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“We’ve been looking for alien life for so long now and the idea that it could turn out to be on our front doorstep, in the very next star system, is piling impr

“We’ve been looking for alien life for so long now and the idea that it could turn out to be on our front doorstep, in the very next star system, is piling improbabilities upon improbabilities. “If there is intelligent life there, it would almost certainly have spread much more widely across the galaxy. The chances of the only two civilisations in the entire galaxy happening to be neighbours, among 400bn stars, absolutely stretches the bounds of rationality.” If there are 2 alien civilisations in our galaxy surely it's equally likely they are next to each other or some arbitrary distance.

FriendlyNormie 6y ago
You just won the retard award.
happytoexplain 6y ago
For each given distance, yes, but the property that's interesting to humans is binary: "near" vs "far". It's also subjective, but almost any definition would put most of the galaxy in the "far" category, thereby making it more likely that a random location is "far".
- usgroup 6y ago
  I’m actually not sure that’s what he meant. I think he meant that if you picked two planets to have life on them at random, and the pairwise distances between planets forms a uniform distribution, then the distance between the two planets randomly chosen is equally likely to be any distance.
Bootvis 6y ago
No, because the volume of the ball around earth grows with distance cubed. Assuming of course that searching in a bigger space is likely to find more non-earth life.
kordlessagain 6y ago
> The chances of the only two civilisations in the entire galaxy happening to be neighbours, among 400bn stars, absolutely stretches the bounds of rationality. I think this is dependent on the conditions by which one or more related lifeforms emerged. It's entirely possible life here came from there or from there to here and the reason it's here and there is because it's close. Chances assuming no travel between the two places is just silly.
zw123456 6y ago
Yes, probably, but then on the other hand, if panspermia (https://en.wikipedia.org/wiki/Panspermia https://en.wikipedia.org/wiki/Panspermia) was the cause of life here, whatever mechanism was at work (e.g. interstellar objects, fragments from an exploded system) then it would make sense to have seeded clusters of stars. Fun to think about, obviously, who knows.
teraflop 6y ago
This is not true even in an extremely idealized model. For example, if you pick two random points in a unit cube, they are much more likely to be a moderate distance apart (on average, about 0.66 units) than they are to be very close together. https://people.kth.se/~johanph/habc.pdf https://people.kth.se/~johanph/habc.pdf
pmoriarty 6y ago
But isn't it easier to detect nearby signals from ones of equal power from further away? If so, why should we be surprised that we detect those signals which are easier to detect before those which are more difficult to detect?

FriendlyNormie 6y ago

You just won the retard award.

happytoexplain 6y ago

For each given distance, yes, but the property that's interesting to humans is binary: "near" vs "far". It's also subjective, but almost any definition would put most of the galaxy in the "far" category, thereby making it more likely that a random location is "far".

usgroup 6y ago
I’m actually not sure that’s what he meant. I think he meant that if you picked two planets to have life on them at random, and the pairwise distances between planets forms a uniform distribution, then the distance between the two planets randomly chosen is equally likely to be any distance.

Bootvis 6y ago

No, because the volume of the ball around earth grows with distance cubed. Assuming of course that searching in a bigger space is likely to find more non-earth life.

kordlessagain 6y ago

> The chances of the only two civilisations in the entire galaxy happening to be neighbours, among 400bn stars, absolutely stretches the bounds of rationality. I think this is dependent on the conditions by which one or more related lifeforms emerged. It's entirely possible life here came from there or from there to here and the reason it's here and there is because it's close. Chances assuming no travel between the two places is just silly.

zw123456 6y ago

Yes, probably, but then on the other hand, if panspermia (https://en.wikipedia.org/wiki/Panspermia https://en.wikipedia.org/wiki/Panspermia) was the cause of life here, whatever mechanism was at work (e.g. interstellar objects, fragments from an exploded system) then it would make sense to have seeded clusters of stars. Fun to think about, obviously, who knows.

teraflop 6y ago

This is not true even in an extremely idealized model. For example, if you pick two random points in a unit cube, they are much more likely to be a moderate distance apart (on average, about 0.66 units) than they are to be very close together. https://people.kth.se/~johanph/habc.pdf https://people.kth.se/~johanph/habc.pdf

pmoriarty 6y ago

But isn't it easier to detect nearby signals from ones of equal power from further away? If so, why should we be surprised that we detect those signals which are easier to detect before those which are more difficult to detect?