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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: 'Super-Earths' May Not Be So Super for Life
26 February 2014 2:00 pm
A nice neighborhood doesn’t necessarily guarantee that your house is livable. Likewise, even if a planet orbits within the so-called Goldilocks zone surrounding its parent star where conditions are neither too hot nor too cold, its atmosphere may be hostile to life, a new study suggests. Even “super-Earths,” orbs with masses that fall between one and 10 times that of our planet (depicted at right in the artist’s concept above) and therefore offer some semblance of similarity to Earth, might be uninhabitable. Using computer simulations, researchers modeled the growth and evolution of a variety of planets as they and their sunlike parent star coalesced from a cloud of whirling gas and dust. In most scenarios, planets that started with a rocky core between one-tenth and one times the mass of Earth lost their hydrogen-rich protoatmospheres 100 million years or less after the dust and gas surrounding the nascent star had dissipated, researchers report online this week in the Monthly Notices of the Royal Astronomical Society. That forfeiture, driven by the intense ultraviolet radiation streaming from the young parent star, offered those planets the chance to develop a more hospitable atmosphere later in their lives (either from gases later emitted from the planet itself or gained via the impacts of comets and asteroids), the researchers note. But in many instances, the simulations show, even planets starting with rocky cores as little as 1.5 Earth’s mass may trap and hold atmospheres containing between 100 and 1000 times the amount of hydrogen found in the water in Earth’s oceans—thick, dense envelopes exerting pressures so hellish that life on the planets’ surfaces might be almost impossible.