NASA finds seven Earth-sized planets around a single star

[Disembodied]

https://www.nasa.gov/press-release/nasa ... ets-around

NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.

[Cody]

All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. The planets also are very close to each other.

That's a crowded system! An ultra-cool dwarf, eh?

[Disembodied]

An ultra-cool dwarf, eh?

That could mean the system is very, very old, compared to our own … it could also mean that the planets in the habitable zone are tidally locked.

[Cody]

<nods>

[spud42]

read this earlier today. they highlight Trappist-1 d with a 3d model. you would be able to see 2 or 3 of the other planets at night!
only problem i see is the year is only 18.2 days!! thats some speedy planet.

[tsoj]

the problem for possible life is that theyre most likely tidally locked which can causes extreme temperatures and so extreme wind.

[spud42]

i read that as well, but didnt they recently find that Mercury is not tidally locked? so there is a chance these are not.

[Disembodied]

i read that as well, but didnt they recently find that Mercury is not tidally locked? so there is a chance these are not.

True, but Mercury is six times farther from the sun than the outermost planet is from Trappist-1. Then again, Trappist-1 is a lot less dense than our sun. The only way we'll know for sure is if we go there and find out!

In the meantime, the Trappist-1 system has a website of its own:
http://www.trappist.one

[Cody]

More news on this system at El Reg.

[Disembodied]

It might be possible to warm one of the snowballs up a bit, with one of these - a prototype engine using the Leidenfrost effect on frozen CO2 to power an engine:

https://www.eng.ed.ac.uk/about/news/201 ... -life-mars

[Cody]

Energy from dry ice? Interesting!

[Cody]

Boffins now reckon they're probably a bunch of water worlds.

[Malacandra]

And when they say "water worlds" they mean literal globes of water with a solid core. Earth's proportion of water is about what you'd get if you picked a pool ball out of a bucket of water (a couple of miles depth on a 4000-mile radius is almost literally just a film of water, in planetary terms).

[Cody]

<nods> Yep, not a lot of water on planet Earth.

[Malacandra]

Indeed. Trouble with all that water is you need some dissolved solids as well to make bio-compounds out of, I think - you can't get very far with just water and a reducing atmosphere. And possibly some shallows for the reactions to occur in.