National Science Foundation
Lake Vostok is located 2.48 miles beneath the East Antarctic Ice Sheet. Pictures is Lake Vostok station.
Nov. 8, 2011 --
Despite the occasional report of an extraterrestrial sighting, be it through a microscope revealing curious shapes in a meteorite or a photo of wispy lights taken at the blurry end of a camera lens, aliens have yet to make contact with humans. Even the White House yesterday put out a statement declaring that the federal government "has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race." Humans may not yet have encountered life outside of our planet, but many scientists see it as an inevitability. In 1960, astronomer Frank Drake came up with the now eponymous equation which provided an estimate of the number of civilizations in our galaxy. Although scientists continue to debate the application of his formula as well as alternatives, Drake's own solution to the equation is 10,000 civilizations, suggesting intelligent, technologically advanced life outside our planet is common. How these different civilizations, including our own, find each other is an important question for anyone here on Earth looking for extraterrestrials. Explore how aliens might stumble upon our planet -- and how we might actually spot them first.
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Before we can began to search the skies, we have to start by narrowing down our options. Sticking within our own galaxy is a good start, since we're more likely to spot a neighbor closer to us than one further away. Astronomers may also elect to focus their attention on stars closer to the center of the Milky Way, where 90 percent of its stars are clustered. Furthermore, the stars here are a billion times older than the sun, giving life more time to develop biologically and technologically. Many stars are unsuitable for nurturing life, and even stars that do have the appropriate "spectral type" may host exoplanets inhospitable to life due to their location relative to their parent star, size or composition. These criteria would not only help us find aliens, but also help them find us. After all, Earth would stand out as a hospitable planet, according to a paper published in 2007 in Astrophysical Journal.
If aliens are looking for us, they're scanning the same, vast, dark and mostly empty expanse of space that we are. It's a good thing then that we're leaving the lights on to make it easier to find us. According to Abraham Loeb, of Harvard University and Edwin Turner, from Princeton University, by scanning the skies for artificial illumination as opposed to naturally occurring light sources, both human and extraterrestrial astronomers might be able to find signs of life. Existing telescopes would be able to see a city the size of Tokyo as far as the edges of our solar system.
BLOG: CITY LIGHTS COULD REVEAL ET
For more than 25 years, the SETI Institute has been scouring the skies for signs of alien life. However, long before the institute was established, scientists have tried to catch a communication signal from another world. Scientists looking for alien signals use a combination of optical and radio telescopes, such as the one seen here. Dropping in on a signal without knowing the source of the communication is the tricky part, however, and researchers narrow down their search by targeting specific kinds of stars. With their citizen science program, SETI@home, the institute has enlisted three million additional observers analyzing data for traces of an alien signal.
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Have aliens already stopped by for a visit, even though we weren't at the door to meet them? If they have, shouldn't they have left something behind? An artificial object of alien origin could be lurking in our solar system without our knowledge. As Discovery News' Ray Villard explains: "In a paper published in the 1960s, Carl Sagan, using the Drake Equation, statistically estimated that Earth might be visited every few tens of thousands of years by an extraterrestrial civilization." Further out beyond our solar system, aliens may have left what essentially amount to interstellar billboards large enough to be seen by, say, a planet-hunting telescope like Kepler. These last two scenarios, of course, envision an extremely technologically advanced civilization well beyond the engineering capabilities of humankind. At the same time, humans have sent spacecraft beyond the solar system, including Pioneer 10 and 11 as well as Voyager 1 and 2. All of these spacecraft are equipped with what are essentially calling cards for the human race -- small plaques in the case of the Pioneer spacecraft and golden records for the Voyager spacecraft (seen here).
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Humans may rely primarily on fossil fuels as their primary means of energy, but that doesn't mean extraterrestrials in a far off civilization have the same power source. Solar power could be one option, though not quite with the same black panels we use on Earth. A super civilization could even tap into a black hole to meet its energy needs. If aliens are tapping to these cosmic bodies, that should make them all the more detectable from Earth. How would we know whether an alien race was relying on a black hole as a source of energy? As Discovery News' Ray Villard explains: "Tell-tale evidence would come from measurements that showed the black hole weighed less than 3.5 solar masses. That's the minimum mass for crushing matter into a black hole via a supernova core-collapse."
In one of the most unusual -- and highly unlikely -- first-contact scenarios, aliens would be able to recognize us by the level of greenhouse gas emissions we pump into our atmosphere. Not only that, according to a hypothesis put forward by researchers affiliated with NASA and Pennsylvania State University (though not directly tied with either institution), but aliens may use that as cause to wipe out the human race. In this bizarre set of circumstance, aliens view human advancement as a destructive force spiraling out of control. To avoid the threat of a future adversary, extraterrestrials clear out the competition.
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— Buried Lake Vostok may hold unknown life forms.
— Learning how life spreads and where to find it may help in the search for life beyond Earth.
— Water samples from the lake will be retrieved next year.
When a Russian team broke through 12,365 feet of solid Antarctic ice last week to reach an ancient buried freshwater lake, scientists eager to fill some gaps in Earth's history were overjoyed. But they weren't the only ones.
Seeing parallels between Antarctica's subterranean Lake Vostok and suspected oceans beneath the ice-crusted moons of Jupiter and Saturn, scientists searching for life beyond Earth are eagerly following the Russian project.
They don't expect water samples from Lake Vostok will hold alien life, though any life it contains may have taken a slightly different evolutionary path than what appears on the planet today. That's because Lake Vostok, the deepest and most isolated of Antarctica's subglacial lakes, has been cut off from the atmosphere for at least 14 million years.
The lakes, which were discovered via satellite imagery in the late 1990s, owe their existence to the thick Antarctic ice, which acts like a blanket to trap heat coming from inside Earth, keeping water liquid.
"If they find evidence of life there — and I do think Lake Vostok has life in it — it's going to be Earth-like," astrobiologist Dale Andersen, with the SETI Institute's Carl Sagan Center for the Study of Life in the Universe, told Discovery News.
"It's going to be the same kind of life you find everywhere else. It may be that life has evolved differently, but it's still Earth-like, still based on the same DNA structure," Andersen said.
"The real value is that it helps us learn how to explore these kinds of environments better. It opens up your imagination for how to explore these kinds of environments, whether it's on Earth or Europa," he said.
Scientists suspect Lake Vostok's water is about 1 million years old and is supersaturated with oxygen and other gases, a difficult place for life to exist. Some life that might be there are bacteria and single-celled microorganisms called archea.
It would be surprising if Lake Vostok had no life, NASA astrobiologist Chris McKay told Discovery News.
"The ice above the lake is known to contain low levels of viable but dormant organisms frozen into the ice. As this ice melts into Lake Vostok, it will carry these microorganisms so Lake Vostok is not likely to be sterile," he said.
"Sterile is not the same as habitable," he added. "It may be that the environment in the lake does not provide an energy source or nutrients for life. Thus, there may be life there carried in with the melting ice, but there would not be an ecology."
Lake Vostok may offer lessons on how life spreads and how to find habitable environments. The project also should help scientists and engineers designing equipment to look for life beyond Earth and processes to make sure anything found is not the result of contamination.
Whatever secrets Lake Vostok holds are safe for at least another year. Russia won't be able to retrieve its water sample until the next Antarctic summer. By that time, teams of British and American scientists may have had time to retrieve and analyze samples from two other shallower sub-glacial lakes.