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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

#721

Post by mirimir »

saalweachter wrote: post #658
mirimir wrote: post #590

Earlier quoted context omitted.

You just blew my mind ;) What do we know about the gas giants' cores?

Gas giant cores are weird . Based on models of solar system formation, we're like, pretty sure they started with rocky (or icy) cores that were dozens of times bigger than Earth. But we're not sure they're still there. Due to the intense conditions inside a gas giant, we're not sure if they still have a rocky core, or if the cores have liquified or even convected away to mix with the gasses. So the answer could be "t…

Thanks. I asked because searching seemed to be telling me that we have only theoretical arguments about gas giants' cores. That surprised me at first, but then I realized how little data we probably have. Basically, mass and its distribution, plus spectroscopic data about surface composition, right?

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

#722

Post by samuel »

rubicon33 wrote: post #9

I was reading up about earth alternatives recently, and upon realizing the distance was always going to limit us, no matter how perfect the planet, I realized we need to travel at the speed of light. I think our "best shot" at that right now, is to digitize humans. If we could store consciousness in binary, we could then transmit it at the speed of light (like we do with data every day!). You'd need a receiver on the…

Why humans? People are concerned about the survivability of human species, and it's certainly a noble goal, but at this point it's outside or technological reach. Preserving life, in the other hand, could be doable. We «just» need to take some prokaryotic cells to one of those planets, assuming they have the right environment, and in some million years you have a complete ecosystem...

Assuming also, of course, that there is not life there already.

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

#723

Post by IndianAstronaut »

_lbaq wrote: post #131
noobermin wrote: post #121

Earlier quoted context omitted.

One of the callers (a biologist, so not a crackpot) on TV suggested that given how close the planets were, he wondered if it were possible for there to be cross contamination between the planets given how close they are to each other. He referred to them being part of the same "ecosystem." I'm not sure how feasible that is as a non-astrobiologist, but it is an interesting idea.

Very likely, since this happens between Mars and Earth: https://en.wikipedia.org/wiki/Martian_meteorite

Considering the time scales involved, it wouldn't surprise me if multiple planets around nearby stars happened to be seeded with earth based bacterial/archaea life.

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

#724

Post by iamjeff »

jimmaswell wrote: post #558
dcposch wrote: post #496

Earlier quoted context omitted.

> 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/

If you liked this, you'll probably also like MelodySheep's Symphony of Science series. https://www.youtube.com/watch?v=zSgiXGELjbc

This brought me to tears, literally... There is a beauty to the words that is hard to describe other than to say it gives "meaning" (for lack of a better word) to life on this rock.

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

#725

Post by Sharlin »

mirimir wrote: post #721
saalweachter wrote: post #658

Earlier quoted context omitted.

Gas giant cores are weird . Based on models of solar system formation, we're like, pretty sure they started with rocky (or icy) cores that were dozens of times bigger than Earth. But we're not sure they're still there. Due to the intense conditions inside a gas giant, we're not sure if they still have a rocky core, or if the cores have liquified or even convected away to mix with the gasses. So the answer could be "t…

Thanks. I asked because searching seemed to be telling me that we have only theoretical arguments about gas giants' cores. That surprised me at first, but then I realized how little data we probably have. Basically, mass and its distribution, plus spectroscopic data about surface composition, right?

Juno is hopefully going to tell us more :)

https://en.wikipedia.org/wiki/Juno_(spacecraft)#Scientific_o...

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

#726

Post by nilson »

samuel wrote: post #722
rubicon33 wrote: post #9

I was reading up about earth alternatives recently, and upon realizing the distance was always going to limit us, no matter how perfect the planet, I realized we need to travel at the speed of light. I think our "best shot" at that right now, is to digitize humans. If we could store consciousness in binary, we could then transmit it at the speed of light (like we do with data every day!). You'd need a receiver on the…

Why humans? People are concerned about the survivability of human species, and it's certainly a noble goal, but at this point it's outside or technological reach. Preserving life, in the other hand, could be doable. We «just» need to take some prokaryotic cells to one of those planets, assuming they have the right environment, and in some million years you have a complete ecosystem... Assuming also, of course, that t…

The whole idea of digitizing humans is silly. It would lead to spooky action at distance. For example what if when humans are digitized you send it to two different machines? Which one would be the real you?

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

#727

Post by 4_more_ken »

Symmetry wrote: post #385
wallace_f wrote: post #260

Earlier quoted context omitted.

What determines my speed limit? Is it set at 0 here on earth? What if I travel to another galaxy, this one was going at .5c relative to me when I was on earth. Then after trillions of years, inflation causes all of the galaxies to separate beyond sight from me in this new galaxy. Now, the centre of this galaxy appears at rest. Does my velocity get "reset?"

Special relativity says that no matter what your velocity is relative to Earth you can proclaim that you're actually at rest and it's the other guy that's moving. So your velocity is always continuously being "reset". And in each of the frames of reference of everything in existence nothing else is traveling faster than the speed of light.

The 1905 Special Relativity Theory (1905 SRT) version of reciprocity implies that the other guy in a different inertial frame than your own will be the one that is moving. The consequence of this implication is the "Twin Paradox" (i.e. both twins in different inertial frames have been accelerated and are both aging slower than the other twin). A different version of reciprocity that implies that the accelerated twin is moving and the apparent movement of the twin that has remained stationary is only an aberration (or mirage) is axiomatic because movement first requires acceleration.

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

#728

Post by pault »

aseipp wrote: post #602
Exofunctor wrote: post #471

Earlier quoted context omitted.

> fleeing the earth is not one of them Why not? If a big asteroid is going to hit earth (for example), fleeing is a pretty reasonable response. It's also a reasonable defense against technobiological hazards.

Let me ask you this question: Would you consider the Titanic, oh, I don't know -- a success story? Because that's basically what this sort of thing comes down to, at the end of it. There's basically nothing that is going to be existentially, immediately threatening to earth on a timescale that Mars is actually a more livable environment. Where else in the Solar System could we even get the amount of water we would ne…

Isn't Mars full of water? Source: I read the Mars trilogy by Kim Stanley Robinson.

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

#729

Post by Dove »

tempestn wrote: post #593
Dove wrote: post #551

Earlier quoted context omitted.

> 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

He appeared to be speaking of a known, ongoing crisis, not a minute possibility of a killer meteor.

Haha! My link doesn't go to a video about meteors. Your point is taken, though. I was just being cute and/or hoping you hadn't heard about this.

But I have heard the possibility of a GRB discussed seriously as a motivator for expanding, not just through the solar system, but through the galaxy.

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

#730

Post by Dove »

drzaiusapelord wrote: post #706
Dove wrote: post #551

Earlier quoted context omitted.

> 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 deploy…

The resources involved in preventing a GRB from hitting us, on the other hand, are . . .

. . . actually I have absolutely no idea how you would practically do that at all.

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