Artist's conception of city lights on an alien planet. Credit: David A. Aguilar (CfA)
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When most people think about the search for alien life, the first thing that usually pops into mind is SETI (Search for Extraterrestrial Intelligence). Primarily a search for extraterrestrial radio signals, another more recent facet of SETI is now looking for laser pulses as a conceivable means of communication across interstellar distances. But now, a third option has been presented: looking for sources of artificial light on the surfaces of exoplanets, like the lights of cities on Earth.
According to Avi Loeb at the Harvard-Smithsonian Center for Astrophysics, “Looking for alien cities would be a long shot, but wouldn’t require extra resources. And if we succeed, it would change our perception of our place in the universe.”
Like the other SETI initiatives, it relies on an assumption that an alien civilization would use technologies that are similar to ours or at least recognizable. That assumption itself has been the subject of contentious debate over the years. If an alien society was thousands or millions of years more advanced than us, would any of its technology even be recognizable to us?
That aside, how easy (or not) would it be to spot the signs of artificial lighting on an alien planet light-years away from us? The suggestion is to look at the changes in light from an exoplanet as it orbits its star. Artificial light would increase in brightness on the dark side of a planet as it orbits the star (as the planet goes through its phases, like our Moon or other planets in our own solar system), becoming more visible than any light that is reflected from the day side.
That type of discovery will require the next generation of telescopes, but today’s telescopes could test the idea, being able to find something similar as far out as the Kuiper Belt in our solar system, where Pluto and thousands of other small icy bodies reside. As noted by Edwin Turner at Princeton University, “It’s very unlikely that there are alien cities on the edge of our solar system, but the principle of science is to find a method to check. Before Galileo, it was conventional wisdom that heavier objects fall faster than light objects, but he tested the belief and found they actually fall at the same rate.”
The paper has been submitted to the journal Astrobiology and is available here.
Three people enjoy the summer sky over the Delaware river, NJ, USA in August 2006. Image Credit: Wikimedia
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It’s a great time to be an amateur astronomer! Nowadays, “backyard” astronomers armed with affordable CCD imagers, high-quality tracking mounts, inexpensive PC’s and the internet at their fingertips are making real contributions to Astronomy science.
How are people in their backyards contributing to real science these days?
Consider that in 1991, the Hubble Space Telescope launched with a main camera of less than 1 megapixel. (HST’s array was 800×800 pixels – just over half a megapixel). Currently, “off-the-shelf” imaging equipment available for a few hundred dollars or less easily provides 1 megapixel or more. Even with a “modest” investment, amateurs can easily reach the ten megapixel mark. Basically, the more pixels you have in your imaging array, the better resolution your image will have and the more detail you’ll capture (sky conditions notwithstanding).
With access to fairly high resolution cameras and equipment, many amateurs have taken breathtaking images of the night sky. Using similar equipment other hobbyists have imaged comets, supernovae, and sunspots. With easy access to super-precise tracking mounts and high-quality optics, it’s no wonder that amateur astronomers are making greater contributions to science these days.
One spectacular example of amateur discoveries was covered by Universe Todayearlier this year. Kathryn Aurora Gray, a ten year old girl from Canada, discovered a supernova with the assistance of her father and another amateur astronomer, David Lane. The discovery of Supernova 2010lt (located in galaxy UGC 3378 in the constellation of Camelopardalis) was Kathryn’s first, her father’s seventh and Lane’s fourth supernova discovery. You can read the announcement regarding Ms. Gray’s discovery courtesy of The Royal Astronomical Society of Canada at: http://www.rasc.ca/artman/uploads/sn2010lt-pressrelease.pdf
Often times when a supernova is detected, scientists must act quickly to gather data before the supernova fades. In the image below, look for the blinking “dot. The image is a before and after image of the area surrounding Supernova 2010lt.
A before and after animation of Supernova 2010lt. Credit: Dave Lane
Before Kathyrn Gray, astronomer David Levy made headlines with his discovery of comet Shoemaker-Levy 9. In 1994, comet Shoemaker-Levy 9 broke apart and collided with Jupiter’s atmosphere. Levy has gone on to discover over twenty comets and dozens of asteroids. Levy has also published several books and regularly contributes articles to various astronomy publications. If you’d like to learn more about David Levy, check out his internet radio show at http://www.letstalkstars.com/, or visit his site at http://www.jarnac.org/
Hubble image of comet P/Shoemaker-Levy 9, taken on May 17, 1994. Image Credit: H.A. Weaver, T. E. Smith (Space Telescope Science Institute), and NASAThe International Space Station and Space Shuttle Atlantis transiting the sun. Image Credit: Thierry Legault
Rounding out news-worthy astronomers, astrophotographer Thierry Legault has produced many breathtaking images that have been featured here on Universe Today on numerous occasions. Over the past year, Thierry has taken many incredible photos of the International Space Station and numerous images of the last few shuttle flights. Thierry’s astrophotography isn’t limited to just the sun, or objects orbiting Earth. You can read more about the objects Thierry captures images of at: http://www.astrophoto.fr/ You can also read more about Thierry and the equipment he uses at: http://legault.perso.sfr.fr/info.html
Performing science as an amateur isn’t limited to those with telescopes. There are many other research projects that ask for public assistance. Consider the Planet Hunters site at: http://www.planethunters.org/. What Planet Hunters aims to achieve is a more “hands-on” approach to interpreting the light curves from the publicly available data from the Kepler planet finding mission. Planet Hunters is part of the Zooniverse, which is a collection of citizen science projects. You can learn more about the complete collection of Zooniverse projects at: http://www.zooniverse.org
Another citizen science effort recently announced is the Pro-Am White Dwarf Monitoring (PAWM) project. Led by Bruce Gary, the goal of the project is to explore the possibility of using amateur and professional observers to estimate the percentage of white dwarfs exhibiting transits by Earth-size planets in the habitable zone. The results from such a survey are thought to be useful in planning a comprehensive professional search for white dwarf transits. You can read more about the PAWM project at: http://www.brucegary.net/WDE/
Transit simulation. Image Credit: Manuel Mendez/PAWM
One very long standing citizen project is the American Association of Variable Star Observers (AAVSO). Founded in 1911, the AAVSO coordinates, evaluates, compiles, processes, publishes, and disseminates variable star observations to the astronomical community throughout the world. Currently celebrating their 100th year, the AAVSO not only provides raw data, but also publishes The Journal of the AAVSO, a peer-reviewed collection of scientific papers focused on variable stars. In addition to data and peer reviewed journals, the AAVSO is active in education and outreach, with many programs, including their mentor program designed to assist with disseminating information to educators and the public.
If you’d like to learn more about the AAVSO, including membership information, visit their site at: http://www.aavso.org/
For over a decade, space enthusiasts across the internet have been taking part in SETI@Home. The official description of SETI@home is “a scientific experiment that uses Internet-connected computers in the Search for Extraterrestrial Intelligence (SETI)”. By downloading special client software from the SETI@Home website at http://setiathome.berkeley.edu/, volunteers from around the world can help analyze radio signals and assist with SETI’s efforts to find “candidate” radio signals. You can learn more about SETI@Home by visiting http://setiathome.berkeley.edu/sah_about.php
The projects and efforts featured above are just a small sample of the many projects that non-scientists can participate in. There are many other projects involving radio astronomy, galaxy classification, exoplanets, and even projects involving our own solar system. Volunteers of all ages and educational backgrounds can easily find a project to help support.
Ray Sanders is a Sci-Fi geek, astronomer and space/science blogger. Visit his website Dear Astronomer and follow on Twitter (@DearAstronomer) or Google+ for more space musings.
The AstroClip™ is a simple mount that attaches your iPhone onto any telescope. Credit: Matthew Geyster.
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They say necessity is the mother of invention, and if you’ve ever tried to take a picture through a telescope with your iPhone you’ll understand the necessity behind this invention: the AstroClip, an ingenious bit of injection-molded awesomeness that mounts an iPhone 4 onto any standard 1.25″ telescope eyepiece, keeping it stable and centered with the camera lens. I think this is a great idea and would certainly get one… that is, if it actually becomes a reality.
The AstroClip is designed to be very minimal while still being fully functional.
Invented by Boston designer Matthew Geyster, the AstroClip (patent pending) is still in development stage right now, awaiting the funding to go into production. Injection molding is a “simple but very expensive” process and in order to get the AstroClip produced Geyster has put his project up on Kickstarter, a web site that lets people pitch their great ideas that need funding and gives them a timeline to gather pledges.
If the AstroClip project can accumulate $15,000 in pledges by September 3, it will go into production. At the time of this writing there are 38 days left until then and it’s only 10% toward its goal. I’m hoping that drawing some more attention to this cool idea will help it along!
By becoming a “backer” you can pledge in several denomination categories, ranging from $1 or more to $500 or more. Each category above $25 comes with a “reward” of some sort… these are all listed on the project page.
I think Matthew has a great concept here. The camera on the iPhone 4 is very good and could take some great shots of the Moon and other astronomical objects, were it to just have a secure mount on a telescope lens. I’ve tried to do it without a mount before and really, it’s not easy.
Moon image taken with an iPhone and AstroClip
“The AstroClip is designed to be very minimal, while still being fully functional. The clip is very simple and rigid to hold your iPhone 4 steady and securely for the perfect shot. I also added the three adjustment screws that look like they’re meant to be on a telescope. With the simplicity and functionality of the AstroClip you will be taking great photos of outer space in no time at all.”
– Matthew Geyster
Honestly, I have no connection personally with this project or with Matthew… I just think this is something that would be very popular with iPhone users and astronomy enthusiasts. (I don’t even have a telescope… the light pollution in my city is pretty bad.) I just liked the idea so much I wanted to help support it however I could, and Universe Today seemed the perfect place to call attention to it!
If it proceeds the AstroClip will be entirely produced in the USA. Check it out on Kickstarter by clicking the image above or visit theastroclip.com.
Jason Major is a graphic designer, photo enthusiast and space blogger. Visit his websiteLights in the Dark and follow him on Twitter @JPMajor or on Facebook for the most up-to-date astronomy news and images!
For astronomers and physicists alike, the depths of space are a treasure trove that may provide us with the answers to some of the most profound questions of existence. Where we come from, how we came to be, how it all began, etc. However, observing deep space presents its share of challenges, not the least of which is visual accuracy.
In this case, scientists use what is known as Active Optics in order to compensate for external influences. The technique was first developed during the 1980s and relied on actively shaping a telescope’s mirrors to prevent deformation. This is necessary with telescopes that are in excess of 8 meters in diameter and have segmented mirrors.
Definition:
The name Active Optics refers to a system that keeps a mirror (usually the primary) in its optimal shape against all environmental factors. The technique corrects for distortion factors, such as gravity (at different telescope inclinations), wind, temperature changes, telescope axis deformation, and others.
The twin Keck telescopes shooting their laser guide stars into the heart of the Milky Way on a beautifully clear night on the summit on Mauna Kea. Credit: keckobservatory.org/Ethan
Adaptive Optics actively shapes a telescope’s mirrors to prevent deformation due to external influences (like wind, temperature, and mechanical stress) while keeping the telescope actively still and in its optimal shape. The technique has allowed for the construction of 8-meter telescopes and those with segmented mirrors.
Use in Astronomy:
Historically, a telescope’s mirrors have had to be very thick to hold their shape and to ensure accurate observations as they searched across the sky. However, this soon became unfeasible as the size and weight requirements became impractical. New generations of telescopes built since the 1980s have relied on very thin mirrors instead.
But since these were too thin to keep themselves in the correct shape, two methods were introduced to compensate. One was the use of actuators which would hold the mirrors rigid and in an optimal shape, the other was the use of small, segmented mirrors which would prevent most of the gravitational distortion that occur in large, thick mirrors.
The New Technology Telescope (NTT) pioneered the Active Optics. Credit: ESO/C.Madsen. Bacon
Other Applications:
In addition to astronomy, Active Optics is used for a number of other purposes as well. These include laser set-ups, where lenses and mirrors are used to steer the course of a focused beam. Interferometers, devices which are used to emit interfering electromagnetic waves, also relies on Active Optics.
These interferometers are used for the purposes of astronomy, quantum mechanics, nuclear physics, fiber optics, and other fields of scientific research. Active optics are also being investigated for use in X-ray imaging, where actively deformable grazing incidence mirrors would be employed.
Adaptive Optics:
Active Optics are not to be confused with Adaptive Optics, a technique that operates on a much shorter timescale to compensate for atmospheric effects. The influences that active optics compensate for (temperature, gravity) are intrinsically slower and have a larger amplitude in aberration.
Artist’s impression of the European Extremly Large Telescope deploying lasers for adaptive optics. Credit: ESO/L. Calçada/N. Risinger
On the other hand, Adaptive Optics corrects for atmospheric distortions that affect the image. These corrections need to be much faster, but also have smaller amplitude. Because of this, adaptive optics uses smaller corrective mirrors (often the second, third or fourth mirror in a telescope).
Do you have a new telescope, or are you considering buying a new one? Hopefully, you have chosen a telescope with the best specifications for your budget, but before you can truly get the best out of your wonderful new window on the cosmos, you need to have something even more important than the scope – Eyepieces!
A lot of people new to astronomy, or new to buying astronomy equipment tend to concentrate on telescopes and unfortunately overlook eyepieces, settling for the basic set of 2 or 3 that come with the new telescope.
Eyepieces are probably the most important part of your observing equipment, as they are at the heart of your setup and can make your observing experience fantastic or disastrous, or make an average telescope great or an excellent telescope bad.
The Basics
Eyepieces are the part you look through and are responsible for magnification of the objects you see through the telescope. They come in many different magnifications and types, but it’s not rocket science. You will soon learn what eyepieces work well for seeing different astronomical objects.
Telescope eyepieces are designed to fit into the focuser of the telescope. Depending on your telescope, they come in two sizes 1.25” or 2” and there is .965” which is an older size and pretty much obsolete, unless you have an old telescope. Most telescopes can be fitted with adapters so both eyepiece sizes can be used.
Magnification
The magnifying power of any eyepiece is a simple equation expressed in millimetres: Divide the focal length of the telescope by the focal length of the eyepiece and your answer is the amount of magnification. Long focal length eyepieces such as 32mm and 25mm are lower magnification, while lower numbers like 10mm and 5mm are magnifying powerhouses.
It is always good practice to start observing an object with a lower power eyepiece such as a 40mm and gradually build up to higher powered eyepieces such as 10mm or lower. The reason for this is the telescope, human eye, seeing conditions and object being observed are all variable. Starting off with a high power such as 4.7mm may be a struggle.
Fainter objects such as nebula and galaxies are usually seen better with lower powers and you can really ramp up the power with bright objects like the moon.
Below are rough guides and are dependent on the telescope you use:
2mm-4.9mm Eyepieces: These are very high magnification and very difficult to use unless seeing conditions are perfect and the object observed is very bright, like the moon.
5mm – 6.9mm Eyepieces: These are good on bright objects such as the moon and bright planets, but are still very high power and work best with steady seeing conditions.
7mm – 9.9mm Eyepieces: These are very comfortable high magnification eyepieces and are excellent for observing brighter objects, a must for any eyepiece collection.
10mm – 13.9mm Eyepieces: These work well for all objects including brighter nebula and galaxies a good mid/high range magnification.
14mm – 17.9mm Eyepieces: These are a great mid range magnification and will help resolve globular clusters, galaxy details and planetary nebulae.
18mm – 24.9mm Eyepieces: These will work nicely to show wide field and extended objects, great mid-range magnification for objects like galaxy clusters and large open clusters.
25mm – 30.9mm Eyepieces: These are wider field eyepieces for large nebula and open clusters. A good finder eyepiece for locating objects before moving to higher powers.
31mm – 40mm Eyepieces: These are excellent for extended views and large star fields and make excellent finder eyepieces before moving to higher powers.
Eye Relief
Eye relief is the distance from the last surface of an eyepiece at which the eye can obtain the full viewing angle. If a viewer’s eye is outside this distance, a reduced field of view will be obtained and viewing the image through the eyepiece can be difficult. Generally longer eye relief is preferred.
Eye Relief Credit: qwiki.com
Apparent Field of View
This is the apparent size of the image in the eyepiece and can range from about 35 to 100 degrees. Larger fields of view are more desired.
Apparent Field of View Credit: starizona.com
Types of Eyepiece
There are many different eyepiece types, some old and now obsolete, some simple and some advanced.
The different types of eyepiece are purely governed by the configuration of the glass and lenses inside the eyepiece. Some giving exceptional eye relief, wide fields of view, colour correction etc.
Some different brands of eyepiece include: Huygens, Ramsden, Kellner, Plössl, Orthoscopic and Kellner.
The most common and popular eyepiece type is the Plössl due to its good all round performance, good eye relief, approximate 50 degree field of view, pinpoint sharpness and good contrast. Plössl eyepieces are made by many manufacturers now, but there are excellent examples from manufacturers such as Meade and Televue.
Finally we have exotic eyepieces such as Super Wide and Ultra Wide which are usually 2” eyepieces, with higher powers up to around 4.7mm at 1.25” and are usually in the domain of the large Dobsonian or Newtonian telescope user, but are just at home on smaller telescopes such as refractors or Cassegrains.
These eyepieces sport amazing eye relief and huge “port hole” 80 – 100 degree views with fully loaded premium optics, which are very forgiving on telescopes with optical aberrations and other problems. They can make average or poor telescopes great, but there is a cost; an example of which is my 14mm Ultra Wide which cost £500 ($800) just for one eyepiece and I have a full set! Combined, my eyepieces are worth much, much more than the telescopes they are used on, but it’s worth it!
Eyepieces are the most important part of your observing equipment, choose them and use them well, which will help you enjoy observing through your telescope.
Artist concept of matter swirling around a black hole. (NASA/Dana Berry/SkyWorks Digital)
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Imagine a spinning black hole so colossal and so powerful that it kicks photons, the basic units of light, and sends them careening thousands of light years through space. Some of the photons make it to Earth. Scientists are announcing in the journal NaturePhysics today that those well-traveled photons still carry the signature of that colossal jolt, as a distortion in the way they move. The disruption is like a long-distance missive from the black hole itself, containing information about its size and the speed of its spin.
The researchers say the jostled photons are key to unraveling the theory that predicts black holes in the first place.
“It is rare in general-relativity research that a new phenomenon is discovered that allows us to test the theory further,” says Martin Bojowald, a Penn State physics professor and author of a News & Views article that accompanies the study.
Black holes are so gravitationally powerful that they distort nearby matter and even space and time. Called framedragging, the phenomenon can be detected by sensitive gyroscopes on satellites, Bojowald notes.
Lead study author Fabrizio Tamburini, an astronomer at the University of Padova (Padua) in Italy, and his colleagues have calculated that rotating spacetime can impart to light an intrinsic form of orbital angular momentum distinct from its spin. The authors suggest visualizing this as non-planar wavefronts of this twisted light like a cylindrical spiral staircase, centered around the light beam.
“The intensity pattern of twisted light transverse to the beam shows a dark spot in the middle — where no one would walk on the staircase — surrounded by concentric circles,” they write. “The twisting of a pure [orbital angular momentum] mode can be seen in interference patterns.” They say researchers need between 10,000 and 100,000 photons to piece a black hole’s story together.
And telescopes need some kind of 3D (or holographic) vision in order to see the corkscrews in the light waves they receive, Bojowald said: “If a telescope can zoom in sufficiently closely, one can be sure that all 10,000-100,000 photons come from the accretion disk rather than from other stars farther away. So the magnification of the telescope will be a crucial factor.”
He believes, based on a rough calculation, that “a star like the sun as far away as the center of the Milky Way would have to be observed for less than a year. So it is not going to be a direct image, but one would not have to wait very long.”
Study co-author Bo Thidé, a professor and program director at the Swedish Institute of Space Physics, said a year may be conservative, even in the case of a small rotation and a need for up to 100,000 photons.
“But who knows,” he said. “We will know more after we have made further detailed modelling – and observations, of course. At this time we emphasize the discovery of a
new general relativity phenomenon that allows us to make observations, leaving precise quantitative predictions aside.”
Have you ever wondered what it would be like to look through a telescope, but don’t have one? Are you curious if there is such a thing as an online telescope? The answer is yes. If you have a computer, you can use it to virtually look through the eyepiece of a telescope… and even aim it at the objects of your choice!
One of the most exciting concepts to come about in a long time is the SLOOH Space Camera. Here’s an opportunity to look through a variety of online telescopes located around the world and take a look at space from the comfort of your home. It’s not difficult and you don’t need complicated instructions to use it. SLOOH’s patented instant-imaging technology and user-friendly interface let’s astronomers of all ages and skill levels remotely control a real telescope!All you need is a Mac or PC computer and Internet browser to explore the deepest reaches of space. To use the Slooh online telescope you must become a member of the Club, which includes mission cards, activity books, and online gift certificates. Once enrolled, you can articipate in group missions or control the online telescopes yourself. Says PC Magazine: “Would-be astronomers can gaze at live images of the night sky, but in the comfort of their homes. Kids – even big ones will marvel when they see the Andromeda Galaxy and other distant objects slowly materialize on their computer screens.”
If you’re a bit more advanced and would like to try your hand at astrophotograpy with an online telescope, then check out iTelescope.Net. iTelescope.Net also has a variety of telescopes positioned in observatories around the world, and you can view live images as they are being created by remote astrophographers. Because taking images of the sky can involve very costly equipment and years of practice, how cool would it be just to tap into an on-line telescope and begin imaging? Now it’s as easy as taking lessons and renting the equipment – and you don’t even need clear skies or a special place to go. It’s as close as your PC!
Another type of opportunity to enjoy an online telescope in a different format is the WorldWide Telescope. While this online telescope doesn’t offer “live” views, the WorldWide Telescope (WWT) will allow your computer to act as a virtual telescope by displaying images from the foremost ground and space-based telescopes. You can even take a tour of all the most incredible places in space narrated by a real astronomer! This online telescope can provide views in multiple wavelength. Imagine seeing an x-ray view of a supernova and fading into visible light! Now you can take a look with H-alpha to view star-forming regions and examine high energy radiation coming from nearby stars in the Milky Way. Are you skies clouded out? No more. With the WorldWide Telescope you can view the Moon and planets anytime, from any location on Earth and any time in the past or future!
Would you like to use an online telescope to look at our nearest star? Then take a look at Eyes On The Skies. This simple and easy to use website offers “live” views of our Sun with an online telescope. This is the home of the internet-accessible robotic solar telescope, built by Tri-Valley Stargazers member Mike Rushford. Of course, you can only control the online solar telescope if the skies are sunny in Livermore California, USA!
I’ve had a couple of readers write me, wondering what was going on with all the Celestron telescope reviews. Are we sponsored by Celestron, or something? Nope. Let me just make this clear. We don’t get any money from any of the telescope manufacturers, or any kind of sponsorship at all. If and when we do, I’ll let you know.
So far, Celestron, Vixen and Sky Watcher are the only telescope manufacturers willing to send out a telescope for us to review, and then willing to pay for the return shipping to take it back off our hands again. If I have to pay to receive a telescope, or ship it back, we can’t afford to review it on Universe Today.
I know that really sets the bar pretty low. Universe Today received almost 2 million visitors last month, with 50,000 people subscribed to the RSS feed and daily email newsletter. Many of them are very interested in owning a telescope and would love to read about all the telescopes on the market. But I’m honestly exhausted trying to justify this to the manufacturers.
But so we’re clear, we’re not paid to give Celestron good reviews. If Tammy comes across as kind of enthusiastic in her reviews, well… that’s Tammy; she’s an enthusiastic force of nature. The manufacturers pay to ship the telescopes to and from our reviewers (well, Tammy), and then I pay Tammy for her reviews. If the telescope companies advertise on Universe Today, through Google, or through direct advertising, it doesn’t influence what Tammy has to say about them.
And if you’re a telescope manufacturer who wants to join this elite club of companies getting reviews on Universe Today, you just need to pay for the shipping. And if you want to advertise on Universe Today, just drop me an email.
P.S. I picked up a Celestron First Scope for the, uh, kids, and I really like it. Thanks to Tammy for the review, and thanks to the IYA for helping get it built.
This artist's conception shows the newly discovered super-Earth GJ 1214b, which orbits a red dwarf star 40 light-years from our Earth. Credit: Credit: David A. Aguilar, CfA
This artist’s conception shows the newly discovered super-Earth GJ 1214b, which orbits a red dwarf star 40 light-years from our Earth. Credit: Credit: David A. Aguilar, CfA
More exoplanets this week! Today astronomers announced the discovery of so called super-Earth around a nearby, low-mass star, GJ1214. The newly discovered planet has a mass about six times that of Earth and 2.7 times its radius, falling in between the size of Earth and the ice giants of the Solar System, Uranus and Neptune. But this latest exoplanet, GJ1214b, has something else, too: an atmosphere about 200 km thick. “This atmosphere is much thicker than that of the Earth, so the high pressure and absence of light would rule out life as we know it,” said David Charbonneau, lead author of a paper in Nature reporting the discovery, “but these conditions are still very interesting, as they could allow for some complex chemistry to take place.”
GJ1214b is also a very hot place to be. It orbits its star once every 38 hours at a distance of only two million kilometres — 70 times closer to its star than the Earth is to the Sun. “Being so close to its host star, the planet must have a surface temperature of about 200 degrees Celsius, too hot for water to be liquid,” said Charbonneau.
However, another member of the team said water ice could possibly be present on GJ1214b, deep inside the heart of the planet. “Despite its hot temperature, this appears to be a waterworld,” said graduate Zachory Berta who first spotted the hint of the planet among the data. “It is much smaller, cooler, and more Earth-like than any other known exoplanet.”
The star is a small, red type M star about one-fifth the size of our Sun. It has a surface temperature of only about 2,700 C (4,900 degrees F) and a luminosity only three-thousandths as bright as the Sun.
Artist impression of how the newly discovered super-Earth surrounding the nearby star GJ1214 may look. Credit: ESO/L. Calçada
Charbonneau compared this new exoplanet to Corot-7b, the first rocky super-Earth found using the transit method, when the planet’s orbit is takes it across the face of its parent star, from our vantage point. .
The astronomers were also able to obtain the mass and radius of GJ1214b, allowing them to determine the density and to infer the inner structure.
Although the mass of GJ1214b is similar to that of Corot-7b, its radius is much larger, suggesting that the composition of the two planets must be quite different. While Corot-7b probably has a rocky core and may be covered with lava, astronomers believe that three quarters of GJ1214b is composed of water ice, the rest being made of silicon and iron.
“The differences in composition between these two planets are relevant to the quest for habitable worlds,” said Charbonneau. “If super-Earth planets in general are surrounded by an atmosphere similar to that of GJ1214b, they may well be inhospitable to the development of life as we know it on our own planet.”
The atmosphere was detected when the astronomers compared the measured radius of GJ1214b with theoretical models of planets. They found that the observed radius exceeds the models’ predictions, and deduced that a thick atmosphere was blocking the star’s light.
“Because the planet is too hot to have kept an atmosphere for long, GJ1214b represents the first opportunity to study a newly formed atmosphere enshrouding a world orbiting another star,” said Xavier Bonfils, another member of the team. “Because the planet is so close to us, it will be possible to study its atmosphere even with current facilities.”
The planet was first discovered as a transiting object within the MEarth project, which follows about 2000 low-mass stars to look for transits by exoplanets, and uses a fleet of eight small, (16-inch) amateur-sized ground-based telescopes.
To confirm the planetary nature of GJ1214b and to obtain its mass (using the so-called Doppler method), the astronomers needed the full precision of the HARPS spectrograph, attached to ESO’s 3.6-metre telescope at La Silla.
The next step for astronomers is to try to directly detect and characterize the atmosphere, which will require a space-based instrument like NASA’s Hubble Space Telescope. GJ1214b is only 40 light-years from Earth, within the reach of current observatories.
The European Southern Observatory (ESO) is planning on building a massive – and I do mean massive – telescope in the next decade. The European Extremely Large Telescope (E-ELT) is a 42-meter telescope in its final planning stages. Weighing in at 5,000 tonnes, and made up of 984 individual mirrors, it will be able to image the discs of extrasolar planets and resolve individual stars in galaxies beyond the Local Group! By 2018 ESO hope to be using this gargantuan scope to stare so deep into space that they can actually see the Universe expanding!
The E-ELT is currently scheduled for completion around 2018 and when built it will be four times larger than anything currently looking at the sky in optical wavelengths and 100 times more powerful than the Hubble Space Telescope – despite being a ground-based observatory.
With advanced adaptive optics systems, the E-ELT will use up to 6 laser guide stars to analyse the twinkling caused by the motion of the atmosphere. Computer systems move the 984 individual mirrored panels up to a thousand times a second to cancel out this blurring effect in real time. The result is an image almost as crisp as if the telescope were in space.
This combination of incredible technological power and gigantic size mean that that the E-ELT will be able to not only detect the presence of planets around other stars but also begin to make images of them. It could potentially make a direct image of a Super Earth (a rocky planet just a few times larger than Earth). It would be capable of observing planets around stars within 15-30 light years of the Earth – there are almost 400 stars within that distance!
The E-ELT will be able to resolve stars within distant galaxies and as such begin to understand the history of such galaxies. This method of using the chemical composition, age and mass of stars to unravel the history of the galaxy is sometimes called galactic archaeology and instruments like the E-ELT would lead the way in such research.
Incredibly, by measuring the redshift of distant galaxies over many years with a telescope as sensitive as the E-ELT it should be possible to detect the gradual change in their doppler shift. As such the E-ELT could allow humans to watch the Universe itself expand!
ESO has already spent millions on developing the E-ELT concept. If it is completed as planned then it will eventually cost about €1 billion. The technology required to make the E-ELT happen is being developed right now all over the world – in fact it is creating new technologies, jobs and industry as it goes along. The telescope’s enclosure alone presents a huge engineering conundrum – how do you build something the size of modern sports stadium at high altitude and without any existing roads? They will need to keep 5,000 tonnes of metal and glass slewing around smoothly and easily once it’s operating – as well as figuring out how to mass-produce more than 1200 1.4m hexagonal mirrors.
The E-ELT has the capacity to transform our view not only of the Universe but of telescopes and the technology to build them as well. It will be a huge leap forward in telescope engineering and for European astronomy it will be a massive 42m jewel in the crown.
