But if (by playing with Drake's Equation) one comes to the conclusion that the galaxy has from thousands to millions of civilizations, then what is the likelyhood of *all* of those civilizations following the same path?
Even if just *one* of those "countless" civilizations chooses the path of interstellar colonization, then the whole galaxy would be colonized in, say, a few millions years, even assuming "slow" Orion-type spaceships travelling at 0.1c . "A few millions years" is an eyeblink in cosmic time, so I tend to think that (for some reason yet-to-be discovered) we are the first.
Summarizing: if the orbit of an Earth-sized planet is luckily aligned so that the planet occasionally passes in front of its sun in the viewpoint of someone in Earth, then it will dim the light of its sun in 1/10000. That is very little, but detectable with current instruments. And it is the working principle behind the upcoming Kepler Mission:
http://www.kepler.arc.nasa.gov/
Actually, AFAIR this "Making other Earths" article, they do mention the Kepler Mission... But I am not in the mood to read it *again* in order to check.
I think that one could land fully automated space telescopes (or "telescope kits" to be assembled by robots) anywhere in the Moon without having to use humans, so I am skeptic about such a project leading to the colonization of the Moon.
In fact, it is very hard to think of anything that could lead to the colonization of the Moon (even a hypothetical mining of Helium-3 could be done in an automated way). Perhaps the only possible scenario for Moon colonization is related to Space Tourism: supposing that space flight becomes cheaper and Space Tourism takes off, the Moon would eventually become a tourist hot spot - and newwed tourists going there would add a new meaning to the word "honey moon".:-)
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Even if just *one* of those "countless" civilizations chooses the path of interstellar colonization, then the whole galaxy would be colonized in, say, a few millions years, even assuming "slow" Orion-type spaceships travelling at 0.1c . "A few millions years" is an eyeblink in cosmic time, so I tend to think that (for some reason yet-to-be discovered) we are the first.
Summarizing: if the orbit of an Earth-sized planet is luckily aligned so that the planet occasionally passes in front of its sun in the viewpoint of someone in Earth, then it will dim the light of its sun in 1/10000. That is very little, but detectable with current instruments. And it is the working principle behind the upcoming Kepler Mission:
- http://www.kepler.arc.nasa.gov/
Actually, AFAIR this "Making other Earths" article, they do mention the Kepler Mission... But I am not in the mood to read it *again* in order to check.I think that one could land fully automated space telescopes (or "telescope kits" to be assembled by robots) anywhere in the Moon without having to use humans, so I am skeptic about such a project leading to the colonization of the Moon. In fact, it is very hard to think of anything that could lead to the colonization of the Moon (even a hypothetical mining of Helium-3 could be done in an automated way). Perhaps the only possible scenario for Moon colonization is related to Space Tourism: supposing that space flight becomes cheaper and Space Tourism takes off, the Moon would eventually become a tourist hot spot - and newwed tourists going there would add a new meaning to the word "honey moon". :-)