2006年VOA标准英语-Nobel Prize Science Winners Made Important Cont(在线收听) |
By Deborah Block Americans received four of the six Nobel Prizes. Recently, VOA's Deborah Block spoke with several of the winners in science about their breakthroughs -- ranging from an exciting new discovery in genetics, to a new look at the start of the universe. People have long wondered when the universe began -- how the galaxies started, where the stars came from. Most scientists agree with what is known as the "Big Bang" Theory -- almost 14 billion years ago the portion of the universe we can see today was only a few millimeters across. It has since expanded from a hot, dense state into the vast and much cooler cosmos. Smoot and Mather based their findings on measurements of what's called blackbody radiation -- a remnant of the earliest radiation in the universe. Instruments onboard a satellite called Cobe measured that radiation. According to the Big Bang theory, as the intense heat from the blackbody radiation gradually cooled, the universe expanded. Mather is with the U.S. Space Agency's Goddard Space Flight Center in the state of Maryland. He says measuring the radiation's spectrum of color and brightness was key. “And so the spectrum measurement basically confirmed that the Big Bang Theory is basically the best theory we have for the origin of the universe -- that the whole universe that we're in now came from a volume no bigger than a golf ball about 13.7 billion years ago. And with the Cobe satellite we saw the hot and cold spots in this radiation that are density fluctuations left over from the Big Bang itself. And we believe that those particular regions are the ones that made galaxies and clusters of galaxies form so that we could exist." Known as RNA interference, it can be found in plants, animals and humans. Fire is a genetics professor at Stanford University. "There was evidence of this very effective force in biology, essentially, that could shut genes down and the question is what triggered it. And we were looking for clues about that and what we actually found was a very, very specific unique structure." By controlling genetic information, RNA interference can provide a defense against viruses and control genes, which cause diseases like cancer. Smoot says he is now on a new scientific quest -- to find out what happened before the Big Bang. |
原文地址:http://www.tingroom.com/voastandard/2006/12/35965.html |