4 ms·
We've been able to fly or emit radio signals only for a bit more than 100 years. If there exist any other civilisations and we assume they start independently,
by twawaaay 4y ago
We've been able to fly or emit radio signals only for a bit more than 100 years.
If there exist any other civilisations and we assume they start independently, there should be ones that started billions of years ago. Which is enough to visit entire galaxy even at very slow speeds.
The paradox is that we are not seeing any signs of any other intelligent life.
- credit_guy 4y agoOnly if they are in our own Solar system. But you can easily imagine a supercivilization visiting lots of solar systems, but not establishing permanent colonies everywhere. As I said, what if 5% of the solar systems are teaming with life? That would still be tens of millions of solar systems in our galaxy. The diversity of life could be something to make Star Wars look unimaginative. And we'd have no idea they are out there.
- twawaaay 4y agoWhat kind of argument is this "only if they are in our own solar system"? Even at the speed of Voyager 2, (15km/s), in a billion years it would cover about 4 * 10^17 km or about 40 thousand light years. I am pretty sure people who have been developing for hundreds of millions of years can do better than that, by orders of magnitude. Also you put a totally strange assumption that all civilisations will only restrict themselves to visiting planets. If there is a lot of civilisation it is more likely they will have different motivations.
- Valgrim 4y agoIf the dark forest hypothesis is true, you can bet any civilization advanced enough to detect us will go out of their way to avoid being detected by us. For all we know, there could be a gigantic tungsten rod slowly and purposefully accelerating toward us that would destroy all life on earth in ten thousand years, and we'd have no way of knowing.
- oAlbe 4y agoWhy a tungsten rod in particular?
- legutierr 4y agohttps://en.wikipedia.org/wiki/Kinetic_bombardment https://en.wikipedia.org/wiki/Kinetic_bombardment
- vardump 4y agoPresumably because it's high density and thus higher destructiveness vs detectability? Although I guess they could also just paint their weapon black. A different matter how they hide the engine's infrared signature. Perhaps by just not running it when approaching, except for the final course corrections.
- deleted 4y ago[deleted]
- twawaaay 4y agoI am not sure about usefulness of kinetic impactors at near light speeds over long distances. Imagine you are in impactor frame of reference -- any particle of dust it meets will cause tremendous damage to it regardless of what the impactor is built of (assuming our existing technology). It is in my opinion very likely that over long distances the impactor will just get converted to a shower of high energy particles over very large area.
- vardump 4y agoStars move relative to each other. You won't need much higher speeds than what we can already achieve, as long as you're willing to wait for another star to move nearby.
- vardump 4y agoStars don't have same velocities: https://en.wikipedia.org/wiki/Stellar_kinematics https://en.wikipedia.org/wiki/Stellar_kinematics Gliese 710 is probably going to cross Oort cloud in 1.29M years. Perhaps we should wait and hop to this star? https://en.wikipedia.org/wiki/Gliese_710#Computing_and_details_of_the_closest_approach https://en.wikipedia.org/wiki/Gliese_710#Computing_and_detai...
- thehappypm 4y agoIf they visited us a billion years ago, would we know? Time is as big as space. If you’re positing that aliens must exist and can explore, they might have just done that and lost interest a million years ago, or they do sweeps every hundred thousand years.
- withinboredom 4y agoPlot twist: dinosaurs were really an alien species. After they were wiped out by an asteroid slung at the earth by an evil prince, the earth was written off as a memorial site.