Thursday, March 13, 2008

Growing Planets

One of the big problems in planetary formation is getting rocks to stick together. The basic idea is that the swirling gases and particles going around a star eventually make their way to being planets. We basically understand how small particles start to stick together to make bigger particles, and we can certainly figure out how little planets coalesce in order to make big planets, but somewhere in between particles and small planets we get a little hazy.

Our understanding is not helped all that much by a dearth of observations for this "in-between" stage of rocks going around a star, because little rocks don't reflect too much of the stellar light. Additionally, this "in-between" stage is fairly short-lived, which already puts at a disadvantage to observing.

Fortunately, a group led by William Herbst just announced in Nature today evidence of a 3 million year old star with sand-sized grains around it. This helps push forward the understanding of planet formation, which should also give us information on the abundance of planets, and what stellar systems are the best candidates for looking for planets. A little bit more observational data never hurt planet formation theorists (well, it hurts, but only at first.)

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