Two potentially life-friendly planets found orbiting a nearby star • Hacker News Board

Re: Two potentially life-friendly planets found orbiting a nearby star

#81

Post by m4rtink » Tue, Jun 18, 2019, 2:52 PM UTC

api wrote: post #32

petercooper wrote: post #20

"just 12 light-years away" I love the "just". I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-)

Look into Project Orion. With thermonuclear bombs you could hit 8% c, which would get you there in "only" 150-200 years including acceleration and deceleration time. That is still beyond humans with present day life spans, but extend life span to ~1000 years or go full AI and you can totally ride the "devil's pogo stick" to stars Fusion rockets would probably be better. I mention Orion because we sort of know how to…

Nuclear salt water rocket would likely be even faster, but unlike Orion is still just a paper concept at this time.

Re: Two potentially life-friendly planets found orbiting a nearby star

#82

Post by quakeguy » Tue, Jun 18, 2019, 2:53 PM UTC

pault wrote: post #55

__MatrixMan__ wrote: post #19

Earlier quoted context omitted.

Tidal locking means that the denser side of the lighter body always faces the heavier body, and the less-dense side of the lighter body already faces away from the heavier one. The moon is tidally locked to the Earth, which is why it has a dark side.

So the Apollo "earthrise" photos are just "earth"?

Yes, Earth does not move significantly on the moon sky, if i remember right. It does rotate though.

Edit: Archgoon is right, the photos were taken from the orbiting module, so a rise happened.

Re: Two potentially life-friendly planets found orbiting a nearby star

#83

Post by rossdavidh » Tue, Jun 18, 2019, 2:53 PM UTC

mihaifm wrote: post #61

vkaku wrote: post #27

Stop teasing me, Universe - and show me the aliens already!

In this case it’s highly unlikely that there out there, that close, existing simultaneous with us. 4 billion years ahead of us...they’re either long dead or non-existing.

4 billion years, eh? Just about the amount of time we've had life here. Maybe they already colonized us, and we're descended from them.

Re: Two potentially life-friendly planets found orbiting a nearby star

#84

Post by DCKing » Tue, Jun 18, 2019, 2:55 PM UTC

lmm wrote: post #30

petercooper wrote: post #20

"just 12 light-years away" I love the "just". I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-)

> I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-) If we had the political will, the Orion design could get people there in, what, 200 years, and that's with '70s technology.

The Orion program had this potential on paper. Nuclear bomb propulsion is a complicated thing, but we don't understand if it's a feasible propulsion method in practice, like, at all.

Political will in this case brings us more understanding of the feasibility of this propulsion method, but it's way too big of a stretch that political will alone would get us to the nearest starts in 200 years.

Re: Two potentially life-friendly planets found orbiting a nearby star

#85

Post by gambiting » Tue, Jun 18, 2019, 2:56 PM UTC

ekianjo wrote: post #80

pault wrote: post #45

Earlier quoted context omitted.

Going to Mars may be routine some day, though!

Just going to Mars will significantly increase your risk of cancer, unless we find smart ways to repair our genetic material as we go.

Well, for the journey itself the problem has a simple solution - more shielding. Then of course we have to answer the question of how can we get ships into orbit when they are full of shielding, but that's not insurmountable.

The bigger issue is actually living on mars - as romantic as that idea is, human habitation on the surface is really dumb, the radiation level is not insignificant, so anything long term would either have to be shielded or be under ground. And if we are going to build an underground colony....then why not start with one here on Earth?

Re: Two potentially life-friendly planets found orbiting a nearby star

#86

Post by corodra » Tue, Jun 18, 2019, 2:56 PM UTC

lmm wrote: post #30

petercooper wrote: post #20

"just 12 light-years away" I love the "just". I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-)

> I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-) If we had the political will, the Orion design could get people there in, what, 200 years, and that's with '70s technology.

"What if I told you that your family and your next 4 generations of offspring will live on a space ship that'll hopefully reach a distant planet without encountering a massive malfunction due to age or some cosmic phenomenon that'll kill you all? And if that planet is habitable for human life, hopefully it won't have terrifyingly violent lifeforms that'll rape you in the mouth so they can reproduce. Are you interested, very interested or quite interested?"

It's a slightly wee bit more than political will that stops people from wanting to live in a tin can for their entire lives, and their children from living on it...and their grandchildren. All for a "maybe".

Re: Two potentially life-friendly planets found orbiting a nearby star

#87

Post by titzer » Tue, Jun 18, 2019, 2:56 PM UTC

Evidlo wrote: post #65

titzer wrote: post #56

Earlier quoted context omitted.

Why not?

Because then it would be a double planet.

It depends on how big the "main" planet is, I guess. But I think we are running into definitional issues here, and it gets technical very fast. First, IAU does not recognize the term "double planet". Second, a body which is large enough to reach hydrostatic equilibrium (i.e. a sphere) but has not yet cleared its orbit is technically not a planet. So I don't know where this leaves us. A Jupiter-sized planet with an Earth-sized satellite would be such a huge mass and volume difference (an even bigger difference than the Earth and Moon) that it seems to odd to term that a "double planet".

Re: Two potentially life-friendly planets found orbiting a nearby star

#88

Post by lmm » Tue, Jun 18, 2019, 2:57 PM UTC

tictoc wrote: post #50

lmm wrote: post #30

Earlier quoted context omitted.

> I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-) If we had the political will, the Orion design could get people there in, what, 200 years, and that's with '70s technology.

Imagine being the child born on the ship on a crash course to this new planet.

Imagine being the child born on a small island, or in a country to which few other countries are willing to grant visas, or simply to parents who don't have much money.

Re: Two potentially life-friendly planets found orbiting a nearby star

#89

Post by mabbo » Tue, Jun 18, 2019, 2:58 PM UTC

Being that close also offers us a better ability to examine it. The nearer the star, the more arc-seconds (or tiny fractions thereof) the star will appear in telescopes. 12ly is ridiculously close!

It also tells us something interesting. If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitable planets are out there. Only 12ly away and that one has maybe two habitable planets? That tells me the universe is teaming with potential homes for life.

Re: Two potentially life-friendly planets found orbiting a nearby star

#90

Post by kerabatsos » Tue, Jun 18, 2019, 2:59 PM UTC

corodra wrote: post #86

lmm wrote: post #30

Earlier quoted context omitted.

> I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-) If we had the political will, the Orion design could get people there in, what, 200 years, and that's with '70s technology.

"What if I told you that your family and your next 4 generations of offspring will live on a space ship that'll hopefully reach a distant planet without encountering a massive malfunction due to age or some cosmic phenomenon that'll kill you all? And if that planet is habitable for human life, hopefully it won't have terrifyingly violent lifeforms that'll rape you in the mouth so they can reproduce. Are you intereste…

Mouth rape sounds disagreeable.