111–120 of 210 posts
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"I think you could live nearly forever and learn far more." But it wouldn't be you living forever. It would be some copy of you (at best).
What’s the difference?
There exists an interesting XKCD comic "Surface Area", about a giant patchwork quilt, comprised of all solid surfaces in the Solar System. To visualize that the combined surface area of all solid bodies (in the Solar System) is surprisingly small.
Earth and Venus had a major share on that quilt, and the combined surface areas of all other planets, dwarf planets, big moons and small moons were surprisingly small.
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The third option is that everything is simply too far apart and any detectible transmissions are either too faint or buried behind all those massive fusion furnaces. For instance, if our best Earth tech was pointed at Earth from a distant star, how far away would we be able to detect our own traces of life? We know that life is "a little rare" at least, but there is a huge range of rarity where life is everywhere acr…
Everything is simply too far apart. That's very likely. There are only two known systems with possibly habitable planets within 40 light years.
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Exactly. For an optimist, we might one day colonize Mars. Next, getting out of our solar system is incredibly unlikely as the first habitable destination in our own galaxy is just so far away. Say we stretch our optimism and do make it. Now the colonization of the Milky Way starts. It's a 100,000 light years to the other end. You'd be a completely different species by the time you arrive. Say you achieve that (you wo…
It's very late and I don't have the energy to look up the math, but: Assuming you're traveling at light speed across the Milky Way, a distance of 100,000 light years, the trip would take 100,000 years for the person traveling, no? I wonder then how long it would be for everyone left on Earth. Millions of years?
The closer you get to light speed, the less time it seems to you to take getting there. If you could get close to light speed, "only" 100,000+ years would pass back home, never less, but could be any larger amount. At 1/10 light speed, a million years pass back home and almost a million on board.
If you don't get really, really close to light speed, it still takes thousands of years, on board.
Getting close takes way, way more energy than (e.g.) getting to half light speed did, which itself takes unimaginably much; getting to 3/4 takes way more than getting to 1/2.
You probably can't carry enough material to produce that much energy, but everything you encounter on the way is blasting you at a good fraction of lightspeed. Maybe a laser from home can keep providing you energy, but that has to keep working for 100,000+ years. The faster you go, the less energy it can provide; and the farther away you are.
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Perhaps the intelligent life is so rare that we're the first species that exist across the universe and we're destined to reach for the stars - unless of course we manage to annihilate ourselves first. But then, if there's nobody else but us then perhaps all what we experience is just an elaborated simulation of more advanced species - perhaps our ancestors, who decided to keep us and our universe as a kind of memoir…
> A future of Star Trek, where the protective veil of some kind of "prime directive" is being lifted as we reach certain level of development as civilisation and then we get a galaxy-wide club membership feels like naive funny fairy tale. It would be of course great if that would happen but it's more likely reality is, or will be way too mundane and unattractive. A story on that topic - The Crystal Spheres by David B…
See also The Dark Forest: > The universe is a dark forest. Every civilization is an armed hunter stalking through the trees like a ghost, gently pushing aside branches that block the path and trying to tread without sound. Even breathing is done with care. The hunter has to be careful, because everywhere in the forest are stealthy hunters like him. If he finds other life—another hunter, an angel or a demon, a delicat…
I always liked this description because it is so similar to the descriptions of untouched cultures in West New Guinea when they were first discovered in the middle of last century. These cultures were entirely untouched and it gave anthropologists a look into what life was like before before civilization. The island was divided into tiny tribes which lead an incredibly brutal way of life. One of the interesting featu…
Either intelligent life is rare in the universe or there's something that happens to it that prevents it from what we envision as the future of our own species, i.e., colonizing and spreading among planets. Maybe 99.99% of species ruin their own climate before getting off-world. Maybe they all decide it's happier living as hunter-gatherers. Unless we're alone, there is some fate that's common to all intelligences and…
Yeah because you know exactly what alien civilization would have done right? Because that's what you would do, as a human. We are talking about aliens and we don't know what they would be like so assuming that they would think like us is just stupid.
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It actually doesn't require THAT much energy to get into orbit. The energy of a kilogram of mass in low earth orbit is about 9 kWh, although rockets will use a bit more than that (not enormously more, though). Fuel cost remains a minor fraction of launch cost, even with Falcon 9. In comparison, the best aluminum plants in the world use 13 kWh to make a kilogram of aluminum. Yet no one says aluminum is out of reach be…
An interesting problem is "how much energy would it take to launch from a super-earth?" https://www.space.com/40375-super-earth-exoplanets-hard-alie... > To launch the equivalent of an Apollo moon mission, a rocket on a super-Earth would need to have a mass of about 440,000 tons (400,000 metric tons), due to fuel requirements, the study said. That's on the order of the mass of the Great Pyramid of Giza in Egypt. We m…
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It actually doesn't require THAT much energy to get into orbit. The energy of a kilogram of mass in low earth orbit is about 9 kWh, although rockets will use a bit more than that (not enormously more, though). Fuel cost remains a minor fraction of launch cost, even with Falcon 9. In comparison, the best aluminum plants in the world use 13 kWh to make a kilogram of aluminum. Yet no one says aluminum is out of reach be…
Aluminium has been out of reach for much of history.
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An interesting problem is "how much energy would it take to launch from a super-earth?" https://www.space.com/40375-super-earth-exoplanets-hard-alie... > To launch the equivalent of an Apollo moon mission, a rocket on a super-Earth would need to have a mass of about 440,000 tons (400,000 metric tons), due to fuel requirements, the study said. That's on the order of the mass of the Great Pyramid of Giza in Egypt. We m…
A super earth would require exponentially more energy with chemical rockets, due to that darn rocket equation. Fortunately, Earth isn't that bad.
Polynomially, right?