11–20 of 114 posts
This seems like a variant of a hypothesis I've heard before: "The universe is old enough, and the rate of expansion of a spacefaring civilization is fast enough (relative to the age of the universe, even at sub-light speeds) that either the aliens should already be here since long ago, or we're the first (or among the first)." ?
It assumes that technology will get to the point where it becomes trivial to explore space. That's not an easy assumption to grant.
Even in case #3, is it reasonable to assume that the aliens would expand in 3 dimensions at the speed of light? And even of that is true, wouldn't we expect a significant fuzziness in that on the order of a millenium, where we see signs but haven't yet been engulfed?
But millions of years of technological evolution is plenty enough time to make grey goo (or light speed spheres of incoming civilization).
This seems like a variant of a hypothesis I've heard before: "The universe is old enough, and the rate of expansion of a spacefaring civilization is fast enough (relative to the age of the universe, even at sub-light speeds) that either the aliens should already be here since long ago, or we're the first (or among the first)." ?
Fermi's paradox. It assumes that technology will get to the point where it becomes trivial to explore space. That's not an easy assumption to grant.
This seems like a variant of a hypothesis I've heard before: "The universe is old enough, and the rate of expansion of a spacefaring civilization is fast enough (relative to the age of the universe, even at sub-light speeds) that either the aliens should already be here since long ago, or we're the first (or among the first)." ?
Of course, here I'm trying to think like an alien civilization that is far ahead from us in technology and scientific knowledge, besides having an alien way of thinking, but the same goes for the article.
In any case, if that is like any disaster spreading through the universe at the speed of light (big rip?) not only we won't have time to notice, we won't be able to feel the effects neither.
1. There is energy to get to speed
2. Mass of fuel to decelerate (and you have to accelerate that fuel in the beginning!)
3. Highly blue shifted CMB (that alone limits how close to c you can get before becoming plasma)
4. Collision with micrometeorites (so the “ship” has to be microscopic or probability of collision quickly goes to 1, and there is no way to survive even micro collisions while moving at c).
5. Limits on how fast you can give impulse (because your ship is made of matter with finite strength). Eg You cant reasonably railgun something to close to c without converting it to plasma.
There is also all the things you do when you get somewhere before sending more probes to expand, presumably it’s not a single location that seeds everything else (and if it is then the energy budget of that is also complicated).
Now, even at 0.1 c and with many pauses to replicate on the new worlds it would still take only a few million years to span the milky way, but if someone was mid-expansion we would see them way before the bubble hits. Being limited to 0.1c also means that those not in our galaxy will likely be unable to expand into ours (and vice versa).
This seems like a variant of a hypothesis I've heard before: "The universe is old enough, and the rate of expansion of a spacefaring civilization is fast enough (relative to the age of the universe, even at sub-light speeds) that either the aliens should already be here since long ago, or we're the first (or among the first)." ?
Fermi's paradox. It assumes that technology will get to the point where it becomes trivial to explore space. That's not an easy assumption to grant.
On the timescale of the universe, geometric growth in colonization is functionally hyper rapid.
So either colonization (and thus, geometric growth) is impossible or there's nobody else out there.