Science News : How to make planets. In theory. Maybe too in reality.
Monday, March 28th, 2011
One of the greater puzzles in planetary science is how, exactly, do the processes that form stars also provide planets to orbit them?
After all, simply discovering extrasolar planets has gotten to be routine. The count is at 531 (so says NASA) and the agency’s Kepler orbiting telescope, staring at 156,000 stars for signs of planetary transits that slightly but abruptly dim their shine, has a list of more the 1200 more candidates. Most seem likely to be verified.
Such observations are bound to get more exciting as new instruments and further observations eventually make clear how many planets that resemble Earth are out there. None with a close kinship have been found yet – Earth is small and on an orbit that takes longer then most found so far. Sooner or later we’ll know whether worlds with water and conditions as hospitable for life as Earth is (for life as we know it) are common. That will be big news. Maybe we’re in a very rare place. Maybe we have a lot of company. Stay tuned.
In the meantime, theorists are getting more ideas why planets exist at all. A few reporters are paying close heed. Some report on planetary possibilities around distinctly non-sun-like stars.
Stories:
- Science News – Ron Cowen: Planets take shape in embryonic gas clouds / New theory of planetary formation may explain variety ; Cowen cites several papers, on line at the arXiv site and due soon for journal publication. He also links to an impressive animation stemming from a computer model by a team in the UK. A frame is in the image above. The theory’s twist is that gas clumps, not aggregations of small solid bodies, are the first steps toward planetary formation – and also provide a way for planets to wind up very close to their stars. Back in January, Cowen forthrightly shares with us, at Scientific American George Musser filed a blog post laying out the ferment in planetary formation theory colorfully – and included there word of the theory Cowen highlights this week. Cowen says he wrote his story then discovered that Musser had been there first.
- PhysOrg.com – Deborah Braconnier: Habitable planets and white dwarfs ; Far out speculation about chances planets might form around or get captured by white dwarfs (which are massive but smaller than many planets).
- Discovery News – Ian O’Neill: Could dead stars support life? ;
- ABC (Australia) Stuart Gary: Dead stars may harbour Earth-like planets ;
- Charlie Petit