10

A couple of issues with the Fermi paradox: The Fermi paradox is closely tied to the Drake equation. This equation is the best method we currently have for thinking about the probability of intelligent life in our galaxy. The problem is that there are so many assumptions you have to make in that equation, that the results vary drastically. If you plug some ...


8

I don't see how it could possibly be the cause--it would make interstellar travel harder, it wouldn't make it impossible and it wouldn't destroy the species--once they found out about it they could beef up the defenses of their starships.


6

It is actually the Drake Equation that applies best to this. The Fermi Paradox framed the issue, the Drake Equation tries to wrestle it into an analyzable framework. This io9 article gives an idea of what we are facing when we try to narrow down the possibilities here. It is an extremely compelling matter for which we have no data points. We don't even ...


5

A broader distribution of probabilities would increase the probability that a values much higher as well as much lower than the most likely value are also possible. But is that all that's going on here, or does their new evaluation of the Drake Equation also include a shift downward in the overall expected results? Both. They (properly) point out that ...


5

I think the answer to your question is "yes". The combination of "space is big" and "humans haven't been around long" is a valid (as opposed to good) explanation for the Fermi paradox. I replaced "good" with "valid" because "good" is subjective and can be colored by one's own opinions, and desires, about the possibility of alien life. But as logical ...


4

If anyone anywhere anytime did space travel, they should have been here by now. The Milky Way is small compared to its age and travel times. The Sun has made about twenty orbits around it. The dinosaurs actually lived on Earth when it was on the other side of the galaxy. Either we are alone as a space faring society, or we have company very close by. The ...


3

Interstellar travel isn't the issue — stars are close together and even at 10%c the Milky Way could be traversed safely in 10M years. 10M years isn't a factor. Even if it's 100x slower at 0.1%c, 1bn years to colonize an 11 or 12bn year old galaxy with 6-10bn year old metallic stars (thought to be required for life) isn't a strong filter. If a filter ...


3

Just to say a little more about the "conditioned credence" section, what they are saying there is that the Drake Equation isn't the only data we have. We have also looked for signs of civilization, and there are other ways we might in the future look for civilization. And the fact that we haven't found any evidence tells us something. A concrete example ...


2

The first thing I notice is that the paper first handwaves away the difference between the size of the probe and the size of the replicator. It references the Freitas paper (which is itself pretty handwavey) while failing to mention that the probe required to send the 500t replicator masses ten million tons. The second thing I notice is that the author ...


2

We can do an estimate, but there are going to be pretty big error bars on that estimate. Kepler has given us a lot of exoplanets, but its results are biased: it's easier to detect large planets in small orbits than it is to detect small planets in large orbits. Most of Kepler's results is gas giants. We only have one solar system which we've observed ...


2

I think you have to extend that a bit, to "(Technological) humans haven't been around long, and on present evidence aren't going to be around all that much longer". If the average lifespan of a technological civilization, from the point at which it can produce radio waves (or other emissions) that could conceivably be detected from another star to the point ...


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