RE: When do you think we will have extraterrestrials visit us? visit us
June 8, 2012 at 12:33 pm
(This post was last modified: June 8, 2012 at 12:36 pm by Anomalocaris.)
(June 7, 2012 at 5:21 pm)Welsh cake Wrote: 1. If they had the technology for interstellar travel, how the hell would aliens even know we exist? Our planet is an insignificant pale blue infinitesimal spot in the vast cosmos.
Actually, our planet is extraordinarily conspicuous if you know what to look for. Not many objects are as bright in some of the radio frequency wave lengths we use for communication as our planet. Sharp spikes in radio emission in those frequencies doesn't occur in nature, and would make us stand out like a sore thumb to anyone with technological capability even just a couple decades beyond ours who are interested in looking.
Anyway, we are fairly close to being able to take detailed spectrographs of earth sized planets within a few dozen light years. That means we are within a few years of being able to detect atmospheric evidence both of life roughly similar to ours, as well as evidence of gas emitting industrial processes we can understand.
So within a decade or two, if there was another earth populated by a technological specie similar to ours, we will know.
(June 7, 2012 at 5:21 pm)Welsh cake Wrote: 2. Why the hell would they even care about coming here? If they're all that advanced then I'm fairly confident they'd be smart enough to know this trip isn't exactly what you'd call "necessary" and horribly uneconomical at best. If they're violent, then what's stopping them from invading?
That's a better question. I see no compelling reason why any technologically sophisticated alien must be interested in contacting us. The notion of intelligent aliends wants to "know we are not alone" seems horribly anthropocentric, and in any case, suppose all the aliens capable of visiting us have long ago known perfectly well they are not alone, why visit us in particular?
(June 7, 2012 at 9:37 pm)Cthulhu Dreaming Wrote: I think this is an interesting thought experiment. Given the sheer number of stars, and by extension, planets in the galaxy (much less the universe), it seems probable that life exists elsewhere. How common it is, who knows? That is of course an important unknown variable in Drake's equation.
With the theoretical problems with FTL travel, and the practical issues of subliminal spaceflight, it's probably safe to say that any ET's visiting earth would be far more advanced than we are. Better hope they are benevolent, or that we have nothing they want. As to their possible motivations for visiting, it would likely be the same as ours: curiosity. Were we to detect ET life, would we not want to investigate it?
With all that said, until we gain a greater understanding of the frequency of planets with the capacity to support development of advanced life, the question is highly speculative, if interesting.
A related question that I think is equally interesting: Which is likely to occur first, an earthly visitation by ET life, or human discovery of extant ET life (even if it's microbial)? I think it's probably the latter, possibly even in our own solar system. I hope I live long enough to see us explore that possibility (Europa, for example). I'm not terribly optimistic on that one, considering the state of our space exploration programs, but one can hope.
I also think the number of places in the universe where microbial life have spontaneously arisen would vastly outnumber the places in life where life attain the sort of sophistication required for intelligence. So by sheer chance, we'll find perhaps tens or hundreds or thousands of separate indiginous lineages of primitive life before we find anything so sophisticated as an earth worm.
