Posted on by Nancy Atkinson

Kepler Flips Its Lid; Soon Ready for Planet Hunt

Artist concept of the Kepler spacecraft's dust cover coming off. Image credit: NASA/JPL

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Engineers successfully ejected the dust cover from NASA’s Kepler telescope last night and the space observatory will soon begin searching for Earth-like planets. “The cover released and flew away exactly as we designed it to do,” said Kepler Project Manager James Fanson from JPL. “This is a critical step toward answering a question that has come down to us across 100 generations of human history — are there other planets like Earth, or are we alone in the galaxy?”

Click here for an animation of the event.

Kepler launched on March 6, 2009 and will spend at least three-and-a-half years staring at more than 100,000 stars in our Milky Way galaxy for signs of Earth-size planets. Some of the planets are expected to orbit in a star’s “habitable zone,” a warm region where water could pool on the surface. The mission’s science instrument, called a photometer, contains the largest camera ever flown in space — its 42 charge-coupled devices (CCDs) will detect slight dips in starlight, which occur when planets passing in front of their stars partially block the light from Kepler’s view.

The telescope’s oval-shaped dust cover, measuring 1.7 meters by 1.3 meters (67 inches by 52 inches), protected the photometer from contamination before and after launch. The dust cover also blocked stray light from entering the telescope during launch — light that could have damaged its sensitive detectors. In addition, the cover was important for calibrating the photometer. Images taken in the dark helped characterize noise coming from the instrument’s electronics, and this noise will later be removed from the actual science data.

“Now the photometer can see the stars and will soon start the task of detecting the planets,” said Kepler’s Science Principal Investigator William Borucki at NASA’s Ames Research Center, Moffett Field, Calif. “We have thoroughly measured the background noise so that our photometer can detect minute changes in a star’s brightness caused by planets.”

At 7:13 p.m. PDT on April 7, engineers at Kepler’s mission operations center at the Laboratory for Atmospheric and Space Physics, Boulder, Colo., sent commands to pass an electrical current through a “burn wire” to break the wire and release a latch holding the cover closed. The spring-loaded cover swung open on a fly-away hinge, before drifting away from the spacecraft. The cover is now in its own orbit around the sun, similar to Kepler’s sun-centric orbit.

Posted on by Anne Minard

Moon Reveals New Way to Find Oceans, Land on Other Earths

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An Australian doctoral researcher using a backyard telescope has made a potentially big discovery: Earth’s oceans and continents shine differently on the dark side of the moon.

Now, Sally Langford, a doctoral candidate in physics at the University of Melbourne, is suggesting the “earthshine” of planets around other stars could provide long-distance windows into their surface features.

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Langford's setup for moon observing. Credit: Stuart Wyithe, second author, also a physicist at the University of Melbourne.

Langford and her colleagues, from Melbourne as well as Princeton University, have shown for the first time that the difference in reflection of light from the Earth’s land masses and oceans can be seen on the dark side of the moon, a phenomenon known as earthshine. Their paper appears in this week’s edition of the international journal Astrobiology.

This is the first study in the world to use the reflection of the Earth to measure the effect of continents and oceans on the apparent brightness of a planet. Other studies have used a color spectrum and infrared sensors to identify vegetation, or for climate monitoring.

The researchers peered at the dark side of the crescent moon using a 20 cm (8 inch) telescope, on the bigger side of what most amateur astronomers use in their yards.

For three years, Langford took images of the Moon to measure the earth’s brightness as it rotated. Observations of the Moon were made from Mount Macedon in Victoria, for around three days each month when the Moon was rising or setting. The study was conducted so that in the evening, when the Moon was a waxing crescent, the reflected earthshine originated from Indian Ocean and Africa’s east coast. In the morning, when the Moon was a waning crescent, it originated only from the Pacific Ocean.

“When we observe earthshine from the Moon in the early evening we see the bright reflection from the Indian Ocean, then as the Earth rotates the continent of Africa blocks this reflection, and the Moon becomes darker,” Langford said.

Langford said the variation revealed the difference between the intense mirror-like reflections of the ocean compared to the dimmer land.

“In the future, astronomers hope to find planets like the Earth around other stars,” Langford said. “However these planets will be too small to allow an image to be made of their surface. We can use earthshine, together with our knowledge of the Earth’s surface, to help interpret the physical makeup of new planets.” 

LEAD IMAGE CAPTION: Earthshine on a crescent moon. Credit: Edward W. Szczepanski, Houston Astronomical Society (click on the photo to visit Szczepanski’s page)

Source: University of Melbourne. The paper is available here.

Posted on by Nancy Atkinson

JWST Will Provide Capability to Search for Biomarkers on Earth-like Worlds

This artist's conception shows a hypothetical twin Earth orbiting a Sun-like star. A new study shows that characterizing a distant Earth's atmosphere will be difficult, even using next-generation technology like the James Webb Space Telescope. If an Earth-like world is nearby, though, then by adding observations of a number of transits, astronomers should be able to detect biomarkers like methane or ozone. Credit: David A. Aguilar (CfA)

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Does another Earth exist somewhere in our galaxy? With the recent lauch of the Kepler spacecraft, astronomers are getting closer and closer to finding an Earth-sized planet in an Earth-like orbit. But once that search succeeds, the next questions driving research will be: Is that planet habitable? Does it have an Earth-like atmosphere? Answering those questions will not be easy. But the telescope up for the task is the James Webb Space Telescope (JWST), set for a planned launch in 2013. Two researchers recently examined the ability of JWST to characterize the atmospheres of hypothetical Earth-like planets, and found this is the telescope that would be able to detect certain gases called biomarkers, such as ozone and methane, for close Earth-size worlds. (See our related article: Q&A with Dr. John Mather on JWST.)

Due to its large mirror and location at the L2 point in outer space, the James Webb Space Telescope will offer astronomers the first real possibility of finding the answers about the habitability of nearby Earth-like worlds, say Lisa Kaltenegger from the Harvard-Smithsonian Center for Astrophysics and Wesley Traub from the Jet Propulsion Laboratory. “We’ll have to be really lucky to decipher an Earth-like planet’s atmosphere during a transit event so that we can tell it is Earth-like,” said Kaltenegger. “We will need to add up many transits to do so – hundreds of them, even for stars as close as 20 light-years away.”

“Even though it’s hard, it will be an incredibly exciting endeavor to characterize a distant planet’s atmosphere,” she added.

In a transit event, a distant, extrasolar planet crosses in front of its star as seen from Earth. As the planet transits, gases in its atmosphere absorb a tiny fraction of the star’s light, leaving fingerprints specific to each gas. By splitting the star’s light into a rainbow of colors or spectrum, astronomers can look for those fingerprints. Kaltenegger and Traub studied whether those fingerprints would be detectable by JWST.

The transit technique is very challenging. If Earth were the size of a basketball, the atmosphere would be as thin as a sheet of paper, so the resulting signal is incredibly tiny. Moreover, this method only works when the planet is in front of its star, and each transit lasts for a few hours at most.

Artists concept of the JWST in space. Credit: NASA
Artists concept of the JWST in space. Credit: NASA

Kaltenegger and Traub first considered an Earth-like world orbiting a Sun-like star. To get a detectable signal from a single transit, the star and planet would have to be extremely close to Earth. The only Sun-like star close enough is Alpha Centauri A. No such world has been found yet, but technology is only now becoming capable of detecting Earth-sized worlds.

The study also considered planets orbiting red dwarf stars. Such stars, called type M, are the most abundant in the Milky Way – far more common than yellow, type G stars like the Sun. They are also cooler and dimmer than the Sun, as well as smaller, which makes finding an Earth-like planet transiting an M star easier.

An Earth-like world would have to orbit close to a red dwarf to be warm enough for liquid water. As a result, the planet would orbit more quickly and each transit would last a couple of hours to mere minutes. But it would undergo more transits in a given amount of time. Astronomers could improve their chances of detecting the atmosphere by adding the signal from several transits, making red dwarf stars appealing targets because of their more frequent transits.

An Earth-like world orbiting a star like the Sun would undergo a 10-hour transit once every year. Accumulating 100 hours of transit observations would take 10 years. In contrast, an Earth orbiting a mid-sized red dwarf star would undergo a one-hour transit once every 10 days. Accumulating 100 hours of transit observations would take less than three years.

“Nearby red dwarf stars offer the best possibility of detecting biomarkers in a transiting Earth’s atmosphere,” said Kaltenegger.

“Ultimately, direct imaging – studying photons of light from the planet itself – may prove a more powerful method of characterizing the atmosphere of Earth-like worlds than the transit technique,” said Traub.

Direct studies have already been used to create crude temperature maps of extremely hot, giant extrasolar planets. With next-generation instruments, astronomers may be able to study atmospheric compositions, not just temperatures. The characterization of a “pale blue dot” is the next step from there, whether by adding up hundreds of transits of one planet or by blocking out the starlight and analyzing the planet’s light directly.

In a best-case scenario, Alpha Centauri A may turn out to have a transiting Earth-like planet that no one has spotted yet. Then, astronomers would need only a handful of transits to decipher that planet’s atmosphere and possibly confirm the existence of the first twin Earth.

Source: Harvard Center For Astrophysics

Posted on by Ian O'Neill

Looking For Extraterrestrials Looking At Us

If there are habitable planets out there, where do we look?

[/caption]The cosmos is a very big place, how do you begin the search for exoplanets orbiting other stars? Astronomers have a few tricks up their sleeves to work out how to spot these tiny specks of distant alien worlds. Astronomers can look for the gravitational “wobble” of a star as a massive exoplanet tugs on its parent star during orbit, or more commonly, they look for the slight dimming of star light as the exoplanet passes in front of the star. In fact, the Kepler space telescope is going to peer into space, surveying 100,000 stars to do just this; not looking for large gas giants, but detecting rocky bodies that resemble large Earths with the unparalleled precision.

OK, so we have a means of finding these habitable worlds, how can we use this information to widen our search for extraterrestrial intelligence? Researchers in Israel have asked that same question, and arrived at a very logical answer. If we are to communicate with these advanced beings, perhaps we should make sure they can see us first…

The concept is simple enough. Find a star with an Earth-like transiting exoplanet (we will hopefully have a few super-Earth targets over the next three years with Kepler), aim a radio transmitter at the star and send a “Hello world!” message to the possible alien civilization living on the exoplanet. All going well (or not, depending on whether these extraterrestrials are actually friendly), we’ll get a reply from said star system in a few decades with a message saying something like “Hello world to you too!”. It would be a momentous day for interstellar communications and it would answer the one question that bugs astronomers everywhere: Are we alone in the cosmos?

So far so good, until interstellar travel becomes a reality, mankind and our new chatty alien neighbours can play a very long game of radio tag, learning more about each other as the years/decades/centuries go on (depending on how distant the extraterrestrial civilization is in the first place). But there’s a problem with this plan. What if our ET neighbours aren’t looking in our direction? What if the Sun looks like ‘just another’ star amongst the other 1010 Sun-like stars hanging out in the Milky Way? We can transmit to our hearts content, but they may never see us.

Shmuel Nussinov at Tel Aviv University in Israel asked these same questions and actually makes the search for extraterrestrial intelligence a little bit easier. With the assumption that a sufficiently advanced alien race is surveying the skies, also looking out for exoplanets orbiting other stars, they may be using the same transit method that we use to detect exoplanets. Therefore, it only seems reasonable that ET will only be able to detect Earth if we pass in front of the Sun, thus dimming it slightly for our alien neighbours to see us. If this is the case, it seems highly unlikely that any alien race will detect our existence unless they are located along a narrow angle along the ecliptic plane of our Solar System. So, if we want to open up some alien banter, we should perhaps send signals to Earth-like exoplanets spotted along the ecliptic.

Although the Earth only passes across the solar disk for 13 hours every year (as viewed by a distant observer), our star will appear to dim slightly, allowing ET to see us. Factor in the various transits of the inner Solar System planets, and our observers will see there are a few possibly habitable rocky “exoplanets” for them to transmit to. If we are already transmitting, communications can be exchanged.

What a good idea…

Source: arXiv blog

Posted on by Anne Minard

Success: Kepler Lifts Off to Look for Other Earths

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Kepler as it appeared moments prior to launch in Florida. Credit: NASA

NASA’s Kepler mission lifted off without a hitch just before 11 p.m. local time Friday from Cape Canaveral Air Force Station in Florida. 

The launch was a bit of a nail-biter, coming on the heels of last week’s failure of the Orbiting Carbon Observatory, which plummeted into the ocean when its fairing malfunctioned. But everything for the Kepler launch — from the weather to the countdown — went flawlessly. At five minutes to launch, Kepler’s rockets sent ribbons of smoke into Florida’s 65-degree Fahrenheit (18-degree Celsius) nighttime air under perfectly clear skies. With 30 seconds left, confirmation commands were exchanged with practiced precision. The casing (called the fairing) fell off with grace, and three minutes into the flight, the craft was cruising away from Earth at nearly 7,000 miles (11,265 kilometers) per hour. Each launch event happened within three seconds of its predicted time. 

Kepler’s engines shut down at 11:45 p.m. U.S. eastern time, and the craft achieved separation just before midnight, about 62 minutes after launch. Now, for the next three and a half years, Kepler will trail Earth in orbit and stare at a single patch of sky in the  Cygnus-Lyra region of the Milky Way.

Kepler fires the imagination, as it could finally address the age-old question of whether we Earthlings are alone. William Borucki, NASA’s principal investigator for Kepler science, spoke about the mission at a recent NASA press conference and said if Kepler spies Earth-like planets in the habitable zones of other stars, “life may well be common throughout our universe. If on the other hand we don’t find any, that will be another profound discovery. In fact it will mean there will be no Star Trek.”

The $500 million Kepler mission will spend three and a half years surveying more than 100,000 sun-like stars in Cygnus-Lyra.  Its telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by. 

By staring at one large patch of sky for the duration of its lifetime, Kepler will be able to watch planets periodically transit their stars over multiple cycles, allowing astronomers to confirm the presence of planets and use the Hubble and Spitzer space telescopes, along with ground-based telescopes, to characterize their atmospheres and orbits. Earth-size planets in habitable zones would theoretically take about a year to complete one orbit, so Kepler will monitor those stars for at least three years to confirm the planets’ presence.

Astronomers estimate that if even one percent of stars host Earth-like planets, there would be a million Earths in the Milky Way alone. If that’s true, hundreds of Earths should exist in Kepler’s target population of 100,000 stars.

Posted on by Ian O'Neill

New Technique Allows Astronomers to Discover Exoplanets in Old Hubble Images

Using a new imaging technique on an 11 year old Hubble observation, an exoplanet has been discovered orbiting the young star HR 8799 (NASA/HST)

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The Hubble Space Telescope has recently provided us with some astonishing images of exoplanets orbiting distant stars. This is a departure from the indirect detection of exoplanets by measuring the “wobble” of stars (revealing the gravitational presence of a massive planetary body) or the transit of exoplanets through the line of sight of the parent star (causing its brightness to dim). Scientists have refined Hubble’s exoplanet hunting abilities to directly image these alien worlds in visible light. However, astronomers now have another trick to find these mysterious worlds. A new imaging technique is allowing us to see exoplanets already hiding in archival Hubble data…

It has been estimated that another 100 previously unknown exoplanets could be discovered in old Hubble data. The technique being tested by astronomers at the University of Toronto could be a very powerful new way to reveal the existence of a huge number of buried jewels buried by the glare of star light.

In November 2008, a spate of direct imagery of exoplanets showed the world how advanced our ground and space-based observatories were becoming. One such discovery was an observing campaign of the young star HR 8799 by the near-infrared adaptive optics observations of the Gemini and Keck telescopes. HR 8799 (140 light years away, approximately 50% more massive than our Sun) plays host to three massive gas giants (10, 10 and 7 times the size of Jupiter). Now that HR 8799 is known to have large exoplanets orbiting around it, the University of Toronto astronomers, headed by David Lafrenière, have re-examined images taken by Hubble of that same star in 1998, to see if there is any trace of these exoplanets in the old data. In 1998, HR 8799 appeared to be a lonely star, with no associated exoplanets.

Using a new technique to extract the weak exoplanet emission in the Hubble image, Lafrenière’s team have been able to cut down the glare of the parent star to reveal the presence of the outermost exoplanet of the trio known to be orbiting HR 8799 (pictured top). The other two exoplanets remain too close to the star to be resolved.

The University of Toronto result “definitely indicates that we should reanalyze all the existing Hubble images of young stars with the new approach — there’s probably 100 to 200 stars where planets could be seen,” comments planet-hunter Bruce Macintosh of the Lawrence Livermore National Laboratory in California. Many of these stars have already been studied by the powerful Keck observatory in Hawaii, so astronomers now have an exciting and powerful new analysis tool to hopefully reveal more overlooked exoplanets.

However, this most recent result was achieved by using a space-based observatory, as some of the near-infrared emission from the exoplanet will be absorbed by the Earth’s atmosphere.

The new exoplanet discovery potential has excited many astronomers, and it has highlighted the importance of maintaining a good archive of astronomical observations. “The first thing it tells you is how valuable maintaining long-term archives can be. Here is a major discovery that’s been lurking in the data for about 10 years!” said Matt Mountain, director of the Space Telescope Science Institute in Baltimore. “The second thing its tells you is having a well calibrated archive is necessary but not sufficient to make breakthroughs — it also takes a very innovative group of people to develop very smart extraction routines that can get rid of all the artifacts to reveal the planet hidden under all that telescope and detector structure.”

Hopefully we’ll be seeing even more exoplanet discoveries over the coming months, not just from new observing campaigns, but possibly from old observations using archived observatory data. Exciting times!

Source: Science News

Posted on by Ian O'Neill

Powerful Fusion Laser to Recreate Conditions Inside Exoplanets

A powerful laser could create the conditions inside a giant exoplanet (Sunbeamtech)

[/caption]We’ve all heard that the Large Hadron Collider (LHC) will collide particles together at previously unimaginable energies. In doing so, the LHC will recreate the conditions immediately after the Big Bang, thereby allowing us to catch a glimpse of what particles the Universe would have been filled with at this time. In a way, the LHC will be a particle time machine, allowing us to see the high energy conditions last seen immediately after the Big Bang, 13.7 billion years ago.

So, if we wanted to understand the conditions inside a giant exoplanet, how could we do it? We can’t directly measure it ourselves, we have to create a laboratory experiment that could recreate the conditions in the core of one of these huge exoplanet gas giants. Much like the LHC will recreate the conditions of the Big Bang, a powerful laser intended to kick-start fusion reactions will be used in an effort to help scientists have a very brief look into the cores of these distant worlds…

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory in California is ready for action. The facility will perform fusion experiments, hopefully making a self-sustaining nuclear fusion reaction a reality using an incredibly powerful laser (firing at a hydrogen isotope fuel). Apart from the possibility of finding a way to kick-start a viable fusion energy source (other laboratories have tried, but only sustained fusion for an instant before fizzing out), the results from the laser tests will aid the management of the US nuclear weapon stockpile (since there have been no nuclear warhead tests in 15 years, data from the experiments may help the military deduce whether or not their bombs still work).

Fusion energy and nuclear bombs to one side, there is another use for the laser. It could be used to recreate the crushing pressures inside a massive exoplanet so we can glean a better understanding of what happens to matter at these crushing depths.

The NIF laser can deliver 500 trillion watts in a 20-nanosecond burst, which may not sound very long, but the energy delivered is immense. Raymond Jeanloz, an astronomer at the University of California, Berkeley, will have the exciting task of using the laser, aiming it at a small iron sample (800 micrometres in diameter), allowing him to generate a moment where pressures exceed a billion times atmospheric pressure. That’s 1000 times the pressure of the centre of the Earth.

On firing the laser, the heat will vaporize the iron, blasting a jet of gas so powerful, it will send a shock wave through the metal. The resulting compression is what will be observed and measured, revealing how the metal’s crystalline structure and melting point change at these pressures. The results from these tests will hopefully shed some light on the formation of the hundreds of massive exoplanets discovered in the last two decades.

“The chemistry of these planets is completely unexplored,” says Jeanloz. “It’s never been accessible in the laboratory before.”

Now that is one impressive laboratory experiment…

Source: New Scientist

Posted on by Anne Minard

NASA’s Kepler Mission Ready for Launch

Technicians working inside the Astrotech Space Operations facility near NASA's Kennedy Space Center look over the Kepler spacecraft soon after it arrived in Florida in preparation for launch. Image credit: NASA/Tim Jacobs

 

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NASA’s Kepler spacecraft is ready to be moved to the launch pad today and will blast off within weeks, with a mission to address an age-old question: Are we alone?

Kepler is scheduled to blast into space from Florida’s Cape Canaveral Air Force Station aboard a Delta II rocket on March 5 at 10:48 p.m. eastern time (7:48 p.m. Pacific). It is the first mission with the ability to find planets like Earth — rocky planets that orbit sun-like stars in a warm zone where liquid water could be maintained on the surface. If Earth-sized and slightly larger planets are as common around other stars as some astronomers suspect, Kepler could spy hundreds of them within the next few years.

If so, “life may well be common throughout our universe,” said William Borucki, NASA’s principal investigator for Kepler science, who spoke about the mission Thursday afternoon at a NASA press conference. “If on the other hand we don’t find any, that will be another profound discovery. In fact it will mean there will be no Star Trek.”

 

The Kepler mission will spend three and a half years surveying more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy.  Its telescope is specially designed to detect the periodic dimming of stars that planets cause as they pass by. Some star systems are oriented in such a way that their planets cross in front of their stars, as seen from our Earthly point of view. As the planets pass by, they cause their stars’ light to slightly dim, or wink.

The telescope can detect even the faintest of these winks, registering changes in brightness of only 20 parts per million. To achieve this resolution, Kepler will use the largest camera ever launched into space, a 95-megapixel array of charged couple devices, known as CCDs.

“If Kepler were to look down at a small town on Earth at night from space, it would be able to detect the dimming of a porch light as somebody passed in front,” James Fanson, Kepler project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a press release. During the briefing he added that the resolution is “akin to measuring a flea as it creeps across the headlight of an automobile at night. That’s the level of precision we have to achieve.”

Fanson added that Kepler, at a cost of about $500 million, is “the most complex piece of space flight hardware ever built” by the Boulder, Colorado-based Ball Aerospace & Technologies Corp.

The exoplanet research field has already proven exciting, Borucki said. Just over three hundred exoplanets have been detected so far, most of them gas giants like Jupiter and Saturn because those are the easiest to spot with pre-Kepler instruments. Already, the known exoplanets are an eclectic bunch.

“We’re finding planets that [would] float like foam on water,” Borucki said. “We’re finding planets with the density of lead.” And whereas researchers were expecting planet with orderly, circular orbits and sizes that increased with distances from stars, they’re finding a chaotic mix of behaviors — eccentric orbits, and giant, gaseous worlds so close to their parent stars that they complete full orbits within days.

By staring at one large patch of sky for the duration of its lifetime, Kepler will be able to watch planets periodically transit their stars over multiple cycles, allowing astronomers to confirm the presence of planets and use the Hubble and Spitzer space telescopes, along with ground-based telescopes, to characterize their atmospheres and orbits. Earth-size planets in habitable zones would theoretically take about a year to complete one orbit, so Kepler will monitor those stars for at least three years to confirm the planets’ presence.

The first objects likely to be reported will be the Jupiter- and Saturn-sized planets, and gradually — as confirmations roll in and detections get more focused — Neptune and then Earth-sized detections will be more likely to emerge, said exoplanet hunter Debra Fischer of San Francisco State University in California, who is not directly involved with the mission.

“We have a good chance of finding Mars-size planets, and a possibility of finding Mercury-sized planets” with Kepler, she said. “We don’t think we can do better than that.”

The scientists are in no rush to announce new discoveries until they’re “bulletproof,” they said — which could translate into years of suspense for the world’s Trekkies.

“We don’t want to have false discoveries,” Borucki said. “We want to be sure when we say it’s an earth, its an earth.”

Source: NASA teleconference and press release.

Posted on by Nicholos Wethington

The Milky Way Could have Billions of Earths

Exoplanets like the Earth might be more common than we think. Image Credit: ESO

With the upcoming launch in March of the Kepler mission to find extrasolar planets, there is quite a lot of buzz about the possibility of finding habitable planets outside of our Solar System. Kepler will be the first satellite telescope with the capability to find Earth-size and smaller planets. At the most recent meeting of the American Association for the Advancement of Science (AAAS) in Chicago, Dr. Alan Boss is quoted by numerous media outlets as saying that there could be billions of Earth-like planets in the Milky Way alone, and that we may find an Earth-like planet orbiting a large proportion of the stars in the Universe.

“There are something like a few dozen solar-type stars within something like 30 light years of the sun, and I would think that a good number of those — perhaps half of them would have Earth-like planets. So, I think there’s a very good chance that we’ll find some Earth-like planets within 10, 20, or 30 light years of the Sun,” Dr. Boss said in an AAAS podcast interview.

Dr. Boss is an astronomer at the Carnegie Institution of Washington Department of Terrestrial Magnetism, and is the author of The Crowded Universe, a book on the likelihood of finding life and habitable planets outside of our Solar System.

“Not only are they probably habitable but they probably are also going to be inhabited. But I think that most likely the nearby ‘Earths’ are going to be inhabited with things which are perhaps more common to what Earth was like three or four billion years ago,” Dr. Boss told the BBC. In other words, it’s more likely that bacteria-like lifeforms abound, rather than more advanced alien life.

This sort of postulation about the existence of extraterrestrial life (and intelligence) falls under the paradigm of the Drake Equation, named after the astronomer Frank Drake. The Drake Equation incorporates all of the variables one should take into account when trying to calculate the number of technologically advanced civilizations elsewhere in the Universe. Depending on what numbers you put into the equation, the answer ranges from zero to trillions. There is wide speculation about the existence of life elsewhere in the Universe.

To date, the closest thing to an Earth-sized planet discovered outside of our Solar System is CoRoT-Exo-7b, with a diameter of less than twice that of the Earth.

The speculation by Dr. Boss and others will be put to the test later this year when the Kepler satellite gets up and running. Set to launch on March 9th, 2009, the Kepler mission will utilize a 0.95 meter telescope to view one section of the sky containing over 100,000 stars for the entirety of the mission, which will last at least 3.5 years.

The prospect of life existing elsewhere is exciting, to be sure, and we’ll be keeping you posted here on Universe Today when any of the potentially billions of Earth-like planets are discovered!

Source: BBC, EurekAlert

Posted on by Anne Minard

Q&A with Kepler Scientist from — Iowa?

Artist's rendering of the Kepler Mission (NASA)

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With a target launch date of March 5, NASA’s Kepler mission is just weeks away from its tantalizing journey to peer at faraway stars and the Earth-like planets they may be hosting. Hundreds of astronomers from all over the world have a stake in the data. The United States participants hail from all the usual astronomy hubs, among them Arizona, California, Texas and … Iowa? Steve Kawaler, an astrophysicist at Iowa State University, took a moment to chat with Universe Today about his role in a less-publicized goal of the Kepler mission — and his research out of a less-publicized astronomy program.

Q. Why Iowa?

Kawaler: Iowa’s a great place. I’m originally a New Yorker, and went to grad school at the University of Texas, but landing at Iowa State (mostly by chance) still feels right. 

(Still Kawaler:) You can get a lot of work done here. We’ve organized and run the Whole Earth Telescope from here for about 10 years. A few years ago [in 2004], the WET team showed a pulsating white dwarf (BPM 37093, but later dubbed the ‘Diamond Star’) may truly be crystalline. Finding one of the biggest diamonds in the cosmos and announcing it around Valentine’s Day was pretty fun! I’ve been part of some big collaborations where nearly all the work is done remotely, and that is important as we stare at the mountain of data we’re about to see.

Q. What’s your role in the Kepler mission?

Kawaler: I serve on the Steering Committee for the Kepler Asteroseismology Research Consortium. We’ll use the exquisite time-series measurements of the brightness of over 100,000 stars to measure their internal properties.  The KASC has over 250 scientists involved, and the Steering Committee is charged with helping organize and coordinate their efforts in reducing and interpreting the data.

Q. What’s most exciting about the science in this mission?

Kawaler: The most exciting discovery will be the discovery of Earth-like planets around other stars. It’s what we all wonder about – are there other planets out there that host life?  That said, most of the stars that Kepler examines won’t show any signs of planetary transits … but the data will provide a gold mine of information about how stars behave. From the point of view of my own research, the most exciting thing that will come out will be improvement, by a factor of almost 100, in the measure of brightness of over 100,000 stars. Asteroseismologists are drooling at this prospect, because we expect to find oscillations in many stars, but this huge increase in sensitivity is bound to reveal new phenomena that we can’t even guess at yet. 

Q. A press release described part of your interest as “peering into stars.” Can you elaborate?

Kawaler: Until very recently, everything we know about stars, we learned from looking at the outsides. When you want to really need to know what’s going on, you need some sort of probe that goes beneath the surface.  For the Earth, seismic waves generated by earthquakes give you that kind of probe.  For stars, we have to measure their vibrations from (very!) far away.  Those vibrations produce only tiny signals — very subtle brightness variations. We can also look at how the surfaces move up and down and use those as a measure of the oscillations that are going on inside. Once we do make those measurements, we use the tools that terrestrial seismologists have developed, along with some of our own that are adapted to the special circumstances within stars, to probe the insides of the stars.

Q. Why can’t we do this work from Earth?

Kawaler: The short answer is that we can, sort of, but Earth is a really poor place to do this kind of work.  An astronomer can only look at a star for a couple hours a night before the star sets or the sun comes up. It’s kind of the equivalent of listening to Beethoven’s 5th Symphony and listening to every third note. You can sort of do it from the ground by putting together a network of telescopes.  We’ve had some remarkable successes.  But it’s much easier if you can observe from a platform that isn’t rotating. And if that platform is above the atmosphere, you get the added benefit of a direct line of sight to the star that doesn’t have the atmosphere degrading the image.  With continuous views and no atmosphere, Kepler can do way, way better than we can from the ground.

6. Is this helping to realize a life-long ambition for you?

Kawaler: Absolutely – I’ve always been a space program ‘geek.’ I grew up in the 60s. My older brother grew up in the 50s, and he got caught up in the whole Sputnik thing. There were all these books and toys about space; I picked them up and was instantly fascinated. Later, I was just riveted to the TV all the time, watching Gemini and the Apollo missions. I guess I still haven’t grown out of it. My brother is one of the few rabbis that dresses as Captain Kirk on Purim, Jewish Halloween, so I guess he didn’t grow out of it, either. I’m actually heading down to Florida for the launch, with my father, so he can finally be convinced I didn’t have to be a ‘real doctor’ — I can be a PhD.

Sources: Steve Kawaler, NASA

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Kepler's search space in the Milky Way, courtesy of NASA.