Sunday, October 5, 2008

Big Bang or Big Bounce?: New Theory on the Universe's Birth


From American Scientist:

Atoms are now such a commonplace idea that it is hard to remember how radical they used to seem. When scientists first hypothesized atoms centuries ago, they despaired of ever observing anything so small, and many questioned whether the concept of atoms could even be called scientific. Gradually, however, evidence for atoms accumulated and reached a tipping point with Albert Einstein’s 1905 analysis of Brownian motion, the random jittering of dust grains in a fluid.

... Physicists’ understanding of the composition of space and time is following a similar path, but several steps behind. Just as the behavior of materials indicates that they consist of atoms, the behavior of space and time suggests that they, too, have some fine-scale structure—either a mosaic of spacetime “atoms” or some other filigree work.

Material atoms are the smallest indivisible units of chemical compounds; similarly, the putative space atoms are the smallest indivisible units of distance. They are generally thought to be about 10–35 meter in size, far too tiny to be seen by today’s most powerful instruments, which probe distances as short as 10–18 meter. Consequently, many scientists question whether the concept of atomic spacetime can even be called scientific.

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