问答题 The discovery last week of possible evidence of life on Mars has electrified debate over whether the universe is a barren void or a nursery pregnant with life.
Scientists who have come stunningly close to repeating genesis, or the origin of life, in a test tube, say the building blocks for life exist everywhere. The challenge is putting them together. (46) "The origin of life is a relatively easy concept and there's a wide variety of conditions under which it will take place," said late Stanley Miller, a professor at the University of California and a pioneer in the field. "Perhaps the remarkable thing is that even though Mars is not a favorable environment, the origin of life took place. "
Astronomers have found that the same gases present in our solar system are present throughout the universe.
(47)Efforts to make microscopic life from these basic elements on Earth suggests the chance of life arising under similar circumstances is the same everywhere, say chemists, biologists and other experts.
"It seems fairly likely that life similar to ours, if there is water available '" would evolve in other environments in our galaxy or our universe," said James Ferris, a leading researcher and editor of the journal "Origins of Life and Evolution of the Biosphere."
Underlying much of the research is the question.. Was the development of life on Earth unique, or did the universe's chemical elements naturally evolve into life? (48) The answer appears to be that at least the chemical reactions that set the stage for early life would be similar everywhere, but resultant living organisms would differ because of the genetic mutations in evolution.
"If you've got the same starting materials and the same conditions, you're going to get the a me compounds, that's for sure," Miller said. "The real question is whether or not there are chance elements in the formation of life."
(49) In a 1953 experiment, Miller mixed basic gases approximating the Earth's early atmosphere with an electric charge inside a glass chamber and produced amino acids, a primitive building block of life. He then suggested that life was a natural evolution. It seemed that science was on the verge of conjuring up creations in the laboratory, but the next 43 years were to present unexpected challenges.
(50) "Making the amino acids made it seem like the rest of the steps would be very easy; it's turned out to be more difficult than I thought it would be," Miller said in an interview.