Water found on a potentially life-friendly alien planet • Hacker News Board

Re: Water found on a potentially life-friendly alien planet

#121

Post by mdgrech23 » Wed, Sep 11, 2019, 10:12 PM UTC

chenning wrote: post #115

A very quick search suggests that earth will become uninhabitable somewhere between 500 million and 2 billion years from now. If we shot a probe to this life-friendly alien planet with some sort of primordial soup, even traveling at the speed of light it would take 4 billion earth years to get there. Do I have that right? Basically we'll never even come close to being around when it finally arrives, if it ever arrive…

Your assumptions may be wrong especially considering how far in the future we're talking.

Re: Water found on a potentially life-friendly alien planet

#122

Post by kadoban » Wed, Sep 11, 2019, 10:12 PM UTC

chenning wrote: post #115

A very quick search suggests that earth will become uninhabitable somewhere between 500 million and 2 billion years from now. If we shot a probe to this life-friendly alien planet with some sort of primordial soup, even traveling at the speed of light it would take 4 billion earth years to get there. Do I have that right? Basically we'll never even come close to being around when it finally arrives, if it ever arrive…

It would not take 4 billion years at the speed of light, it would take 111 years. That's what light-years are, the distance travelled by light in a year.

Re: Water found on a potentially life-friendly alien planet

#123

Post by ben_w » Wed, Sep 11, 2019, 10:14 PM UTC

partiallypro wrote: post #89

sky_rw wrote: post #76

Earlier quoted context omitted.

Not sure the two are comparable. 300lb obese person's bone structure weighs the same, their heart and lungs weigh the same. I suspect 2x the weight on every organ is going to be seriously detrimental for sustained periods.

Not to mention you'd go from years and years of near 0G gravity to twice the gravity of earth. You wouldn't even be able to walk.

Compare to the difficulty of getting there in the first place, getting spin gravity to work right isn’t a big problem.

Re: Water found on a potentially life-friendly alien planet

#124

Post by 0xffff2 » Wed, Sep 11, 2019, 10:14 PM UTC

kadoban wrote: post #122

chenning wrote: post #115

A very quick search suggests that earth will become uninhabitable somewhere between 500 million and 2 billion years from now. If we shot a probe to this life-friendly alien planet with some sort of primordial soup, even traveling at the speed of light it would take 4 billion earth years to get there. Do I have that right? Basically we'll never even come close to being around when it finally arrives, if it ever arrive…

It would not take 4 billion years at the speed of light, it would take 111 years. That's what light-years are, the distance travelled by light in a year.

Strictly speaking, if you actually traveled at the speed of light, the trip would be instantaneous from the reference frame of the craft making the trip. It would still take 111 years from our frame of reference on Earth.

Re: Water found on a potentially life-friendly alien planet

#125

Post by chenning » Wed, Sep 11, 2019, 10:14 PM UTC

kadoban wrote: post #122

chenning wrote: post #115

A very quick search suggests that earth will become uninhabitable somewhere between 500 million and 2 billion years from now. If we shot a probe to this life-friendly alien planet with some sort of primordial soup, even traveling at the speed of light it would take 4 billion earth years to get there. Do I have that right? Basically we'll never even come close to being around when it finally arrives, if it ever arrive…

It would not take 4 billion years at the speed of light, it would take 111 years. That's what light-years are, the distance travelled by light in a year.

Ah, right. Basically I vote for firing a primordial soup probe to this sucker.

Re: Water found on a potentially life-friendly alien planet

#126

Post by Rychard » Wed, Sep 11, 2019, 10:17 PM UTC

dsfyu404ed wrote: post #59

TheOtherHobbes wrote: post #27

Earlier quoted context omitted.

Surface gravity will be around 2g, so even if it has a rocky surface it's not going to be a very comfortable home from home.

So a 150lb person will weigh 300lb. Sure that's gonna suck on day one but there's plenty of people who weigh that much who get by. Without all the health complications from high body fat it wouldn't be that bad. You'd probably die young but I don't think that would bother people.

You're not the only thing that weighs twice as much; everything else does too.

I would imagine the atmospheric pressure would be the most noticeable consequence of this.

The article notes that the planet is substantially larger:

> K2-18b is very unlike our home world: It’s more than eight times the mass of Earth, which means it’s either an icy giant like Neptune or a rocky world with a thick, hydrogen-rich atmosphere.

And the Wikipedia article for "Super-Earth" mentions something relevant:

> a planet with 2 Earth-radii and 5 Earth-masses with a mean Earth-like core composition would imply that 1/200 of its mass would be in a H/He envelope, with an atmospheric pressure near to 2.0 GPa or 20,000 bar

For comparison, the atmosphere on Earth (sea level) is approximately 1 bar.

It looks like the apparent atmospheric pressure on such a planet might be similar to being approximately 200 kilometers below the surface of the ocean on Earth. For additional perspective, the Mariana trench is (I believe) the lowest point on the planet, and is only like 11 kilometers deep.

So I guess what I'm saying, is that the apparent doubling of one's weight would be an insignificant concern in the grand scheme of things.

Re: Water found on a potentially life-friendly alien planet

#127

Post by ghostbrainalpha » Wed, Sep 11, 2019, 10:17 PM UTC

Serious question - Do we have the capability to send human life there now?

Obviously its going to be a one way trip. And it would require a generational ship.

So could we build a ship that held 12 people initially, 6 couples, all who were allowed to have 2 children, so 24 people max, and could we load it with enough supplies to last over 100 years?

Even if the group that eventually arrived had no way to sustain life, and they just went there for a quick swim before dying... is it possible?

Re: Water found on a potentially life-friendly alien planet

#128

Post by 0xffff2 » Wed, Sep 11, 2019, 10:17 PM UTC

chenning wrote: post #125

kadoban wrote: post #122

Earlier quoted context omitted.

It would not take 4 billion years at the speed of light, it would take 111 years. That's what light-years are, the distance travelled by light in a year.

Ah, right. Basically I vote for firing a primordial soup probe to this sucker.

There are people working on the basic technology [0]. It's going to be quite a while before we visit nearby stars though. Even launching a probe that has a reasonable chance of successfully visiting (and communicating back to us!) this star system is probably not going to happen in the lifetime of anyone currently living.

[0] https://en.wikipedia.org/wiki/Breakthrough_Starshot

Re: Water found on a potentially life-friendly alien planet

#129

Post by isostatic » Wed, Sep 11, 2019, 10:17 PM UTC

ajconway wrote: post #18

archgoon wrote: post #4

Earlier quoted context omitted.

It's 111 light years away. For all intents and purposes, that's a one way trip right there; irregardless of the rocket equation. Even at relativistic speeds, you can't come home anymore.

Theoretically, you can. At 0.99c 111 light years take about 15 years of ship time to travel.

accelerating at 1G to the mid point, then decelerating at 1g, will mean you’ll get there in about 15.8 ship years, or 115 earth years.

Spend twice as long on boats though (32 years) and you can do about 10,000 light years.

Re: Water found on a potentially life-friendly alien planet

#130

Post by cody3222 » Wed, Sep 11, 2019, 10:19 PM UTC

chenning wrote: post #115

A very quick search suggests that earth will become uninhabitable somewhere between 500 million and 2 billion years from now. If we shot a probe to this life-friendly alien planet with some sort of primordial soup, even traveling at the speed of light it would take 4 billion earth years to get there. Do I have that right? Basically we'll never even come close to being around when it finally arrives, if it ever arrive…

That's what wormholes are for...