You are currently browsing the tag archive for the ‘Kepler’ tag.
During the last several years one of the most exciting aspects of astronomy has been data from two orbiting space observatories concerning planets which lie outside our solar system. The NASA space telescope Kepler discovers such planets by simultaneously measuring the light from thousands of stars for the faint dimming that occurs when a planet passes between the star and Kepler. The French satellite COROT (“COnvection ROtation and planetary Transits”) finds exoplanets by tracking the slight oscillations in distant stars caused by the gravitational tug of orbiting planets. The subtlety and elegant precision of both methods is astounding.
Sadly such astonishing engineering seems to have been near the edge of our technological abilities. Yesterday Kepler went into safe mode (a sort of automatic shut-down triggered by a crisis). Apparently a reaction wheel (a flywheel used to orient the spacecraft in relation to the stars) failed and Kepler can no longer be aimed properly. The orbital observatory initially had four reaction wheels—one of which was a spare– however the spare wheel failed in July of 2012 and at least three wheels are required to operate the satellite. If NASA cannot somehow reactivate the flywheel, then the mission is over.
Likewise on November 2, COROT suffered from a computer failure which made it impossible to collect data from the satellite and its status remains uncertain. Most likely it is offline forever. So our ability to find huge numbers of exoplanets via space observatory has temporarily been halted.
Kepler was launched in 2009 for a four year mission, however the mission was recently extended until 2016 (since it took longer to collect and make sense of the data then initially planned). At last count Kepler had discovered 132 planets and was monitoring more than 2,700 further candidate planet. As of November 2011, COROT had found 24 new worlds and was screening around 600 additional candidates for confirmation. Additionally two years of Kepler data has been downloaded but not yet interpreted so post-mortem discoveries may lie ahead.
It is frustrating that the age of almost daily discovery of new worlds has come to a temporary end due to equipment failure, however a new generation of planet finding missions is already on the drawing board. To quote The Guardian:
The European Space Agency announced last year that it would launch the Characterising Exoplanets Satellite (Cheops) in 2017 to study bright stars with known planets orbiting them. Nasa’s successor to Kepler will be the Transiting Exoplanet Survey Satellite (Tess), which will conduct a survey of planets around more than two million stars over the course of two years.
RIP Kepler and COROT, you discovered so many planets and you will be missed, but your successors will be even greater.
Exciting news from the heavens! Today NASA has reported that the Kepler mission has discovered 3 new planets in the habitable zones of two distant stars. Of the thousands of worlds so far discovered, these three are most likely to be habitable. Best of all the planets are crazy!
Kepler is a NASA space telescope which was launched on March, 2009. It makes use of an incredibly sensitive photometer to simultaneously & incessantly monitor the brightness of over 150,000 nearby stars. The brightness of a star dims slightly whenever an exoplanet transits between it and Kepler. Thanks to Kepler’s inhuman vigilance and robotic ability to perceive nearly imperceptible light changes, we are now discovering thousands of new planets, although most of them are Jovian sized gas worlds.
The three worlds reported today lie in the habitable zone—the region around a star where water exists in a liquid form (as it does here on beautiful Earth). Two of the newly discovered habitable zone planets are in a five planet system orbiting a dwarf star just two-thirds the size of the sun which lies 1,200 light years from Earth. Here is a diagram of the Kepler 62 system.
Of these five worlds, two lie in the habitable zone, Kepler 62f and Kepler 62e. Kepler 62 F is most likely a rocky planet and is only 40 percent larger than Earth. It has an orbit which last 267 (Earth) days. So far it is the smallest exoplanet found in the habitable zone. The star it orbits is 7 billion years old (as opposed to the sun which is four and a half billion years old) so life would have had plenty of time to develop. The other habitable zone planet in the Kepler 62 system, Kepler 62e is probably about 60% larger than our planet. It is somewhat closer to the star and astrophysicists speculate it may be a water world of deep oceans.
The other new exoplanet Kepler-69c appears to orbit a star very similar to Earth’s sun. It orbits at the inward edge of the habitable zone (nearing where Venus is in our solar system) so it may be hot. The planet is estimated to be about 70% larger than Earth, and is also thought to be a water world with oceans thousands of kilometers deep. I am finding it impossible not to imagine those vast oceans filled with asbestos shelled sea-turtles the size of dump trucks, huge shoals of thermophile micro-squid, and burning-hot chartreuse uber-penguins, but if any life is actually on Kepler-69c, it is probably extremely different from Earth life.
Of course Kepler can only find these planets; it is unable to observe very much about them. In order to do that, humankind will need some sort of huge amazing super telescope. Speaking of which, tune in next week when I write about humankind’s plans for building a huge amazing super telescope in the Chilean Andes!
I am combining two important science discoveries from this week into one (small) post. This week astrophysicists working on the Keplar program discovered the three smallest known exoplanets (each of which is smaller than Earth) in orbit around a little red dwarf star. In a completely unrelated field (and scale) of science, biologists in Papua New Guinea discovered the world’s tiniest known vertebrates, two species of miniscule rain forest frogs named Paedophryne amauensis and Paedophryne swiftorum.
The exoplanets were discovered by a team led by scientists from Caltech who used data from NASA’s mission in conjunction with observations from the Palomar Observatory, (outside San Diego), and the W.M. Keck Observatory (on Mauna Kea in Hawaii). The three planets orbit tiny red dwarf star KOI-961 which has a volume only one-sixth that of our sun (making the star only about 70% bigger than the planet Jupiter). The planets are all very close to their star, and the most distant, takes less than two days to orbit around KOI-961. The three worlds have volumes of 0.78, 0.73 and 0.57 times the radius of Earth.
Red dwarf stars make up four out of five stars in the galaxy, but because they are so small and dim, the Keplar probe has only been assessing a relatively tiny group of red dwarf stars for the possibility of planets. The fact that studying a small sample of red dwarfs already revealed three terrestrial planets strongly suggests that such planets are commonly found around red dwarfs. John Johnson, of NASA’s Exoplanet Science Institute at the California Institute of Technology in Pasadena summarized the data by saying, “This is the tiniest solar system found so far…It’s actually more similar to Jupiter and its moons in scale than any other planetary system. The discovery is further proof of the diversity of planetary systems in our galaxy.”
The discovery of the tiny frogs was made by a team of zoologists in New Guinea led by Chris Austin, a herpetologist trained at LSU. The team was in the forest of New Guinea when they heard a faint metallic song coming from the leaf litter on the forest floor. Unable to see the animal producing the faint chorus of “tink” noises, the biologists grabbed up handfuls of leaf litter into a large transparent bag, and began carefully sorting it–expecting a singing insect to emerge. They were stunned when the miniscule adult frog hopped off a leaf. The fully grown creature only measured 7.7 millimeters (less than one-third of an inch).
Named Paedophryne amauensis the little amphibians are not just the smallest known frogs–they are also believed to be the smallest free-living vertebrates on Earth (supplanting a minute 8mm long translucent Indonesian carp for that title). The frogs do not undergo tadpole metamorphosis in water like other frogs, but are born hopping. They spend their entire lives in the leaf litter where they prey on miniscule arthropods and other invertebrates. A similar species Paedophryne swiftorum was also discovered by the team, although P. swiftorum frogs were nearly a millimeter larger.
In an interview, the team leader Chris Austin said, “We now believe that these creatures aren’t just biological oddities, but instead represent a previously undocumented ecological guild — they occupy a habitat niche that no other vertebrate does.”
As I write this, astronomers know of about 700 planets which lie beyond the solar system. Yet in just 16 months, NASA’s Kepler mission has discovered an additional 2,326 potential new planets. This figure is hitting the mainstream news today thanks to NASA’s announcement that the Kepler space observatory has confirmed the existence of Kepler-22b, a planet which exists within the so-called habitable zone of a yellow G-class star about 600 light years from here. Kepler-22b orbits its star every 290 Earth days and is reckoned to have an average temperature of about 22 degrees Celsius (approximately 72 degrees Fahrenheit). Although closer in size to Earth than most exoplanets, the new world still has a radius which is more than twice that of our planet(which means that Kepler-22b’s mass is immensely greater). Scientists have no idea what Kepler-22b is made of, but because of its high gravity, its atmosphere is likely to be a heavier, sludgier affair than that of Earth.
The discovery of new worlds is becoming progressively more common–which means that new planets are more difficult to write about (I can testify to this because I have been trying to think of novel and exciting things to say about this new exoplanet). The top google search result for Kepler-22b is currently a smug caricature of the foibles of earthlings. Within a few days the sparse prose of Wikipedia’s equally scanty entry will probably be the top search result—and that is likely the way that things will remain for a long time (or forever). We are beginning to compile a massive database of different worlds. As the numbers add up, the true stories will be within the statistical understanding of new planets–unless of course a habitable zone planet leaps out of the news with electromagnetic signatures characteristic of life and intelligence. That result becomes progressively likely as we begin to learn where to point our telescopes. Out of the thousands of planets the Kepler mission is finding, Kepler-22b is the first habitable zone world of dozens–or of hundreds.
[Alien clipart by Elizabeth Aragon at www.sweetclipart.com]
Today scientists announced the discovery of the exoplanet Gliese 581 g which lies 20.3 light years away from Earth in the planetary system of the red dwarf star Gliese 581 (a star with one third the mass of our sun). The planet has three times the mass of Earth and is almost certainly tidally locked to its star (in the same fashion that the moon always presents the same face to earth). It revolves much more closely around its dim little star than our planet does around our sun: the yearly orbit of Gliese 581 g is just 37 of our earth days. With four known planets, the star Gliese 581 had already featured the largest known planetary system outside of our own (before two more worlds were added to the system in today’s announcement). When exoplanet Gliese 581 d was discovered in 2007, it was regarded as the most earthlike exoplanet and scientists speculated about its potential for harboring life (though Gliese 581 d is now regarded as too cold to have liquid water). Oh, the discovery of Gliese 581 f was also announced today–but nobody cares since it is located far outside what scientists regard as the habitable zone.
The planet was discovered by the Lick-Carnegie Exoplanet Survey headed up by Dr. Steven Vogt. The team has taken to calling it “Zarmina” after Steven Vogt’s wife, which I think this is a very beautiful name for a world. I’m also moved by the fact that Dr. Vogt’s first impulse would be to name the world after his spouse (and I also like the fact that she has a Pashtun name). Unfortunately we’ll probably get stuck with something less euphonious—probably “Gliese 581 g”. I guess our astronomical naming conventions confer mixed blessings—I’m still happy we don’t call Uranus “Georgium Sidus” like Sir William Herschel desired.
Speaking of Herschel and planetary discovery, I was pleased to see that Vogt continued Sir William’s glorious tradition of exuberant speculation about extraterrestrial life. At this morning’s press conference, Vogt boldly asserted that “my own personal feeling is that the chances of life on this planet are 100 percent.” He then spoke about the possibilities of polar bear like life-forms living on the planet’s cold night side, thermophilic life-forms on the hot half, and temperate life forms living on the twilight ring dividing the two extremes.
As with most science news, the planet’s discovery hasn’t produced a huge splash in the media (the discovery of the most earthlike planet so far known was greatly overshadowed by Tony Curtis’ death). The few short mainstream news article to mention this discovery were striking to me for their comments sections. Although many people leaving comments were filled with wonder and curiosity, a distressing number seemed very ignorant of basic scientific principles (or basic principles of anything). A shocking number of commenters wanted to send all Republicans to Gliese 581g (an equal number wished to send all Democrats instead). What happened in or national discourse that a citizen’s first reaction to hearing about a new planet is to banish his political foes there? When did the United States become Renaissance Florence? Other people demanded that we not exploit the newly discovered planet’s resources but instead concentrate on solving our problems here on earth (20.3 light years might seem like a tiny number but it converts to 1.92048727 × 1017 meters). We probably have better sources of bauxite and blood diamonds! In a similar vein, quite a few folks demanded that we stop studying the heavens altogether and provide them with cushy jobs, new sofas, and tv dinners. In short, the comments made me sad and frustrated.
Corot and Kepler, the two big missions for spotting earthlike worlds (from the French and NASA respectively), are only just beginning to yield discoveries, so I expect we will be hearing about a lot of earth-like worlds. Let’s hope humankind grows technologically, socially, and politically as the new planets are tabulated!
[Also, rest in Peace Tony Curtis, I loved you in “The Great Race” when I was 6.]