No Alien Signals Detected From Kepler's New Exoplanet
After pointing the Allen Telescope Array at a newly-found exoplanet discovered by NASA's Kepler space telescope, SETI reports there is no transmitting alien civilization. But the search continues...
SETI has pointed a powerful radio telescope array at the Kepler Space Telescope's most recent exoplanetary discovery in the hope of detecting an artificially-generated radio signal. Alas, the world is not transmitting, and probably isn't home to an extraterrestrial intelligence.
SETI, which stands for the Search for Extraterrestrial Intelligence, utilized the Allen Telescope Array (ATA), located in at Hat Creek Radio Observatory, 290 miles northeast of San Francisco, Calif., to study HIP 116454b, an exoplanet 180 light-years away in the constellation Pisces. The exoplanet, that measures 2.5 times the diameter of Earth (and is therefore defined as a ‘super-Earth'), was the first discovery made by Kepler in its rebooted "K2″ mission.
During its primary mission, the Kepler suffered the breakdown of its second reaction wheel in May 2013. The loss of stability forced Kepler into an early retirement. Fortunately, NASA engineers were able to think up an ingenious new mission profile that requires only two of the four reaction wheels to be operational. And in December, K2′s first exoplanet discovery was announced: HIP 116454b.
HIP 116454b isn't, however, what we would consider to be ‘habitable' in any way. The super-Earth has a rapid 9-day orbit around its host star and is therefore expected to be a roasted world, probably tidally locked (i.e. with one hemisphere of the exoplanet constantly facing its star).
Why would SETI bother aiming the ATA at this unlikely target, searching for radio signals from a hypothetical alien civilization?
"...as centuries of experience have shown, observation sometimes trumps expectation, and that is why new exoplanets - whether they seem promising for life or not - are routinely observed by the SETI Institute with the Allen Telescope Array," writes SETI Institute Senior Astronomer and Director Seth Shostak.
In other words, just because we deem a planet too harsh for "life as we know it" to evolve, science has this wonderful habit for turning up results we didn't expect - so why not listen in on HIP 116454b?
Historically, SETI has listened focused distant stars in the hope of detecting narrow-band radio signals from technologically-advanced extraterrestrials. The logic is that humanity is constantly leaking radio signals into space, and we consider ourselves to be at least technologically proficient, so if we can detect similar signals from another star system, perhaps there's another civilization out there at a similar state of technological can-do as us.
But before the age of exoplanetary discoveries, SETI was uncertain whether the stars they were eavesdropping in on even hosted planets. But now, especially since the launch of Kepler in 2009, there are an abundance of stellar targets that are known to host exoplanets - many of which orbit in the habitable zones of their stars. Therefore, following up on these Kepler discoveries with the ATA has ushered in a new era of "directed SETI."
So far, the ATA has been looking for signals in the 1000-2250 MHz range emanating from HIP 116454b and Shostak reports that higher frequencies will also be analyzed. It seems that directed SETI will leave no exoplanetary stone unturned in its epic and sustained mission to seek out intelligent extraterrestrial life in our galaxy.
Artist's concept of the first planet discovered by NASA's Kepler spacecraft during its K2 mission, a "super Earth" called HIP 116454b.
Cowboys & Aliens are Coming!
July 29, 2011 --
If aliens are going out of their way to kick up dust in the Wild West, as they do in the upcoming movie "Cowboys & Aliens," they must be coming from somewhere. Life could take root on a moon or a meteorite. But to nurture the kind of life that could destroy our saloons and harass our livestock, a planet might be the most suitable. So far, Kepler, a NASA orbiting telescope that searches for planets beyond our solar system, has detected over 1,200 exoplanets. Surely there must be a few candidates among this group that could meet some of the most basic requirements to host life? Explore some far-out worlds that could support aliens, be they cattle-rustling characters or a more peaceful people.
First, let's lay out some basic criteria. Kepler hasn't identified many rocky worlds and a solid surface is essential for life to take root. Size matters: The mass of the planet helps astrophysicists infer what it's made of. Some planets are Earth-sized. Others are several times the size of our planet. And then there are gas giants, which can range from "Neptune sized" to "super-Jupiters." Orbit: To support life, a planet must be in a stable orbit around its star -- no planets with wonky orbits that will eventually dump them into their star for a fiery death. Goldilocks Zone: This is a region not too hot or too cold that gives the planet enough distance from its parent star to have liquid water, key for life. Loner Stars: Single stars make better parents. In 2010, a pair of closely orbiting binary stars was spotted surrounded by what could be the debris of former planets. Unknowns: Some factors for life can't be confirmed one way or the other from the data available about extrasolar planets. These include: water, chemical compounds such as ammonia; a nitrogen-rich atmosphere; a magnetic field to repel solar and cosmic radiation; and more. BUT, some planets do have a head-start, beginning with Gliese 581D.
Located a mere 20 light-years away, practically our backyard in cosmic terms, Gliese 581d is situated on the "outer fringes" of the Goldilocks zone, orbiting a red dwarf star. The planet may be warm enough and wet enough to support life in much the same manner as Earth. It might also contain a thick carbon atmosphere. If we ever need a new Earth and have the means to get there, Gliese 581d may be our best bet for now.
When it was first detected and reported last year in Astrophysical Journal, Gliese 581g appeared to be the perfect candidate for a true "Earth-like" planet. Located in the same star system as Gliese 581d (and detected earlier), Gliese 581g seemed to be the right size and located within a habitable zone away from its parent star. Gliese 581g was said to have three times the mass of Earth, making it possible for the planet to hold an atmosphere. However, since its discovery, follow-up studies have alleged that Gliese 581g might have been a false alarm. In other words, the planet might not exist at all.
Dubbed a "waterworld" and located a mere 42 light-years from Earth, GJ 1214b orbits near a red dwarf star about one-fifth the size of our sun. What makes this planet unique is that it appears to be primarily composed of water, although GJ 1214b is 6.5 times the mass of Earth and 2.7 times wider, which classifies it as a "super-Earth." This planet also has a steamy atmosphere composed of thick, dense clouds of hydrogen, which, although it might not the case with this planet, could incubate life.
Situated 150 light-years from Earth, HD 209458b is a planet that holds traces of water vapor in its atmosphere, and also contains basic organic compounds that, on Earth, foster the development of life. But there are two factors working against HD 209458b as a suitable habitat. The planet is very hot due to its close proximity to its parents star, and it's a gas giant, so no solid surfaces.
If Kepler-10b were located further from its parent star, it might have had a chance of hosting life. Kepler-10b was the first "iron-clad proof of a rocky planet beyond our solar system" back in 2001. It was even dubbed the "missing link" of extrasolar planetary research. When it comes to the search for life, though, Kepler 10-b is missing a lot of other ingredients -- just minor things like water or an atmosphere.
When venturing to a new star system to explore the possibility of extraterrestrial life, trying a star that has already shown itself to nurture planets -- even if they're not the kind you're looking for -- could be a promising strategy. Project Icarus, an ambitious five-year study into launching an unmanned spacecraft to an interstellar destination, has identified two stars located within 15 light-years that might fit the bill: "epsilon Eridani, a single K star 10.5 light-years away, and the red dwarf GJ 674, 14.8 light-years away." Indirect evidence has also shown that epsilon Eridani may already hold smaller worlds scientists simply haven't detected yet. Also, red dwarf star systems generally may be a safe haven for life.
Are We Alone?
Taking into account the number of exoplanets that have been detected, as well as the vastly greater number that are estimated to be out there, some astrophysicists are convinced that extraterrestrial life is inevitable. After all, the Milky Way may be loaded with as many as 50 billion alien worlds. Some even think we'll find alien life by 2020. Others, however, say it may not exist at all. Recently, astrophysicists David Spiegel of Princeton University and Edwin Turner from the University of Tokyo suggested we might be alone in the universe, based on their interpretation of the Drake equation, a formula meant to determine loosely the probability of the existence of life beyond Earth. According to their analysis, just because life on Earth took shape early, endured and prospered doesn't mean the same process would naturally and inevitably occur elsewhere in the universe. Discovering life elsewhere, however, would be the only means of settling this debate. Unless the aliens find us first, of course.