Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

An extrasolar world covered in water?

nouvelles.umontreal.ca

Post reply on HN
Print view View original

51–60 of 150 posts

Re: An extrasolar world covered in water?

#51

Post by hoosieree »

ryandrake wrote: post #21
prox wrote: post #15

Earlier quoted context omitted.

We can’t do lightspeed with the best tech available, so it’s more like 300-400 years probably.

Don't have to go light speed, thanks to relativity. If we could achieve and sustain even 1G acceleration, live humans could make the 100LY trip in approx. 9 years (spaceship time). You could leave, visit the planet, and come back only 18 years older and tell the next-next-next-next-next generation all about it. EDIT: To be fair, 1G over 100LY will result in a maximum speed around 0.9998c so I guess you would have to…

Mo' acceleration, mo' trolley problems.

Go on vacation; come back; everyone's dead.

Re: An extrasolar world covered in water?

#55

Post by xwdv »

nekoashide wrote: post #9
Tade0 wrote: post #2

It's around 100 light years away from Earth for anyone interested.

Programming machines to make the trip and then seeding with human life seems to be the best answer to distance.

I doubt this. We seem very hesitant to seed any world with any kind of life, even going through great lengths to ensure no errant bacteria get carried on a rover or something.

If we were serious about spreading life, we could loaded up some rockets with basic organisms and throw them onto whatever worlds we want to seed, and then a few million years of evolution should take care of the rest.

Re: An extrasolar world covered in water?

#56

Post by bil7 »

hypertele-Xii wrote: post #45
freedomben wrote: post #32

Earlier quoted context omitted.

Your question sounds like a troll, but it's actually a fascinating one. Reminds me so much of reading Descartes and essentially asking, "How do I know I'm not asleep and dreaming?"

You know you're awake because reality has continuity and makes sense. Conversely, dreams are fragmented and implausible. You can train yourself to check this to lucid dream (become aware that you are dreaming).

I've had vivid dreams where I was completely convinced I was in reality. Continuity was maintained well enough to fool me. How could I know I wasn't in a dream? How can I truly know beyond doubt that I am not in a dream?

Re: An extrasolar world covered in water?

#57

Post by freedomben »

hypertele-Xii wrote: post #45
freedomben wrote: post #32

Earlier quoted context omitted.

Your question sounds like a troll, but it's actually a fascinating one. Reminds me so much of reading Descartes and essentially asking, "How do I know I'm not asleep and dreaming?"

You know you're awake because reality has continuity and makes sense. Conversely, dreams are fragmented and implausible. You can train yourself to check this to lucid dream (become aware that you are dreaming).

Yes you can sometimes do that (I've lucid dreamed quite a few times before and it's pretty wild), but it's nowhere near 100% reliable. you can get pretty good with practice, but even then it's not a scientific test. It's more of a process of reasoning and gut checking. The human mind can fill in an incredible amount of detail when needed. In one lucid dream I was playing a song on the guitar that I had (as far as I know) never heard before (myself in the dream was inventing the song). I realized I was dreaming before waking up and practiced the song over and over so it was stuck in my head, and then immediately after waking I wrote down the tablature. It ended up being a pretty good song, and (at least so far) I haven't heard anything else like it.

Obviously this is heavy anecdata, but I've never heard a scientific explanation of how to be certain whether or not you're dreaming (or as Descartes describes, being deceived by a demon).

Re: An extrasolar world covered in water?

#59

Post by dreen »

bumby wrote: post #30
whatshisface wrote: post #26

Earlier quoted context omitted.

Fortunately my blender doesn't need an incentive to grind fruit, only a hundred and twenty volts.

Ah, but what makes you confident humans (or any other animal) isn't likewise acting deterministically with just a veiled illusion of free-will and incentive?

From physics point of view, I guess everything is deterministic. But from a human point of view, the question is irrelevant, because we can only experience reality as humans.

Re: An extrasolar world covered in water?

#60

Post by hey_bear »

xwdv wrote: post #53
hey_bear wrote: post #52

Technically second planet covered in liquid water... they clearly forgot about Earth

Earth is not an exoplanet, it is merely a planet.

"merely a planet", it's sad that the thing that gives everything life and beauty and wonder can be so easily dismissed nowadays...
Post reply on HN