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

Space Is Full of Planets, and Most of Them Don't Even Have Stars

forbes.com

Post reply on HN
Print view View original

131–140 of 182 posts

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#131

Post by Tepix »

RobertoG wrote: post #119
m_mueller wrote: post #91

Earlier quoted context omitted.

What about Fermi's paradox though? I mean, where is everyone?

A main component of the paradox is time, but this paper solve that. Life existed from the beginning, but only now has become complex enough. So, we don't see or hear artificial signs in other galaxies because light is from the times when there was not complex life in the universe. Now, we only have to solve why we don't see or hear artificial signs in our galaxy. But the problem is not so perplexing because we are ta…

What are the odds that our life is the first that has reached sufficient complexity to be able to communicate within our galaxy? Given that there are 100-400 billion stars (and even more planets) just in the Milky Way: Pretty much zero.

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#132

Post by Aaargh20318 »

pavlov wrote: post #113
Aaargh20318 wrote: post #102

Earlier quoted context omitted.

Personally I think the answer is anti-natalism. Once life gets more intelligent it takes a relatively short time (compared to the age of the universe) to get to the point where they realise it's unethical to create new life and choose to go extinct. As a result, intelligent life around the universe only exists as short 'blips', being around for too short a time to ever meet other species.

The default for unintelligent life is to survive at all cost and fill every niche. You're suggesting that intelligence flips that purpose so that every sentient species eventually becomes depressed suicidal existentialists?

Not depressed or suicidal, just realising they have no right to gamble with another human being's life.

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#133

Post by nkrisc »

itronitron wrote: post #26

Interstellar travel now seems a lot more hazardous than it did before. To quote one of my TAs in college, "it's the stuff you can't see that gets you" ...

It appears we'll need a guild of navigators, of sorts, to guide interstellar craft.

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#134

Post by Murdodc089 »

afterburner wrote: post #29

New 4x games should now include plenty of planets between star systems. Cold and still, but potential mining boons and refueling bases.

I'm sure someone is already working on a mod for Stellaris that does exactly what you describe.

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#135

Post by CodeCube »

Tepix wrote: post #131
RobertoG wrote: post #119

Earlier quoted context omitted.

A main component of the paradox is time, but this paper solve that. Life existed from the beginning, but only now has become complex enough. So, we don't see or hear artificial signs in other galaxies because light is from the times when there was not complex life in the universe. Now, we only have to solve why we don't see or hear artificial signs in our galaxy. But the problem is not so perplexing because we are ta…

What are the odds that our life is the first that has reached sufficient complexity to be able to communicate within our galaxy? Given that there are 100-400 billion stars (and even more planets) just in the Milky Way: Pretty much zero.

I appreciate a good reason to think deeply as much as the next person ... but odds are just that, odds. If we were the result of some freak black swan event that kickstarted "life", the odds of it happening are irrelevant ... because it did.

To be clear, I'm not saying that's what it is ... the fermi paradox is a great thought experiment. But let's just keep things in perspective. Low odds don't mean something won't happen, just like "true random" doesn't mean the same song can't/won't play 10 times in a row ;)

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#137

Post by joshuahedlund »

quietbritishjim wrote: post #77
perl4ever wrote: post #19

Based on the inverse correlation between star size and frequency, this doesn't surprise me at all. It seems like there is an obvious further inference to make - people have debated whether life originated on earth or not. Given that the vast majority of planets do not have a star, and given that we know there are chemotrophs even on Earth that prove it is possible to live without a sun, it seems overwhelmingly likely…

> life appeared so soon after the Earth became solid It took hundreds of millions of years, possibly up to a billion years, for basic life to form on Earth. I would say that is not "soon"; it's a really long time . The obvious response to that is, yes it seems like a long time, but it's not much on geological time scales. But it feels to me that there's an implicit circular argument here: the whole reason that geolog…

> It took hundreds of millions of years, possibly up to a billion years, for basic life to form on Earth.

This is a common popular misconception. See something like Simon Conway Morris's book Life's Solution. There is evidence that life existed on earth almost as soon (geologically speaking) as the early bombardment stopped repeatedly boiling away the entire oceans and atmosphere, within something like 10-20 million years. Thus, all the interpretation about the implications of that.

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#138

Post by joshuahedlund »

throwaway5752 wrote: post #121
zeth___ wrote: post #87

Earlier quoted context omitted.

Life shows up in the fossil record more or less as soon as rocks on the Earths surface start forming. The first billions years on earth mostly involved the planet getting hit by large things and the surface melting. Repeat every millennium.

You just explained why there's no fossil record from early earth, unless I'm misunderstanding you and that was your point. Ocean floor is continuously destroyed as it's subducted, and continents won't have fossils if they are under frequent bombardment.

> continents won't have fossils if they are under frequent bombardment.

Right, but if giant bombardments completely boil away the oceans and atmosphere to rain liquid rocks back down on the surface, there very very likely won't be life, either. So the claim is not just that "fossils only go back to X" but that X is so close to the end of the giant bombardments that there's almost no time left (geologically speaking - maybe 10-20MY) for "life but no fossils yet".

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#139

Post by emiliobumachar »

CodeCube wrote: post #135
Tepix wrote: post #131

Earlier quoted context omitted.

What are the odds that our life is the first that has reached sufficient complexity to be able to communicate within our galaxy? Given that there are 100-400 billion stars (and even more planets) just in the Milky Way: Pretty much zero.

I appreciate a good reason to think deeply as much as the next person ... but odds are just that, odds. If we were the result of some freak black swan event that kickstarted "life", the odds of it happening are irrelevant ... because it did. To be clear, I'm not saying that's what it is ... the fermi paradox is a great thought experiment. But let's just keep things in perspective. Low odds don't mean something won't…

The troubling thing about the Fermi paradox is that the Great Filter may still be ahead of us.

As in, the universe may be littered with the ruins of single-planet civilizations slightly ahead of our technology level. We may have observed and cataloged many such planets, failing to notice the ruins.

Re: Space Is Full of Planets, and Most of Them Don't Even Have Stars

#140

Post by Eesais2e »

antognini wrote: post #16
SubiculumCode wrote: post #15

Earlier quoted context omitted.

Not a physicist. If napkin calculation goes, that's 1000 Jupiters per star. Is that really improbable? There is a lot of space outside of solar system radii.

I think it would require more like 10,000 Jupiters per star to account for dark matter in the Galaxy. The issue is that these microlensing surveys put an upper bound on the number of rogue Jupiters that can be floating around and this bound is much less than 10,000 per star.

Can microlensing account for the whole continuum of black hole sizes that might be floating around in the galactic halo?
Post reply on HN