dioxide emitted by workers commuting to the factory? Or the carbon dioxide emitted to brew their morning coffee? Or the carbon dioxide emitted to produce that coffee, get it to the grocery store, and then to the worker’s home? Any attempt to identify a non-price metric by which people can decide whether value is or is not being created runs into the same problem a central planning board runs into when it attempts to allocate scarce and unowned factors of production. The problem cannot be solved because the relevant information has been destroyed.

Public choice considerations are relevant, as well. Hasnas (2009, pp. 121–122) recounts the well-known case of environmental regulation in which Senator Robert Byrd intervened on behalf of coal mining interests. The regulations were not written to allow certain levels of pollution; rather, they were written to require that smokestacks at coal-burning power plants be fitted with air scrubbers “even though requiring scrubbers had greater costs and left the air dirtier” (Hasnas, 2009, pp. 121–122). Here is Hasnas (2009, p. 122): “Requiring the air to be cleaned after the coal was burned neutralized the economic advantages of the cleaner-burning coal mined in the western United States over the dirty-burning coal mined in West Virginia.” Politics also has a bias toward action, prudent and otherwise. Hasnas (2009, pp. 118–119) offers an analogy from soccer in which he says that a defender who appears to be “doing nothing” is often in fact containing the attacker while the defense gets into formation.

While the market socialism of tradable permits enables better economic calculation than command-and-control regulations, secure private property rights allow for the generation of knowledge that is essential to the solution of environmental problems. Block (1990, p. 91), for example, suggests scaling back interventions that create conflicting plans over the uses of water and air. The same problem of market socialism remains: a “bureaucratic command structure” regulates the permit-trading market (McGee and Block, 1994, p. 56).

What do we do about the well-known problems of externalities and public goods? There are several answers. First, private property rights combined with the common law of torts brings these considerations into the sphere of economic calculation (Rothbard, 1982 [1997]; Hasnas, 1996, 2009). Legal decisions in the early nineteenth century held that it was in the public interest to encourage manufacturing; therefore, pollution forensics and the abilities of people to sue polluters were sharply curtailed (Block, 1990, p. 91; 1998, p. 1890). McGee and Block (1994, pp. 61–62) discuss “reasonable” conduct and “live and let live” principles in English and American law, and indeed custom is likely to emerge in ways that encourage efficiency. Second, as Elinor Ostrom’s research shows, people are remarkably adept and managing common-pool resources without heavy-handed central planning.8

Extending Caplan’s (2007) argument about the inefficiency of policies chosen by democracies, Carden and Hammock (2010) suggest that environmental policies are also likely to be flawed. Respondents to a 2007 Washington Post/ABC News Poll, for example, opposed higher gas taxes but supported stronger efficiency standards for cars, which Carden and Hammock characterize as “stick-it-to-the-man bias.” Since voters’ preferences are systematically biased they are likely not to support environmental policies that have plausible economic rationales but policies that are positively destructive (Carden and Hammock, 2010, pp. 73–74). Those who assume that regulators can fix it often commit what Otteson (2010) called “the great mind fallacy,” which assumes that someone, somewhere is possessed of sufficient moral and intellectual fiber to engineer a Great Society. Without private property, exchange, and money prices as guides, no mind—no matter how great—can begin to articulate the social problem, much less solve it.

In addition to attempts to measure social and environmental issues at a national level, some activists have pushed firms to adopt “corporate social responsibility” practices like the adoption of a “triple bottom line.” The triple bottom line receives a devastating critique from Norman and MacDonald (2004), who devote most of their criticisms to the social component of a triple bottom line but note that the same criticisms also apply to the environmental component. Advocates of a triple bottom line suggest “that a corporation’s ultimate success or health can and should be measured not just by the traditional financial bottom line, but also by its social/ethical and environmental performance” (Norman and MacDonald, 2004, p. 243).

It is important to note that emphases on environmental and social prerogatives can be important elements of brand management (Norman and MacDonald, 2004), but the idea that firms should seek to let a “triple bottom line” guide their actions runs into a number of obvious problems. The most obvious problem is that there is no way to construct a social or an environmental bottom line. One can know, for example, the percentage of office paper that gets recycled, the amount of energy used by company buildings, and the percentage of company employees who drive hybrid cars. Laying aside for a moment the question of whether these represent unambiguously good environmental stewardship, there is no way to transform this information into a coherent index that represents a real environmental bottom line.

As areas of focus for a firm engaged in careful brand management, these individual pieces of information can be combined to provide a broad overview of a company. They cannot, however, be reduced to a common unit independent of monetary calculation that tells a company whether, say, recycling less office paper is wise if it means being able to use less energy in its buildings. Attempts to add up the components of an environmental bottom line are attempts to add apples to oranges. The problem of in natura calculation that formed part of the Misesian critique of socialism appears again here.

The same problem arises when we consider tradeoffs between financial, social, and environmental goals. Even if we assume that firms can construct coherent indices of their social and environmental bottom lines, there is no way to tell whether a one-unit reduction in the firm’s social bottom line is an acceptable price to pay for a two-unit improvement in the firm’s environmental bottom line, or whether the firm should sacrifice one million dollars in profits to improve its social and environmental bottom lines by one unit each. It is true that a firm could use market prices for recycled paper and energy to estimate the costs of reducing its recycling efforts in order to conserve energy, but this information goes straight to the financial bottom line. As Norman and MacDonald (2004, p. 243) summarize their conclusions, “what is sound about the idea of a Triple Bottom Line is not novel, and… what is novel about the idea is not sound.” Reporting data on corporate environmental and social citizenship might be a good way to attract customers, employees, and some shareholders, but the only coherent measure of a firm’s performance is its financial bottom line. Quite apart from whether the social and environmental indicators have the right arguments, there is no way to articulate the tradeoffs between dollars, social units, and environmental units.

Environmental issues have been pushed to the front of policy debates, and people have proposed a number of interventions, programs, and ideas that are supposed to provide alternatives to monetary calculation. However, monetary calculation solves these problems when property rights are clearly defined. The absence of private property rights means that we cannot have the information we would need to make production and allocation decisions that coordinate producers’ plans with consumers’ wants.

The calculation problem is fundamental to the environmentalist commonwealth just as it is fundamental to the socialist commonwealth. Mises (1990 [1920], p. 13) argues that “(e)very step that takes us away from private ownership of the means of production and from the use of money also takes us away from rational economics.” In the environmental context we can rephrase this as follows: every step that takes us away from private ownership of the means of production and monetary calculation also takes us away from rational and responsible environmental stewardship.

Block, Walter. 1990. “Resource Misallocation, Externalities and Environmentalism: A U.S.-Canadian Analysis.” Proceedings of the 24th Northwest Regional Economic Conference: 91–94.

——. 1998. “Environmentalism and Economic Freedom: The Case for Private Property Rights.” Journal of Business Ethics 17, no. 16: 1887–1899.

——. 2003. “Overcoming Difficulties in Privatizing Roads.” Etica & Politica/Ethics & Politics 2. Available at: http://www.units.it/etica/2003_2/BLOCK.htm.

Bovenberg, A. Lans, and Lawrence H. Goulder. 1996. “Optimal Environmental Taxation in the Presence of Other Taxes: General-Equilibrium Analyses.” American Economic Review 86, no. 4: 985–1000.

Brätland, John. 2006. “Toward a Calculational Theory and Policy of Intergenerational Sustainability.” Quarterly Journal of Austrian Economics 9, no. 2: 13–45.

Buchanan, James M. 1969. “External Diseconomies, Corrective Taxes, and Market Structure.” American Economic Review 59, no. 1: 174–177.

Carden, Art, and Mike Hammock. 2010. “The Truthiness Hurts.” Economic Affairs 30(2):71-76.

Cordato, Roy. 2004. “Toward an Austrian Theory of Environmental Economics.” Quarterly Journal of Austrian Economics 7, no. 1: 3–16.

Garrison, Roger. 2000. Time and Money: The Macroeconomics of Capital Structure. London: Routledge.

Glaeser, Edward L. 2006. “The Economic Impact of Restricting Housing Supply.” Rappaport Institute for Greater Boston Policy Brief PB–2006–3.

Glaeser, Edward L., and Joseph Gyourko. 2003. “The Impact of Building Restrictions on Housing Affordability.” Federal Reserve Bank of New York Economic Policy Review 9, no. 2: 21–39.

Glaeser, Edward L., and Matthew Kahn. 2008. “The Greenness of Cities.” Rappaport Institute for Greater Boston and Taubman Center for State and Local Government Policy Brief, March.

Glaeser, Edward L. and Bryce Adam Ward. 2006. “The Causes and Consequences of Land Use Regulation: Evidence from Greater Boston.” Harvard Institute of Economic Research Discussion Paper No. 2124.

Glaeser, Edward L., Joseph Gyourko, and Raven Saks. 2005. “Why is Manhattan So Expensive? Regulation and the Rise in Housing Prices.” Journal of Law and Economics 48, no. 2: 331–370.

Hamowy, Ronald. 1996. “Some Comments on the Rhetoric of the Environmental Movement.” Journal of Libertarian Studies 12, no. 1: 161–177.

Hasnas, John. 1996. “What’s Wrong With a Little Tort Reform?” Idaho Law Review 32. Available at: http://faculty.msb.edu/hasnasj/GTWebSite/TortReformFinalDraft.pdf.

——. 2009. “Two Theories of Environmental Regulation.” Social Philosophy and Policy 26, no. 2: 95–129.

Hayek, Friedrich A. 1945. “The Use of Knowledge in Society.” American Economic Review 35, no. 4: 519–530.

——. 2002. “Competition as a Discovery Procedure.” Marcellus S. Snow, trans. Quarterly Journal of Austrian Economics 5, no. 3: 9–23.

Hoppe, Hans-Hermann. 1996. “Socialism: A Property or Knowledge Problem?” Review of Austrian Economics 9, no. 1: 143–149.

Huebert, Jacob H., and Walter Block. 2007. “Space Environmentalism, Property Rights, and the Law.” University of Memphis Law Review 37, no. 2: 281–309.

Hülsmann, Jörg Guido. 1997. “Knowledge, Judgment, and the Use of Property.” Review of Austrian Economics 10, no. 1: 23–48.

Landsburg, Steven. 1996. The Armchair Economist. New York: Free Press.

Lavoie, Don. 1985. Rivalry and Central Planning: The Socialist Calculation Debate Reconsidered. Cambridge: Cambridge University Press.

Mahoney, Dan. 2002. “Ownership, Scarcity, and Economic Decision Making.” Quarterly Journal of Austrian Economics 5, no. 1: 39–56.

McGee, Robert W. and Walter E. Block. 1994. “Pollution Trading Permits as a Form of Market Socialism and the Search for a Real Market Solution to Environmental Pollution.”Fordham Environmental Law Journal 6, no. 1: 51–77.

Means, Tom, and Edward Stringham. 2009. “The Effect of Below-Market Housing Mandates on Housing Markets in California.” Working Paper, San Jose State University and Trinity College.

Mises, Ludwig von. 1920. Economic Calculation in the Socialist Commonwealth, S. Adler, trans. Available at: www.mises.org. 1990.

Nelson, Robert H. 2010. The New Holy Wars: Economic Religion vs. Environmental Religion. University Park, Penn.: Penn State University Press.

Norman, Wayne, and Chris MacDonald. 2004. “Getting to the Bottom of ‘Triple Bottom Line.’” Business Ethics Quarterly 14, no. 2: 243–262.

Nye, John V.C. 2008. “The Pigou Problem.” Regulation 31, no. 2: 32–37.

Ostrom, Elinor. 2010. Beyond Markets and States: Polycentric Governance of Complex Economic Systems. American Economic Review 100, no. 3: 641–672.

Otteson, James. 2010. “Adam Smith and the Great Mind Fallacy.” Social Philosophy and Policy 27, no. 1: 276–304.

Munger, Michael. 2007. “Think Globally, Act Irrationally: Recycling.” Library of Economics and Liberty, July 2. Available at: http://www.econlib.org/library/Columns/y2007/Mungerrecycling.html#.

Powell, Benjamin, and Edward Stringham. 2004. “Housing Supply and Affordability: Do Affordable Housing Mandates Work?” Reason Public Policy Institute Policy Study 318.

Pritchett, Lant. 2006. Let Their People Come: Breaking the Gridlock on Global Labor Mobility. Washington, D.C.: Center for Global Development. Available at: http://www.cgdev.org/content/publications/detail/10174.

Roberts, Russell. 2001. “I, Pepsi.” The Freeman, June. Available at: http://www.thefreemanonline.org/columns/i-pepsi/.

Rothbard, Murray N. 1970. Power and Market: Government and the Economy. Kansas City: Sheed, Andrews, and McMeel, 1977.

——. 1982. “Law, Property Rights, and Air Pollution.” Cato Journal 2, no. 1: 55–99. Reprinted in Murray N. Rothbard, 1997. The Logic of Action Two: Applications and Criticisms from the Austrian School. Cheltenham, U.K.: Edward Elgar Publishing, pp. 121–170.

Salerno, Joseph T. 1990. “Postscript: Why a Socialist Economy is ‘Impossible.’” Available at www.mises.org.

Sowell, Thomas. 2008. Economic Facts and Fallacies. New York: Basic Books.

——. 2010. The Housing Boom and Bust, 2nd ed. New York: Basic Books.

Taylor, Jerry. 2002. “Sustainable Development: A Solution in Search of a Problem.” Cato Institute Policy Analysis No. 449.

  • 1. Art Carden (wcarden@samford.edu) is Assistant Professor of Economics in the Brock School of Business at Samford University. Students and colleagues (particularly Mike Hammock) at Rhodes College provided valuable discussions, as did session participants at the 2010 Association of Private Enterprise Education meetings. I thank an anonymous referee for valuable comments.
  • 2. Some of the implications of Mises’s thesis are explored by Salerno (1990).
  • 3. See Lavoie (1985) for a survey of the socialist calculation debate. See also Hoppe (1996, especially pp. 143–144) for a critique of Hayek.
  • 4. Hülsmann (1997), like Hoppe (1996), is critical of Hayek’s characterization of the economic problem as a problem of knowledge and coordination.
  • 5. See Sowell (2008, pp. 23–36; 2010) for a more detailed exploration of the economics of housing in California.
  • 6. I first heard this example from Walter Block.
  • 7. This is adapted from an example given by Roberts (2001).
  • 8. See Ostrom (2010) for a comprehensive summary.

Cite This Article

Carden, Art. "Economic Calculation in the Environmentalist Commonwealth." The Quarterly Journal of Austrian Economics 16, No. 1 (Spring 2013): 27–44.

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Can You Be Farsighted And Nearsighted At The Same Time?

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An eye problem can happen to you at any stage in life. Hence, OPT Clinic provides eye exams in Edmonton so that you can detect your eye problems at an early stage and get it treated. The most common eye problem people experience is vision change. Some people cannot see the nearby objects clearly. While there are others, who cannot see the objects placed at a certain distance clearly. But is it possible that a person is unable to clearly see both the objects kept near to him and objects placed at a distance? Before we answer this question, let’s see what exactly is nearsightedness and farsightedness problem.

What is Nearsightedness?

Myopia or nearsightedness is the most common refractive error in which people are unable to clearly see the objects placed at a distance. When a person suffers from myopia, the eyeball becomes too long for the focusing power of the cornea and the lens. This makes the light focus on the front of the retina instead of reaching the behind surface. When the cornea or lens is too curved, it leads to myopia.

What is Farsightedness?

Hypermetropia, also known as hyperopia or farsightedness, is a refractive error in which the person is unable to see the nearby objects clearly. In this, the light which should focus on retina reaches behind on the surface. The size of the eyeball is generally shorter than normal. A misshapen cornea or lens can also cause hypermetropia.

What is Anisometropia?

Anisometropia is a refractive error where a person might have different vision power in both the eyes. This difference interferes with the normal binocular vision making it difficult for you to see. You might see an object bigger in one eye and smaller in the other. This makes your vision completely blur. Lazy eye or amblyopia is the most common outcome of anisometropia. Sometimes there is a chance that you may suffer from anisometropia from your birth itself. But as you age, the size of the lens also changes and it is a possibility that this refractive error is treated on its own.

Types of Anisometropia

  • Simple Anisometropia: Only one eye has a refractive error while the other is completely normal. The error can be myopia or hyperopia.
  • Compound Anisometropia: With this, both eyes are either myopic or hyperopic but have a difference in the power of vision.
  • Mixed Anisometropia: For Mixed Anisometropia, both eyes have a refractive error, but one eye is myopic while other is hyperopic.

So, can you be farsighted and nearsighted at the same time? Of course, yes! If you are suffering from mixed anisometropia, you can be farsighted and nearsighted at the same time. To know the exact power of both your eyes, it is important to go through an eye exam. Your optometrist will use eye dilation process to make your eye look more clear and enlarged. The good news is, OPT Clinic is providing eye exams in Edmonton at minimal cost. So, then get your eyes examined and also get the right treatment for all your eye problems with our professional optometrist in Edmonton.