May 24, 2012
A recent study proposes the galaxy is crowded with nomad planets adrift in space. If this is the case, nomad planets may play a dynamic role in the universe. Titled “Nomads of the Galaxy,” the authors proposed an upper limit to the number of nomad planets that might exist in the Milky Way Galaxy: 100,000 for every star. And because the Milky Way is estimated to have 200 to 400 billion stars, that could put the number of nomad planets in the quadrillions.
“If you imagine the Earth as it is today becoming a nomad planet… life on Earth is not going to cease,” said Dimitar D. Sasselov, Professor of Astronomy at Harvard University and the Harvard-Smithsonian Center for Astrophysics, and the Director of the Harvard Origins of Life Initiative. ”That we know. It’s not even speculation at this point. …[Scientists] already have identified a large number of microbes and even two types of nematodes that survive entirely on the heat that comes from inside the Earth.”
The image at the top of the page is an artistic rendition of a nomad object wandering the interstellar medium. The object is intentionally blurry to represent uncertainty about whether or not it has an atmosphere. A nomadic object may be an icy body akin to an object found in the outer Solar System, a more rocky material akin to asteroid, or even a gas giant similar in composition to the most massive Solar System planets and exoplanets.
Journal reference: Monthly Notices of the Royal Astronomical Society
The Daily Galaxy via The Kavli Foundation
Image credit: With thanks to Greg Stewart/SLAC
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