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The Webfooted Astronomer - February 2000
Minutes: Good Food, Astrobiology and Prizes
by Leslie Irizarry
THE annual SAS awards banquet was held at the Yankee Grill in Ballard on January 29. After a delicious dinner, Jerry West introduced the speaker, Woody Sullivan. Woody is a professor of astronomy at the University of Washington, who discussed the new doctorate study in astrobiology. In history, there have been individuals who did not consider the Earth as the only place in the universe where life existed. People have long been speculating about the possibility of extraterrestrial life. An example is in a book called the Conversations on Plurality of Worlds by Fontanelle. The premise is that God would not have made other stars if there were not other planets around them.
Astrobiology embraces the big scale of astronomy and the small scale of biology. It asks the questions: Could life happen elsewhere? Could life happen "elsewhen"? Could life happen "elsehow"? (Will it be like ours, based on carbon, dependent on water, with same genetic code?) What has triggered interest in astrobiology are four phenomena:
Extremophiles are microbial organisms that live in extreme conditions. New discoveries demonstrate that microbes (and life) are much hardier than once thought. Planets are now known to be going around other stars. Though most astronomers believed this was the case, it has now been demonstrated to be fact.
Mars: the evidence is strong that Mars was, in its first several hundred million years, very warm, wet, and earthlike. The Martian meteorite that landed in Australia triggered interest in this, although the conclusion drawn initially that this meteorite contained microbial life appears to have been wrong. However, theoretically, there could be fossils delivered from one planet to another. Europa probably has a liquid water ocean beneath its icy crust. If you have a few billion years, heat, and water, maybe life would develop.
The moon and Earth went through a period of bombardment, which stopped after 3.8 billion years. Afterwards, single-celled organisms came into being and existed for 3 billion years. Astrobiologists wonder if this stasis is characteristic of another biology elsewhere. After 3 billion years, there was a remarkable growth in the number of species. This period represents the last 10% of the planet's history. Thus, you may be much more likely to find microbial life in the search for extraterrestrial life.
Thermopiles are the oldest organisms. Maybe the earliest organisms didn't start with a nice tepid pond but in extreme conditions. After all, Earth was hotter during the period after the bombardment ceased. In Eastern Washington one mile beneath basalt, there are bacteria that live off the hydrogen given off by basalt. The water has been there for as long as 100,000 to l million years. These bacteria have their own ecological niche. When you consider Mars, you may think of a lifeless planet. But perhaps there's life under the surface—1 meter or 1 kilometer. "It's a very hard life under those rocks."
There are stars that have other planets. Amateur astronomers can see the stars 47 Ursa Majoris and 51 Pegasi. A Jupiter-like planet is circling around 51 Pegasi. These planets are not Earth-like planets, but are rather more like Jupiter. However, if a planet is like Jupiter, it may have its own satellites around it, with possibility for life there. About 5% of solar-like stars have Jupiter-like planets.
The findings of the Jupiter-like planets orbiting close to its star doesn't agree with the formerly commonly-held model which states that smaller rocky planets are located near the sun, and gas giants are located further out. Clouds above Mars have a blue tint probably because of water. Below the surface of Mars is probably permafrost. There is evidence of flowing water a long time ago. The northern hemisphere is lower than the southern hemisphere, indicating there may have been oceans in the northern hemisphere. Carbon dioxide may be locked up in the rocks. On Earth, carbon dioxide cycles through rocks.
The recently discovered meteorite in which scientists claimed that they found evidence of fossils is problematic mainly because of the size of the fossils: they are one-tenth of a micron. This is not large enough for ribosomes. The place to find meteorites is in Antarctica. 10,000 have been found in the last decade. They stand out against the ice and snow, and glaciers deliver them like a conveyor belt. When a large meteor hit Mars, it spewed out matter. Chunks of this matter came to Earth. The age of the aforementioned rock is 4.5 billion years and it is certainly part of Mars—this is known because of analysis of pockets of gas that matched beautifully with the gas analyzed by the Viking mission to Mars.
Europa is the second moon from Jupiter and has an icy surface with cracks on it. There are no craters, which suggests that the surface is young. Ice is likely "boiling" up and down over tens of thousands of years. One can see chunks of ice breaking off from each other. It is thought that Europa has a small rocky metal core, a rocky interior, and liquid water with an ice covering. This liquid water is not frozen because of the tides brought about by Europa's interaction with Jupiter. The ice may be between 1 km to 100 km deep. A tiny electric field was detected—this is possible only if the liquid water is brine.
In the 16th century Copernicus transformed the world view from a geocentric one to a heliocentric one. In the 20th century Shapley transformed the view from a heliocentric to galactic. Hubble changed us from a preferred location to NO preferred location and Darwin led us away from anthropocentricity. But, we may be biocentric. Can it really be that our life is unique?
Stars of the SAS Awards
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