The best bits from the NASA AMA following the announcement of Trappist-1 exoplanets

Nasa just announced the discovery of 7 Earth sized exoplanets in orbit around the ultracool white dwarf star Trappist-1. All the planets are in orbit closer to the star than Mercury is to our Sun. If the star was as hot as our Sun, the planets would have been hot, dry deserts. However, as the star is much cooler, the planets bask in a comfortably warm temperature. Three of the planets are in the habitable zone, which means liquid water can exist on the surface. Following the announcement, Nasa scientists responded to questions in a Reddit Ask Me Anything (AMA) thread. Here are the best questions and responses.

    1. NASAJPL

      The fact that the planets are really tightly packed is at the basis of lots of exciting thoughts. First, this allow for material transfer way either than in our planetary system. This means that rocks, and anything on/around them, could be sent/transfer easily from one planet to the next. So if a few of these planets were habitable, we can theorize about the idea of a microbial biomass colonizing different planets, then evolving independently.. Another brilliant thing to theorize about is “how would civilizations evolving with large bodies with way more structures than our Moon crossing their sky would be affected by these bodies, by Space?”..

      Possibilities are endless!

      J.d.W.

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  1. TheiPortal

    If some of the planets are close enough to appear moon sized to each other, then what sort of gravitational relationship do the planets have?

    Would these planets have a relationship similar to that of the Earth and the Moon? (One orbits the other.)

    Or is it possible that the planets may eventually collide with one another due to the similar strength of gravity?

    1. NASAJPL

      The planets will have some significant tidal interactions. We already know that their orbits are perturbed by mutual gravitational interactions as we see variation in the timing of transits. Simulations have shown the planet orbits should be stable so it is unlikely that they would collide. — Sean Carey

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  1. cellularized

    Is there any real chance we could learn in our lifetime if there’s life (and to what degree of complexity) on one of this planets?

    1. NASAJPL

      We will have the tools (the James Webb Space Telescope and the Extremely Large Telescopes) to start looking for signs of life in the next decade(s). So this is a very exciting time for current and future astronomers!

      J.d.W.

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    1. NASAJPL

      No, actually visiting TRAPPIST-1 is a very, very far future concept. But more observations to learn more about these planets are planned! -G.A.

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We’re NASA scientists & exoplanet experts. Ask us anything about today’s announcement of seven Earth-size planets orbiting TRAPPIST-1!

  1. csrabbit

    Why are exoplanets named with just numbers and letters? Don’t you feel like there would be more interest if they were given “real” names?

    I know I would definitely be more interested.

    1. NASAJPL

      That would be lovely, but difficult to implement. Imagine how to come up with thousand of different names and then remembering them.. Here, the star gives the central part of the name then one decline it with letters. Not “exciting” but convenient 😉 J.d.W.

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  1. juniorlax16

    Maybe I read/watch too much Sci Fi, but why do all predictions for “the potential to sustain life” assume oxygen and liquid water? Couldn’t a different (read: alien) lifeform evolve that could breathe, say, methane, or not require as much water to survive?

    1. NASAJPL

      That’s a great point–what we really should say is, “the potential to sustain life as we know it.” We tend to talk in those terms because we know a lot about what makes it possible for life as we know it to exist. However, you are absolutely right–what about life as we DON’T know it? That is a lot more difficult question b/c sort of by definition, we don’t know anything about the conditions needed to support life as we don’t know it. Nevertheless, even if you don’t hear as much about it, there is a very active branch of Astrobiology that is focused on figuring out how we might be able to identify life with a fundamentally different biology/biochemistry from life on Earth. Hopefully, by the time we have the tools to look for the signs of life on an Earth-like exoplanet, we will know a lot more about how to recognize both life as we know it AND life as we don’t know it. DMH

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