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Seven earth-sized planets discovered circling a star 39 light years from Earth

nature.com

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Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#701

Post by ooqr »

dcposch wrote: post #496
dmix wrote: post #6

My favourite part of the press release: > The planets also are very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth's sky. > In contrast to our sun, the TRAPPIST-1 star – classified as an ultra-cool dwarf – is so cool that liquid water cou…

> The planets also are very close to each other. If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth's sky. this reminds me of one my favorite films ever. it is just four minutes long http://www.erikwernquist.com/wanderers/

I was very skeptical but pleasantly surprised.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#702

Post by maverick_iceman »

Arizhel wrote: post #698
misnome wrote: post #583

Earlier quoted context omitted.

By the same 'argument', understanding the laws of thermodynamics (which prohibit perpetual motion) allows us to exploit perpetual motion?

No one's talking about perpetual motion here. Understanding the laws of thermodynamics allows us to build heat engines, which is how many of us got to work this morning. It also allows us to build nuclear reactors (or at least the steam-cycle part of it), which is how many of us get the power to write messages here. What does our "understanding" of gravity allow us to do technologically? Nothing, because we have zero…

It's probably futile to argue with you but have you considered maglev trains?

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#704

Post by pharke »

jerf wrote: post #684
pharke wrote: post #681

Earlier quoted context omitted.

What about tidal and geological heating? or a greenhouse effect similar to Venus?

Any heat source exposed to space has the basic problem of its volatiles running away and not coming back. On geological time frames, this effect is probably nearly instant, so it isn't very helpful that maybe a new volcano could pop up somewhere and melt lots of stuff or something, because all that does is put a hole in the permanently frozen layer. Any heat source not exposed to space might harbor life, but that's n…

The link you provided suggests that one of the main ways for carbon to enter the atmosphere or ocean is through volcanic eruptions and geological hot spots. Isn't increased geological activity one of the results of orbital resonance?

If the 'central' planet has 6 close neighbours of equivalent size in resonant orbits would this not provide a very large amount of 'stirring'? These planets are also much more massive than Europa which is only 0.008 times the mass of the Earth compared to ~.6 and ~1.3 Earth masses for the ones in the habitable zone. They may have a more substantial mantle and core, possibly global magnetic fields and definitely more gravity to hold on to any fugitive gasses.

Considering geological timescales, this system is also billions of years younger than our own, potentially only a little over 500 million years old. The processes you draw concern to may simply not have had time to play out yet.

I'm also not convinced that the atmosphere would be cold enough to freeze out gasses on the night side if there were significant oceans or enough atmospheric circulation to transfer heat from the day side.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#705

Post by kbenson »

cstejerean wrote: post #207
noobermin wrote: post #88

Earlier quoted context omitted.

Of course, #askNasa didn't win me a question, but could any astrobiologists comment on this question: Tidal locking means the planets would always have a side facing the star, leading to very different thermodynamics in terms of climate and weather on the planet, not to mention radiation. Doesn't that very much hurt the chances for life on those planets?

Apparently what would hurt the chance of life in a tidally locked planet the most is that due to being tidally locked the planet would have a reduced magnetic field to protect the atmosphere, and therefore there is a good chance that the planet would lose it's atmosphere over time. https://en.wikipedia.org/wiki/Habitability_of_red_dwarf_syst...

Does atmosphere include the ocean? Because life developed in the oceans first here, and some has never left.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#706

Post by drzaiusapelord »

Dove wrote: post #551
tempestn wrote: post #399

Earlier quoted context omitted.

There's no other conceivable extinction event that could occur "a couple years out". If you're talking climate change, then I agree that's a major problem, but on the order of at least decades.

> There's no other conceivable extinction event that could occur "a couple years out". Life on earth could end in the next five minutes. :) https://www.youtube.com/watch?v=RLykC1VN7NY

The resources and practically to gently shoving a comet or asteroid out of the way are probably a billion less than building self-sustaining colonies elsewhere. Worse, now we have two planets to defend, not one.

I don't see the "we must migrate now" types saying "lets put migration away for a while so we can better build anti-asteroid solutions and detection systems."

Arguably, we're just a couple launches and deployments of mass drivers away from fixing this issue. This is all known tech that could be deployed relatively quickly. A self-sustaining Martian colony is probably hundreds of years away considering the work it would take to terraform the planet.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#707

Post by wyager »

Sembiance wrote: post #659
mjevans wrote: post #458

Earlier quoted context omitted.

With a round trip parts delivery time OF a generation, and a communications delay of almost a decade (two for duplex), I don't see any reason not to classify such a mission as a short-range 'generation ship' / complete colony effort. Getting our 'eggs' out of a single cosmic basket is really important, however I think we need to at least take the baby-crawl to establishing an outpost in the asteroid belt. That would…

I feel that advancements in quantum mechanics will solve the communication problem.

No, it almost certainly won't. Our current understanding of quantum information theory simply doesn't allow transmitting classical information faster than light. There's no room in what we don't understand that could plausibly contain FTL communication. This is a pretty fundamental result of quantum information theory. https://en.m.wikipedia.org/wiki/No-communication_theorem

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#708

Post by Balgair »

dragonwriter wrote: post #507
Balgair wrote: post #431

Earlier quoted context omitted.

Well, HN is not the most optimal place to do that. There are not many of us on here and we all already know these things. 1600 Pennsylvania Pl. is a better bang for your buck.

I think you probably mean 1600 Pennsylvania Ave. (not Pl.), Washington, D.C. Though I don't share your assessment that that is a productive place to direct citizen input on this (or any other) issue.

Thanks!

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#709

Post by cstejerean »

kbenson wrote: post #705
cstejerean wrote: post #207

Earlier quoted context omitted.

Apparently what would hurt the chance of life in a tidally locked planet the most is that due to being tidally locked the planet would have a reduced magnetic field to protect the atmosphere, and therefore there is a good chance that the planet would lose it's atmosphere over time. https://en.wikipedia.org/wiki/Habitability_of_red_dwarf_syst...

Does atmosphere include the ocean? Because life developed in the oceans first here, and some has never left.

Without an atmosphere you can't maintain a surface ocean, because liquid water can't exist in a vacuum. It's possible for the ocean to exist under a crust of ice though. See Europa for an example. So it's still theoretically possible for life to exist in a subsurface ocean, but I think it's a lot less likely compared to a planet with an atmosphere and temperatures that would support liquid water on the surface.

Re: Seven earth-sized planets discovered circling a star 39 light years from Earth

#710

Post by alphanumeric0 »

Arizhel wrote: post #421
blueprint wrote: post #330

Earlier quoted context omitted.

You're completely missing my point. We've known about climate change for a long time. Since the 60s/70s, no? But nobody has been able to realize what it really is, because scientists do not understand gravity yet. I've been begging people to confirm this for themselves instead of believing what others say about it. If people really knew what global warming was they would have started working on ships decades ago. My…

You sound a little unhinged to be honest. If you're really worried that climate change on Earth is going to cause big problems for humans (which is not an unreasonable concern; climate change threatens to cause significant sea level rise which will cause big problems for people living in sea-level coastal cities), building self-sufficient colonies offworld is a rather extreme answer to that. A simpler answer is to si…

So all we have to do about climate change is build structures to handle extreme weather? Climate change is and will continue to affect our whole food chain that supports the some ~7 billion people on earth. It's not just the weather we will be dealing with.
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