4 ms·
Our galaxy is estimated to be at most around 180,000 light years in diameter. Even at a fraction of the speed of light, the amount of time to expand and fill t
by andrewla 10y ago
Our galaxy is estimated to be at most around 180,000 light years in diameter.
Even at a fraction of the speed of light, the amount of time to expand and fill the galaxy is still an eye-blink in geologic time. Even in evolutionary timescales it's still an eye-blink -- the Cretaceous era ended about 66 million years ago.
I think the depressing truth is that we are alone in this galaxy. See [1] for Michael H. Hart's extremely compelling discussion of this idea.
[1] http://adsabs.harvard.edu/full/1975QJRAS..16..128H http://adsabs.harvard.edu/full/1975QJRAS..16..128H