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Close orbit around a relatively cold star. Interesting. I wonder what their 'day' vs 'year' looks like. Also their atmosphere and surface pressure. They could b

• imdsm 10y ago
  If they are tidally locked as reported, then there will be no day, not really. Just as there is no day on the moon.
  • strictnein 10y ago
    The moon rotates once every ~27 days, so its day is ~27 days. It's just in sync with its orbit of the earth, so it appears to us that it doesn't rotate. http://www.space.com/24871-does-the-moon-rotate.html http://www.space.com/24871-does-the-moon-rotate.html
    • visakanv 10y ago
      Isn't that technically the moon's "year"?
      • idbehold 10y ago
        A year generally refers to the time something takes to make one revolution around its closest star.
• idbehold 10y ago
  > Because the planets are so close to Trappist-1, they have quite likely become “gravitationally locked” to the star, always with one side of the planets facing the star, much as it is always the same side of Earth’s moon facing Earth. Also, during the live stream they said that the furthest planet does a complete orbit around the star in 20 Earth days. So there are likely no 'days' on any of these planets and a 'year' goes by in less than a month on Earth.