“The formation of planets is one of the major unsolved problems in modern astrophysics.” That’s how Rafael Millan-Gabet at Caltech and John Monnier from the University of Michigan begin their account of how our understanding of planet formation is about to undergo a revolution.
Driving this change will be a new generation of telelscopes and techniques capable of measuring and in some cases imaging planet formation in action.
It’s worth pointing out the poverty of our current understanding. At the heart of the problem is the fascinating question: why are all the planets different?
The ones in our solar system ought to have formed out of the same stuff at more or less the same time and yet no two are alike. And now the extrasolar planets seem to be demonstrating a similar variety.
The trouble is that astronomers have only the vaguest understanding of what goes on inside the circumstellar discs where planets are supposed to form. They have little idea of the circumstances in which accretion dominates over gravitational instability, whether “dead zones” exist in circumstellar discs where planets cannot form or what mechanisms are at work in transporting angular momentum within early solar systems. They don’t even know when planets form.
The new measurements that will be possible in the coming years should hep to answer at least of these puzzles. And that makes this an exciting field to be in. Watch this space for developments
Ref: arxiv.org/abs/0902.2576: How and When do Planets Form? The Inner Regions of Planet Forming Disks at High Spatial and Spectral Resolution