The Search for Extraterrestrial Life

NASA's Kepler mission successfully launched into space from Cape Canaveral aboard a Delta II rocket on Friday, March 6, 2009. According to NASA, Kepler is designed to find the first Earth-size planets with water – essential for life as we know it to develop.

The first planets that Kepler will explore are expected to be the "hot Jupiters" -- gas giants that circle close and fast around their stars. NASA's Hubble and Spitzer space telescopes will be able to follow up with these planets and learn more about their atmospheres. Neptune-size planets will most likely be found next, followed by rocky ones as small as Earth. The true Earth analogs -- Earth-sized planets orbiting stars like our sun at distances where surface water, and possibly life, could exist -- would take at least three years to discover and confirm. Ground-based telescopes also will contribute to the mission by verifying some of the finds.

NASA says that in the end, Kepler will give us our first look at the frequency of Earth-size planets in our Milky Way galaxy, as well as the frequency of Earth-size planets that could theoretically be habitable. According to NASA, "Even if we find no planets like Earth, that by itself would be profound. It would indicate that we are probably alone in the galaxy."

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In December 2000, the research vessel Atlantis, a deep submersible, found an entirely new type of hydrothermal vent field, where active chimneys were emitting water heated to a relatively cool 100°F (40°C) to 170°F (80°C). They called the field "Lost City." The heat resulted from a chemical reaction between water and a subcrustal rock called peridotite. When the alkaline solution emerged, calcium carbonate crystallized, building shapes like stalagmites.

Until Lost City was found, most known deep-sea vents sprang from young, volcanically active regions such as mid-ocean ridges, where sulfide chimneys expel water as hot as 760°F (400°C). Yet Lost City's formations lie nine miles from the Mid-Atlantic Ridge on 1.5-million-year-old rock in an alkaline environment that may be similar to that of early Earth.

More fascinating still, the recent study of deep-sea vents reveals that surrounding life is based on chemosynthesis, the conversion of chemical energy into biomass, rather than photosynthesis, which converts light into biomass. Such a discovery broadens the search for life in the universe.

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The most enduring and compelling question for man is, "Are we alone in the universe?" By that, we mean are there others out there like us? That's why the term extraterrestrial life is usually qualified by "intelligent life as we know it." That's a problem, because intelligent extraterrestrial life may be nothing like what we know.

As it happens, there is no universally agreed upon definition of intelligence. We tend to think of human intelligence as involving higher order reasoning -- a cognitive ability that lets us learn from, adapt to, and deal effectively with our environment. We are predisposed, one might say, prejudiced, to see this ability emanating from an organ -- the brain -- in an individual body. Seth Shostak , a senior astronomer at the SETI Institute, when asked what extraterrestrials might look like said, “They'll be bigger than a breadbox and probably smaller than an elephant, would be my guess.” Think ET.

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Intelligent life need not take the form we envision, however. Extraterrestrial intelligence may exist in a distributed form. It's interesting to note, for example, that SETI itself is using a form of distributed intelligence to explore the cosmos for extraterrestrial intelligence. SETI@home is a scientific experiment that uses Internet-connected computers in the search. Anyone with a computer can participate by running a free program that downloads and analyzes radio telescope data.

We have life here on earth that defies our preconceived notions of what a living organism should look like. Take the sea jelly, or more commonly, the jellyfish, for example. It has no specialized digestive, respiratory, or circulatory systems. Its mouth is also its anus. It has no eyes. It has no brain (except for the Box Jellyfish, which has four separate brains) and no central nervous system, but rather a loose network of nerves, located in the epidermis, which is called a "nerve net." A jellyfish detects various stimuli, including the touch of other animals via this nerve net, which then transmits impulses both throughout the nerve net and around a circular nerve ring to other nerve cells. Jellyfish seem to sense when their species is in danger and reproduce exponentially. One species of jelly, the Turritopsis nutricula, is effectively immortal. It can revert completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary stage. It does this through the cell development process of transdifferentiation. Theoretically, this cycle can repeat indefinitely, rendering the T. nutricula biologically immortal.

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In a future post I will discuss the idea of a life form connected not by tissue, but by a cosmic distributed intelligence that incorporates components on earth.