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Two potentially life-friendly planets found orbiting a nearby star

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

#312
post #30

"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.

If you enjoy the idea of propelling space ships using nuclear explosions, look up nuclear salt-water rockets (NSWRs, or Zubrin Drives). The idea is to dump pipes full of sub-critical amounts of radioactive salts out engine, combining outside the ship in a continuous nuclear explosion.

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

#313
post #105

Earlier quoted context omitted.

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. If regular travel becomes a reality, you wouldn't shield the launch vehicle, but the cycler[1]. [1] https://en.wikipedia.org/wiki/Mars_cycler

The benefit of using a cycler rather than a ship that travels orbit-to-orbit is that there is no need to accelerate/decelerate the mass of the ship, just the perishables (people and provisions for the voyage) You would accelerate a small vessel (like a crew dragon or orion), intercept and dock with the much larger cycler, then enter the ship for your x-month trip. When you near mars, you get back into your dragon, an…

> You could presumably look at using a small asteroid to provide the bulk of the "cycler", offering plenty of shielding for the trip, you'd only have to get it into position once - far less fuel requirement.

Or maybe even something like, as some have suggested (not me!), Phobos:

http://enterprisemission.com/Phobos.html

Warning: it's kind of out there. At the very least, it's perhaps interesting as speculative sci-fi.

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

#315

Earlier quoted context omitted.

> So if they were inhabited, what happened to them? Are they exactly at our level of development? Earlier? Hopefully. Because later poses some real big questions - does technology top out about where we are now - no FTL travel, no really big radio transmitters or stellar engineering? No probes to nearby star systems? Did they even make it past the nuclear age, or avoid wrecking their climate? You get more than one ch…

> 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…

Have we done anything that we'd be able to detect from 12 ly?

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

#317

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…

Have we done anything that we'd be able to detect from 12 ly?

Our radio transmission bubble is far beyond 12ly. The question is how sensitive an instrument we'd need to detect it. IIRC, there are some pretty big bursts in ther along with the general noise.

There'd also be significant signatures in the composition of our atmosphere.

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

#318

Earlier quoted context omitted.

I had high hopes, but TBP is a terrible novel. It certainly has some fascinating ideas, but just as many ludicrous ones that are equally central to the plot. Not to mention Liu is absolutely terrible at anything relating to characters: dialogue, character development, etc.

Over in the s-f subreddits, this novel gets so much love. So I feel left out that I - like you few here - really hated it. My big thing was that the science is just wrong . Most fundamentally, it's not a three-body problem, there are (at least) four bodies: the three suns and the planet. And the real world isn't going to follow any theoretical solution to TBP anyway. There is atmospheric drag, microscopic gravitation…

I don't understand your opposition to the name. The three body problem is so named precisely because it's intractable. In physics with two bodies you can perfectly model the evolution of a system, but as soon as you add a third it becomes chaotic and requires numerical simulation to approximate solutions.

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

#319

I saw a study recently, unfortunately I can't locate it now. It discussed the possibility of there having been past civilizations on Earth, hundreds of millions or even billions of years ago. The conclusion was that this can't be entirely ruled out. It noted how few actual fossil remains we have for what we know of dinosaurs, and that there's a lot of space left in those gaps for all the evidence to have been destroy…

I am not a geologist, but it seems improbable for a technical civilization (like our current one) to not leave a global geological mark. For example, our use of fossil fuels changed global carbon isotope composition: our atmosphere now has less portion of C13, because photosynthesis favors the lighter C12 atoms, and all our fossil fuels ultimately derives from photosynthesis.[1] The changed isotope ratio will be dete…

Look up the PETM (Paleocene Eocene Thermal Maximum), there's definitely a d13C signature there.

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

#320
post #89

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 habitab…

Yes 12 ly is amazingly close! > 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 I would put a slight caveat to this - I would argue we do know there's something "special" about our little corner of the galaxy , at least - we are in the continuously habitable zo…

I often hear about the LY unit of distance. Why is it that we are still discovering things which are close to us in LY units? Wouldn’t we discover things at a distance of 5xLY before discovering things at a distance of 100xLY?
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