3 ms·

The farther we look, the earlier back in time we see whatever we look at. There is good reason to think that the rise in complexity of organisms is a global fea

The farther we look, the earlier back in time we see whatever we look at. There is good reason to think that the rise in complexity of organisms is a global feature of the universe, so other intelligent life may simply not have developed early enough that we've had time for the light from them to reach us yet.

joshuahedlund 9y ago
I highly recommend Stephen Webb's book Where Is Everybody? on the pros and cons of these arguments about the Fermi paradox. For example, your point is reasonable regarding the overall scale of the universe and life in other galaxies. Yet if life naturally arose on our planet in a relatively short habitable window (<100MM), considering the number of other potential habitable planets in our own galaxy alone, many scientists find it unreasonable to think that we would be the first or only life (and/or intelligent life, depending on assumptions) in our galaxy, within however many billions of years we are into a habitable universal time window. There are fairly conservative calculations that argue we should at least have seen evidence or been visited by at least one civilization trying to escape threats to its own planet within our own galaxy.
jerf 9y ago
Life on Earth is about 3.5 billion years old. If some other species in the Milky Way had beaten us to intelligence by 1%, even assuming they didn't start out another billion or two earlier, that would give them 35 million years to spread exponentially through our 100,000 light-year-wide galaxy. It is possible we are first. The Copernican principle, to my eyes, is taking a bit of a beating lately anyhow. It was a fine heuristic for a while, but many people seem to have forgotten it is only a heuristic that seemed to work for a while and not an actual law of the universe. So maybe we are that unique. But it is worth pointing out that would itself be a significant sea change in the current philosophy dominant in science.
- ptrincr 9y ago
  It's possible that whilst the universe is full of life, intelligent life is quite scarce. It could be we are the first in this Galaxy. It could be that others have come and gone but never quite made it to space. Cave paintings go back 40,000 years. I'd say that displays a level of intelligence. Yet there was a significant period of time until we managed to develop agriculture (30,000 years), or writing (37,000 years). At lot can happen during that time. In fact during these years humans could have died out many times, succumbed to the changing climate or disease. But considering all this, you have to take into account that the universe consists of upwards of 2 trillion galaxies, at least as far as we can see. That's a lot of potential. But if we can never make contact, does it even matter if its there or not?

joshuahedlund 9y ago

I highly recommend Stephen Webb's book Where Is Everybody? on the pros and cons of these arguments about the Fermi paradox. For example, your point is reasonable regarding the overall scale of the universe and life in other galaxies. Yet if life naturally arose on our planet in a relatively short habitable window (<100MM), considering the number of other potential habitable planets in our own galaxy alone, many scientists find it unreasonable to think that we would be the first or only life (and/or intelligent life, depending on assumptions) in our galaxy, within however many billions of years we are into a habitable universal time window. There are fairly conservative calculations that argue we should at least have seen evidence or been visited by at least one civilization trying to escape threats to its own planet within our own galaxy.

jerf 9y ago

Life on Earth is about 3.5 billion years old. If some other species in the Milky Way had beaten us to intelligence by 1%, even assuming they didn't start out another billion or two earlier, that would give them 35 million years to spread exponentially through our 100,000 light-year-wide galaxy. It is possible we are first. The Copernican principle, to my eyes, is taking a bit of a beating lately anyhow. It was a fine heuristic for a while, but many people seem to have forgotten it is only a heuristic that seemed to work for a while and not an actual law of the universe. So maybe we are that unique. But it is worth pointing out that would itself be a significant sea change in the current philosophy dominant in science.

ptrincr 9y ago
It's possible that whilst the universe is full of life, intelligent life is quite scarce. It could be we are the first in this Galaxy. It could be that others have come and gone but never quite made it to space. Cave paintings go back 40,000 years. I'd say that displays a level of intelligence. Yet there was a significant period of time until we managed to develop agriculture (30,000 years), or writing (37,000 years). At lot can happen during that time. In fact during these years humans could have died out many times, succumbed to the changing climate or disease. But considering all this, you have to take into account that the universe consists of upwards of 2 trillion galaxies, at least as far as we can see. That's a lot of potential. But if we can never make contact, does it even matter if its there or not?