Atmospheres may be the key to day and night for alien planets

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Alien planets that orbit close to their parent stars may be at high risk of the ultimate hot-cold scenario, with one side stuck in permanent daylight while the other shrouded in everlasting night. But a thin atmosphere may be enough to save a planet from this fate, new research shows.
Living on a planet with one side in perpetual sunlight and the other in perpetual darkness would pose some significant challenges for survival — the sunny side of the planet might reach boiling temperatures while the dark side might be completely frozen.
This scenario occurs when a planet's rotation (its day) becomes synched with its orbit (its year), meaning only one side of the planet ever faces its parent star. Earth's moon experiences this "synchronous rotation," which is why only one side of the moon ever faces the Earth. Some researchers fear that many of the new exoplanets being discovered around other stars are at risk of experiencing this synchronous rotation, which might lower the odds that those planets support life Read more...
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