Gambling on Extraterrestrial Life

The latest discovery of ice and organic molecules "of a complex nature" on the surface of asteroid 24 Themis made public in Nature magazine doesn't even seem to raise an eyebrow anymore. Nor did the Mars Phoenix Lander 's amazing time-lapse images of microorganism-like objects moving on the Martian surface (see the link). We seem to have become rather blasé when it comes to the question of whether extraterrestrial life exists or not. By all indications, it's right here right now in our own solar system and it's almost a foredrawn conclusion that we will soon have the definitive proof to back it up. But where is the real evidence now?

There is none. Not yet anyway. And no, there is none despite the fact that the life forms we are searching for here are not the ones of the popular alien or UFO variety. Stephen Hawking's recent warnings about potential alien invasions ("If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans") should not give us cause to worry. The extraterrestrial creatures we are coming ever closer to making contact with stem from the realm of astrobiology.

There is in fact a growing body of evidence that strongly suggests our solar system is very abundant in the elements we know to be essential for the development of carbon-based life, water being among them. We certainly don't know why or how, but we do know that life "happens." And it happens practically everywhere - here on Planet Earth. We may not know how amino acids become cells with DNA which then become life, there is a huge unanswered gap between these building blocks of life and the life forms themselves, but we do know that at some point, this strange mix of chemicals cames alive. It only stands to reason then that if the primoridal soup is the same or similar elsewhere in the solar system as it is here, then life, ever adaptable as it is, will develop there too.

Mars, of course, still appears to be the best bet when it comes to finding alien life in our own solar system. The red planet is not only our next-door neighbor, it also has a similar size to that of the Earth. It's temperature range is relatively similar as well. The chances of finding water beneath the planet's surface are very high as Mars' poles are covered with ice. Looking for microbes beneath the surface, the Viking probe's Labeled Release biological experiment even returned a positive result, showing increased CO2 production by Martian soil exposed to water and nutrients. Another Viking test also helped back these finding up. But unfortunately, as noted by the British astronomer David Darling in his book "We Are Not Alone", although these two chemical reaction experiments conducted by Viking's microbiology lab pointed to the existence of organisims in the red planet's soil, a third experiment conducted by the lab failed to do so and, cautious scientiests being what they are, that was enough to question the validity of the first two results. Ironically enough, the same instrument that failed to find life on Mars also failed to find life on another planet when tested again later - here on Planet Earth.

Other instances of possible alien life evidence in our solar system abound. In 2004, on Mars again, three independent groups of scientists using telescopes and ESA's Mars Express space probe found evidence indicating methane in the Martian atmosphere. Methane is usually destroyed by sunlight, and this makes scientists wonder. Here on Earth, life constantly replenishes the atmosphere with methane and it could just be that the same process is taking place on Mars as well.

Jupiter and Saturn have moons with underground oceans, methene and hydro-carbon lakes, all relatively habitable environments that offer the basic conditions needed for the formation of life. Saturn's moon Titan even has an atmosphere. Titan's atmosphere is actually quite thick and appears to be rich in chemical compounds that could mark the presence of living organisms. It's air is filled with methane too.

Jupiter's moon Europa has a red tinge caused by sulphur traces which give off a strange infrared signal that some scientists attribute to frozen bits of bacteria located there. This is similar to the infrared spectra of some bacteria on Earth which thrive in extreme conditions. Sulphur signatures like these are like the bacteria waste-products which have been locked into the ice surfaces of Antarctic lakes on Earth. Although Europa's surface appears to be frozen, ample evidence points to the possibility of an ocean of liquid water beneath that frozen surface. And volcanism here might provide enough life-supporting heat to help form life.

Jupiter's moon Io supports its own atmosphere and seems to be filled with a complex mix of chemicals that might be promising for life. The volcanic activity here is more pronounced and also makes it warmer than other moon candidates for life.

Another very interesting environment for life could be on Enceladus, Saturn's sixth-largest moon. It has a much milder temperature than the other worlds mentioned and being that it's surface is almost completely covered with water ice, there is a very good chance that there is liquid water beneath. When the Cassini orbiter examaned Enceladus in 2005, it even determined the presence of oxygen, hydrogen, nitrogen and carbon. And in addition to that, scientists believe that Enceladus actually has a molton core which might provide enough heat to give these organic molecules the proper conditions to develop life.

So when will we have the conclusive evidence for extraterrestrial life in our solar system? Within the next five to ten years, most likely. Numerous laboratory probes will either continue or soon be broadcasting their findings back home: NASA's Mars Exploration Rovers, the Cassini orbiter, a Europa/Jupiter system orbiter, NASA's Mars Science Laboratory (MSL), ESA's ExoMars mission and the Mars Express, the EPOXI and NExT comet exploration missions and the Dawn asteroid exploration mission and on and on and on.

That our solar system offers the basic elements necessary for the development of life is no secret anymore. We are rapidly reaching the the point where the speculation about whether extraterrestrial life exists or not will become irrelevant. Nature's compulsion to create life, and with it intelligence, is an unstopable force. Wherever it is possible for life to come about, it will, and we are now entering the age in which human contact with extraterristrial life forms will begin.

Or as David Darling puts it: "For many people, the main question about extraterrestrial life is whether or not it exists. To much of the scientific community, however, that question has already been answered: It does."

Sources:
Author - David Darling
Book - We Are Not Alone: Why We Have Already Found Extraterrestrial Life http://www.daviddarling.info/works/We_Are_Not_Alone.html
Site Title - The Worlds of David Darling
http://www.daviddarling.info/

Author - shineinnovations, a narration by Ron Bennett
Page Title - Things that moved on the Mars Phoenix Lander caught by its Microscopic Imager
http://www.youtube.com/watch?v=zhfSjJeQf58
Site Title - shinneinnovations (YouTube)
http://www.youtube.com/user/shineinnovations

Author - Clara Moskowitz
Page Title - Top 5 Bets for Extraterrestrial Life in the Solar System, Wired Magazine
http://www.wired.com/wiredscience/2009/01/et-life/
Site Title - Wired
http://www.wired.com/

Author - Ki Mae Heussner
Page Title - Stephen Hawking: Alien Contact Could Be Risky
http://abcnews.go.com/Technology/Space/stephen-hawking-alien-contact-risky/story?id=10478157
Site Title - ABC News / Technology
http://abcnews.go.com/Technology

Author - Henry H. Hsieh
Page Title - Ice on asteroid 24 Themis
http://www.nature.com/nature/journal/v464/n7293/edsumm/e100429-05.html
Site Title - Nature
http://www.nature.com/nature/index.html

Author - Wikipedia
Page Title - Extraterrestrial Life
http://en.wikipedia.org/wiki/Extraterrestrial_life
Site Title - Wikipedia
http://de.wikipedia.org/