Space Is Full of Planets, and Most of Them Don't Even Have Stars • Hacker News Board

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

#101

Post by kamaal » Wed, May 30, 2018, 10:19 AM UTC

quietbritishjim wrote: post #84

neuronic wrote: post #82

Earlier quoted context omitted.

But that's mostly because humans aren't an achievement of "life". We were never a development goal of "life" nor does the universe care very much about us - even if we built megastructures directly harnessing the energy of black holes and stars. If current knowledge is remotely correct, heat death will happen, no matter how immortal Homo deus will become. The quarks are against us. And if complex systems theory teach…

Humans are really just an example, I regret mentioning it. All significant developments in life (e.g. multi-cellular lifeforms, post-Cumbrian explosian animals) took hundreds of millions to billions of years.

In fact given the fact evolution is a process without a goal. Intelligence could be even more rare among multicellular lifeforms.

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

#102

Post by Aaargh20318 » Wed, May 30, 2018, 10:26 AM UTC

m_mueller wrote: post #91

hyperpallium wrote: post #75

Earlier quoted context omitted.

If you're a fan of Moore's Law and the Singularity, you'll love the reasoning of backtrapolating the exponentially increasing complexity of life over time... to get 0 well before the formation of the earth https://www.technologyreview.com/s/513781/moores-law-and-the...

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

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.

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

#103

Post by brazzy » Wed, May 30, 2018, 10:31 AM UTC

sundvor wrote: post #79

brazzy wrote: post #56

Earlier quoted context omitted.

Quite the opposite, actually. At near lightspeed, a pea-sized rock will kill your spaceship just as dead as a planet. So you actually want your interstellar masses to be as concentrated as possible.

That's assuming we haven't figured out effective shielding by the time we have those near light speed engines.

Doesn't really make any difference. There is some size of rock that's too big for your shielding, and you rather want that mass concentrated in a handful of planets than spread around.

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

#104

Post by captn3m0 » Wed, May 30, 2018, 10:32 AM UTC

zaarn wrote: post #58

everdev wrote: post #46

Earlier quoted context omitted.

Well, if there's not much around it, it might be hard to detect it's gravitational effects. I'd imagine you could detect it blocking a circular patch of sky more easily and from farther off than you could detect the gravitational pull on your spacecraft. Just don't steer twords the black disc and you'll be fine.

I think not steering towards the black disc is a good advice for space travel in general...

But you can use it for gravitational slingshots.

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

#105

Post by lmm » Wed, May 30, 2018, 10:57 AM UTC

Has the IAU come around to a sensible definition of "planet", or are these officially non-planets?

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

#106

Post by swebs » Wed, May 30, 2018, 11:09 AM UTC

pferde wrote: post #83

ataturk wrote: post #13

Why would we visit forbes.com to learn about astronomy?

We would not, because with javascript disabled, it only displays blank page. :)

Same. Here's an archive:

http://archive.li/TUHro

It would be great if HN had an auto-archive feature now that more people are becoming privacy conscious.

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

#107

Post by gambiting » Wed, May 30, 2018, 11:12 AM UTC

havemylife wrote: post #40

toong wrote: post #28

Earlier quoted context omitted.

Earth needed ~ 2 billion years for life to start. Frequent solar winds - especially in the first few billion turbulent years of the universe - basically sterilize planets and the whole 2-billion-year counter gets reset to 0. Planets that exist without a solar system, but do retain sufficient heat, might have been out of solar winds harm ?

I'm by no means well informed on these topics, but I'm unsure where you're getting your 2 billion year estimate. Furthermore I thought that Earths magnetic field shielded from solar radiation, and additionally that there's a significant amount of radiation in space anyways. Further questioning I have though is, does solar radiation penetrate through ocean water? What radiation is between solar systems or what rogue p…

>>Further questioning I have though is, does solar radiation penetrate through ocean water?

Barely. 10km of water will shield you from almost any amount of radiation, and we know of life forms which live at those depths, so they could have developed even when Earth was completely bathed in radiation.

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

#108

Post by nabla9 » Wed, May 30, 2018, 11:16 AM UTC

boznz wrote: post #59

mrarjen wrote: post #53

Earlier quoted context omitted.

Exactly, and I saw that when the Andromeda Galaxy collides with ours, it's unlikely many planets/systems will be colliding with one another.

Never really understood how galaxies can collide if space has been expanding since the big bang and everything is moving apart

Metric expansion of space has effect only on very large scale. Galaxy clusters have enough gravitational force to keep them together.

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

#109

Post by hyperpallium » Wed, May 30, 2018, 11:20 AM UTC

m_mueller wrote: post #96

hyperpallium wrote: post #95

Earlier quoted context omitted.

It's addressed in the article: it takes a long time for complex life to arise, so we are among - or the - first.

That's the optimistic interpretation. Pessimistic: There's one or more great filters.

No. Assuming this specific paper's thesis, that is the conclusion. There exist other arguments not based on this specific paper's thesis.

Of those, I find plausible the observation that as we tame the world to suit us, we shrink. Cities, civilization, supermarkets, products, TV, internet. By this trend, we'll live in dream terranes before long. (BTW as people get richer, reproduction gets less).

But we'll need power, and eventually a dyson sphere to capture all the sun's light - perfect for an inward-looking, closed-off people! Then what, I'm not sure. Perhaps long before that, we won't need other suns; we'll have artificial suns (controlled fusion).

That's what happens to everyone else: as they grow in technological sophistication, they get better and better at directly meeting their own (previously evolved) needs.

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

#110

Post by tekkk » Wed, May 30, 2018, 11:21 AM UTC

mhandley wrote: post #81

bencollier49 wrote: post #45

Earlier quoted context omitted.

Yes, but it's probably rubbish clickbait. They locked me out of the site when I opted out of tracking. Good riddance and I look forward to their receiving a hefty fine from the EU for GDPR non-compliance.

Yes, I had the same issue. Selected just the minimal cookies they said they needed to run the site. Site makes you way several minutes while the "process your request". Then got locked out. Oh well, another site I can live without, but I too look forward to them getting a fine from the EU.

Yup just ridiculous. Opting out of targeted advertising doesn't mean you can't show ads. Dumbest thing really, how much more money they were going to make if I consented to ad tracking? A percent of a cent?