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Fascinating. Our little rock could be "one in a billion" and we would still have 16 other civilizations to meet. Just in our galaxy.
by jonknee 14y ago
Fascinating. Our little rock could be "one in a billion" and we would still have 16 other civilizations to meet. Just in our galaxy.
- mistercow 14y agoActually we would expect to have 17 other civilizations to meet. The events are independent, so observing our own civilization doesn't affect the odds for the rest of the galaxy.
- marshray 14y agoBut we're not interested in Earth, so we'd expect to see 16.999999999 other civilizations.
- 31reasons 14y agoI am curious How did you get to this number ?
- jonknee 14y agoIf there are 17 billion Earth sized planets out there and we're "one in a billion" that would mean there are 17 planets as perfect as ours that there is life. 17 - 1 = 16. The billion figure was just pulled out of thin air, "one in a X" is a common expression and for this purpose billion seemed appropriate. If we're actually only one in a million, we'll be busy meeting our new friends.
- mistercow 14y ago>If we're actually only one in a million, we'll be busy meeting our new friends. The Milky Way is roughly a disk, so let's think in two dimensions, and for the sake of being reasonable, let's just talk orders of magnitude. The area of the Milky Way disc is on the order of 10^9 square light years. If there are 10^4 civilizations in the Milky Way, that means we should expect one other civilization within a 10^5 square light year neighborhood, meaning that we would expect the nearest civilization to be on the order of 100 light years from us. Over that distance, it would be plausible for two civilizations to transmit information to each other, but "conversations" would take generations. And that's if we ever managed to find them.
- joe_the_user 14y agoIndeed, "one in a billion" might mean that our civilization is the civilization one among among a billion life supporting planets. How does civilization last after it acquires the ability to transmit and receive radio waves? Human certainly seems to be at least threatening portions of earth ecology. Suppose alien ecologies are, on average, more fragile and easily disrupted by the unintended consequences of transformation. Civilizations might exist but be a quite transient phenomena over the galaxy. It is very hard to predict, naturally but interesting to speculate.
- loceng 14y agoOne in a billion, though, what are the odds of life existing? It might be much higher than that. I really don't know much in this area of science though.