10 Facts About The Universe That Make Your Brain Hurt

10. There Could Be Billions Of Alien Civilisations In Our Galaxy

So said Dr Frank Drake at any rate, and we're not talking Star Trek or Analog Science Fiction here. He is the highly respected astronomer and astrophysicist who dreamed up the Drake Equation before a meeting of like-minded scientists and others in 1961. The Drake equation is: N = R* · fp · ne · fl · fi · fc · L where: N = the number of civilisations in our galaxy with which radio-communication might be possible, i.e. which are on our current past light cone; and R* = the average rate of star formation in our galaxy fp = the fraction of those stars that have planets ne = the average number of planets that can potentially support life per star that has planets fl = the fraction of planets that could support life that actually develop life at some point fi = the fraction of planets with life that actually go on to develop intelligent life (civilisations) fc = the fraction of civilisations that develop a technology that releases detectable signs of their existence into space L = the length of time for which such civilisations release detectable signals into space Granted that this is a probabilistic argument and anyone paying attention to it will immediately spot some potential flaws. We do not know of any actual planets aside from Earth that have intelligent life and we are only just beginning to make headway into understanding the fraction of stars in our galaxy that have planets at all, (exoplanets). And to be fair to Dr Drake he did originally think this up to stimulate discussion more than anything else. That said, it does make theoretical sense, which could explain why it continues to be taken seriously. So much so that NASA's Kepler space telescope was until recently dedicated to searching for exoplanets in our region of the Milky Way galaxy. Scientists are currently trawling through masses of data from the Kepler telescope and it appears that roughly one in every five sun-like stars has a potentially habitable, Earth-size planet orbiting it. If we extrapolate from those figures the number of planets that could eventually become 'candidates' as bearers of extra terrestrial life the total runs into billions. Whatever we make of the Drake equation itself the latest findings represent real progress in filling in the gaps in the numbers.