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

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

#91

Post by m_mueller »

hyperpallium wrote: post #75
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…

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?

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

#92

Post by lucb1e »

simonh wrote: post #61
hamilyon2 wrote: post #47

Earlier quoted context omitted.

Actually, one could refuel reactive mass by mining those planet if delta v is favorable. Reactive mass deficit is one of biggest problems with interstellar travel. Suddenly, I think interstellar travel is a bit less impossible.

The trouble is you'd need to stop, mine the mass, then accelerate back up again. If you have the fuel to stop to refuel in the first place, you don't need to stop refuel, unless there's something else you need as well.

I think that's what your parent meant with "if the delta v is favorable", like, if you move in the same direction and the speed difference isn't too absurd, it might be worth mining there.

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

#93

Post by sudhirj »

senectus1 wrote: post #2

I wonder what happens to the planets in the solar system when a rogue planets gets sucked into the star (sun) ? I mean, yeah it'd be bad if a rogue planet smashed into us, or even came close enough to mess with our gravitational pool (or the moons). but I imagine if an earth sized or bigger slammed into the sun, that we'd feel the effects of this. massive solar flare roasting our planet alive? a shower of ejecta from…

There's an exploration of that in book 2 of the Three Body Problem / The Dark Forest. Don't remember exact details, but I think it posited the destruction of the inner solar system, mostly due to solar wind both roasting the inner planets, and slowing them down - which causes more planets to fall into the sun in a chain reaction.

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

#94

Post by sudhirj »

cobbzilla wrote: post #88
ben_w wrote: post #69

Earlier quoted context omitted.

The extra mass of the planet would increase the rate of fusion. https://what-if.xkcd.com/14/

to a point you are right, but clearly there is some boundary, right? imagine a solid object with a mass just below the Chandrasekhar limit and a temperature near absolute zero. Don't tell me hurtling that into the Sun will make it burn hotter. And even if it would (or a smaller object) in the long run, there would at least be some period of time before the incoming matter reached fusionable temperatures, reducing pow…

Seems unlikely for fusion. Think of it from the point of view of star formation - the gas that coalesces into a ball is already super cold from floating around in space. The heat for fusion comes from gravity compressing the matter, not from the starting heat energy present in the matter itself.

So yeah, you can't really add cold stuff to starts to extinguish them - stars are made from absolute ice to being with.

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

#95

Post by hyperpallium »

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?

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

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

#96

Post by m_mueller »

hyperpallium wrote: post #95
m_mueller wrote: post #91

Earlier quoted context omitted.

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

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.

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

#97

Post by hyperpallium »

DoctorOetker wrote: post #90
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...

you mean well before the big bang: e^(a*t) = 0 for t=-infinity

well yes; technically they use one base-pair as the origin of life (which is probably still a little too small).

From looking at the graph, and the 300 milion year doubling, they seem to put life complexity at about 256 base-pairs at the origin of the earth.

There should be a link to the actual paper in the article.

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

#98

Post by kamaal »

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?

I think a lot of answers have existed for that question.

In the context of this thread, lets say you are a species which stepped out of your planet, there are plenty of asteroids, and even planets lying around you can mine for resources. You settle billions of your kind in space. You are not running out resources and have no motivation beyond research and science to venture out a little far.

Would you, such a race, want to travel interstellar distances? You would travel far distances by organic growth.

Also its likely how old the universe is anybody who didn't kill themselves to extinction, is likely at our phase of development. And is likely asking the same questions as us. Those beyond our phase of development are hiding for a good reason.

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

#100

Post by coldtea »

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?

Fermi's paradox is just a hand-waving argument involving tons of unknown probabilities.

It's not a given that alien civilizations "should" have developed this or that technology that we ourselves don't have.

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