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Past Shows
October 30, 2004
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Black Holes Tell No Tales
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The spiraling disc of gas gets hotter and hotter as it nears the black hole. On the point of falling into the black hole, the gas glows X-ray hot. Courtesy, NASA/GSFC
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Black holes are some of the strangest things in the universe. They’re massive gravity sinks: in theory nothing, not even light can escape from a black hole. At least, that’s the common belief.
But about thirty years ago, Dr. Stephen Hawking introduced an idea that threw a wrench into our thoughts about black holes. He said that, over time, black holes will evaporate. But if a black hole evaporates, what happens to all the things that went into the black hole in the first place? According to Dr. Hawking at that time, they disappear from existence.
Then this summer, Dr. Hawking reversed his position. Now he believes the information that makes up everything that goes into a black hole somehow emerges from the hole before it evaporates. Although he’s sketchy on the details.
Dr. Robert Wald is chair of the department of physics at the University of Chicago. He’s not convinced by Dr. Hawking’s change in position. He thinks the information in a black hole doesn’t come back out.
Dr. Andy Strominger is a physics professor at M.I.T. He thinks Dr. Hawking is on the right track, although he admits we don’t have a full solution to explain how information can get out of a black hole. But he does think it’s a very important problem to try and solve.
Dr. Don Page from the University of Alberta was working with Dr. Hawking thirty years ago, when the question of what happens to information in a black hole was originally raised. He has challenged Dr. Hawking on this issue for a long time, and is happy to see him switch to the position Dr. Page has held since the early eighties.
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New Human Species
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Homo floresiensis, Courtesy Dr. P. Brown |
The stunning discovery of a new species of human was announced this week. The find was remarkable as a whole new species of tiny primitive humans, but also because this group apparently survived far longer than any other human cousin - perhaps still living as recently as 12,000 years ago. The nearly complete skeleton of an adult female and the partial remains of several other individuals were discovered in a cave on the Indonesian island of Flores. These people were only about one meter tall, with brains about the same size as that of a chimpanzee. Nevertheless, they may have used advanced tools. This remarkable find is going to lead to a major revolution in our thinking about our human lineage. Dr. Peter Brown led the team of researchers that described the fossil in this week’s edition of the journal Nature. He’s an associate professor of paleo-anthropology at the University of New England in Armidale, Australia.
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The Bird Nose Knows
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Pachiptila desolata - Courtesy, Science |
Some birds use their sense of smell to locate their nests in the breeding colony, according to new research. Dr. Gabrielle Nevitt is an associate professor of neurobiology, physiology and behaviour at the University of California, Davis. She studied Antarctic prions who take turns staying with the egg while the mate goes off to sea foraging for up to two weeks. Her findings suggest that the birds can distinguish the scent of their mate from the other birds in the colony and use their sense of smell to pick out the right burrow.
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Junking DNA
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Junking mouse DNA |
Our genomes contain billions of individual molecules, all part of nature's recipe for organisms. Only a portion of the genome, however, is the code for the genes. The rest was once described as "junk dna", but we've since learned that parts of this non-coding DNA are actually quite important. For vast other sections, though, there's no clear function. Dr. Edward Rubin, the director of the U.S. Department of Energy's Joint Genome Institute at Lawrence Berkeley Laboratory at the University of California, designed an experiment to test whether some DNA in a mouse is essential or excess. He was able to completely delete 3-million bases from the mouse's genome with no apparent effect on the mouse.
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