Fresh Dust?

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The last few years have seen a good deal of excitement among astronomers over the possibility of discovering planets orbiting distant stars. Astronomers are looking at stars that are surrounded by disks of dust and debris.

The idea is that planets form over millions of years from the dust and rock that orbits a star. This was supposedly how the Earth formed billions of years ago. Hundreds of such stars have so far been identified. Often, these debris fields extend further from the star they orbit than, say, Pluto is from our sun. The question is, are the discovery of planets and debris around other stars proof of evolution's story of the formation of the Earth?

Scientists believe that it takes two or three million years for planets to form out of the orbiting debris. However, they also recognize that it only takes a few thousand years before a star's gravity draws the dust into itself, or the pressure of its radiation forces the dust away from itself. This leaves the hundreds of stars with dusty debris fields a mystery. Astronomers believe that all these stars still have their dust after millions or billions of years because they are getting fresh dust from somewhere else, but scientists don't know where.

Perhaps a better explanation is that these stars are only about 6,000 years old.