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

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

#381

Post by dwaltrip » Wed, Jun 19, 2019, 2:42 PM UTC

codesushi42 wrote: post #351

dwaltrip wrote: post #342

Earlier quoted context omitted.

They are referring to a single system... Here is the quote: >> And to think that there is likely an Easy Mode system out there. >> A habitable planet on the low end of the mass spectrum needed for a stable atmosphere with other habitable planets in-system. And all that close to another star with habitable planets, possibly in the sub-lightyear range. Yes, they mentioned another star system as an additional point, but…

> We have the technology today to launch boulders weighing hundreds of tons to Mars. You must be joking, or you are completely unaware of Tsiolkovsky's equation.

https://en.m.wikipedia.org/wiki/BFR_(rocket)

100+ tons to Mars. Doesn't require any major technological breakthroughs. It's just really big.

If you want a rocket that has already been built, the Saturn V could have launched a ~50 ton boulder to Mars. Not quite hundreds of tons, but that was also built 50 years ago.

If the Earth was suddenly facing interplanetary war with Mars, I imagine we would start building some very impressive rockets quite quickly. And they would all obey the rocket equation :)

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

#382

Post by EGreg » Wed, Jun 19, 2019, 2:49 PM UTC

vageli wrote: post #372

EGreg wrote: post #146

Earlier quoted context omitted.

Assuming a uniform distribution, the probability is 1/365 for any person#. Those probabilities add up linearly if the people are guaranteed to have different birthdays (union/OR). Otherwise the probability of NOT having someone with the same birthday goes down exponentially as a an exponential power of the fraction 364/365 (intersection of complement/AND NOT) It’s exactly what you would expect from classical combinat…

> Assuming a uniform distribution, the probability is 1/365 for any person#. Those probabilities add up linearly if the people are guaranteed to have different birthdays (union/OR). Otherwise the probability of NOT having someone with the same birthday goes down exponentially as a an exponential power of the fraction 364/365 (intersection of complement/AND NOT) Why would we assume a uniform distribution of birthdays?…

To simplify. Mathematical models don’t perfectly capture all the details usually.

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

#383

Post by asdfpoiu10 » Wed, Jun 19, 2019, 3:44 PM UTC

420basteit wrote: post #332

rdm_blackhole wrote: post #306

Earlier quoted context omitted.

> While finding intelligent life would be great, finding any life is nearly as great. That would actually be worrisome. If we found and detected microorganisms on nearby planet e.g 12 light years away from earth, then that means we are probably headed for extinction. The reason is the theory of the Great Filter. Given that we have not been able to observe any kind of activity outside of our solar system, it means tha…

I think you have a slight misunderstanding about the great filter. If we found only microorganisms on the other plant that should indicate that the filter is behind us, life having died out on that planet before even reaching large scale organisms let alone technology. If we find ruins of civilization and technology on the planet at either about the same stage as us or more advanced, then we can assume that the filte…

Not so. All we know from finding micro organisms (or any other form) is that the filter is after that stage. It may well be between micro organisms and us but that seems unlikely.

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

#384

Post by riffraff » Wed, Jun 19, 2019, 4:38 PM UTC

programd wrote: post #223

riffraff wrote: post #60

Earlier quoted context omitted.

I've read that most of Lovecraft's is derived from the horror at realizing how insanely large in both space and time the universe is. The unspeakable horrors and mind defying deities in his oeuvre are effectively just reiteration of the "the human race is an irrelevant blip on the universe's radar" concept.

Well that just cries out for a quote :) "We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either g…

beautiful, thank you!

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

#385

Post by the8472 » Wed, Jun 19, 2019, 5:57 PM UTC

Retra wrote: post #299

the8472 wrote: post #283

Earlier quoted context omitted.

The pressure range range between vacuum, mars atmosphere and earth atmosphere is 10⁵Pa. The pressure at the bottom of the ocean is 10⁸Pa. Humans can survive the former with little more than strong tensile garment and a breathing apparatus, the latter requires massive, crumple-resistant pressure vessels around everything.

Finally someone with the sense to realize what difference an order of magnitude can make to a decision. Now lets compute how likely we are to die by an asteroid vs how likely we are to die being stranded on a barren, frozen rock 60M Km away from the nearest source of critical supplies.

That depends on your time horizon. Probabilities of catastrophic events tend towards 1.0 individually. But within the same time horizon you can keep it close to 0 with sufficient redundancy and recovery.

So the tradeoff would be risking a finite amount of human lives in the short term to reduce the risk of a total loss in the long term. I.e. over time it becomes fixed vs. fractional cost.

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

#386

Post by nurettin » Wed, Jun 19, 2019, 5:58 PM UTC

Dylan16807 wrote: post #296

nurettin wrote: post #220

Earlier quoted context omitted.

Do you acknowledge the fact that interstellar travel entails more than just speeding up and slowing down? Because that's what Dyson would be telling you if he were here.

You need a nuclear-powered airtight bunker that can sustain dozens of people, but that's also buildable with 70s technology. Once you have propulsion and a ship you're pretty well there.

You will essentially kill dozens of people once they hit an interstellar cloud with anything bigger than a sugar molecule at 2/5c.

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

#387

Post by codesushi42 » Wed, Jun 19, 2019, 7:05 PM UTC

dwaltrip wrote: post #381

codesushi42 wrote: post #351

Earlier quoted context omitted.

> We have the technology today to launch boulders weighing hundreds of tons to Mars. You must be joking, or you are completely unaware of Tsiolkovsky's equation.

https://en.m.wikipedia.org/wiki/BFR_(rocket) 100+ tons to Mars. Doesn't require any major technological breakthroughs. It's just really big. If you want a rocket that has already been built, the Saturn V could have launched a ~50 ton boulder to Mars. Not quite hundreds of tons, but that was also built 50 years ago. If the Earth was suddenly facing interplanetary war with Mars, I imagine we would start building some v…

BFR is unproven, no one knows whether it could take a payload of hundreds of tons.

But yeah, in theory you could just build a bigger rocket. But even going from 50 to 100 tons increases the size significantly, let alone going to hundreds of tons like you said. Maybe that's not possible with today's technology, multi stages and all.

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

#388

Post by [deleted] » Wed, Jun 19, 2019, 11:59 PM UTC

EGreg wrote: post #382

vageli wrote: post #372

Earlier quoted context omitted.

> Assuming a uniform distribution, the probability is 1/365 for any person#. Those probabilities add up linearly if the people are guaranteed to have different birthdays (union/OR). Otherwise the probability of NOT having someone with the same birthday goes down exponentially as a an exponential power of the fraction 364/365 (intersection of complement/AND NOT) Why would we assume a uniform distribution of birthdays?…

To simplify. Mathematical models don’t perfectly capture all the details usually.

[deleted]

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

#389

Post by svd4anything » Thu, Jun 20, 2019, 3:52 AM UTC

8note wrote: post #349

svd4anything wrote: post #328

Earlier quoted context omitted.

> d) Food and life support sustainability Could we just send frozen embryos of humans and then have the ship auto thaw and gestate them 16 years to arrival? With another 2-300 years of technological progress this doesn’t seem outlandish mission at all.

that sounds highly unethical. none of those people agreed to go on the trip

did any of us agree to go on our current trip? I do see your point but I think eventually humans might do it.

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

#390

Post by 8bitsrule » Thu, Jun 20, 2019, 5:59 AM UTC

superpermutat0r wrote: post #145

Eupolemos wrote: post #135

Earlier quoted context omitted.

I think current technology makes no sense when talking about interstellar travel. I wonder how long it'd take, seen from the perspective of the ship, if we had an engine capable of delivering a constant 1g acceleration. That's the way we'll want to travel, after all.

constant 1g acceleration gets you to speed of light pretty quickly (around 1 year), so still around 12 years.

Course, assuming you want to orbit your destination when you arrive ... at some point you'd need to turn that 1g in the opposite direction to decelerate. (And I'm mighty impressed by the energy source that provides two years of continuous thrust.)