10. Alien Invasion

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Yeah, we admit this one is somewhat tongue-in-cheek and is also probably the least likely scenario of all, but it’s a fascinating subject, and many of us do wonder from time to time whether we are alone in the universe. It is estimated that there are at least 100 billion stars in the Milky Way Galaxy alone and some estimates put that number closer to 400 billion. Astronomers estimate that there also may be some 40 billion Earth-sized planets orbiting in the “habitable zones” around stars much like our sun. Now if that doesn’t make your brain hurt, consider that recent estimates indicate that there may be as many as 100 billion galaxies in the universe and if each galaxy contained 100 billion stars as astronomers believe, that means there could be some 10,000,000,000,000,000,000,000 stars in the universe. That number, if we are not mistaken is expressed as 10 to the 22nd power. With all that real estate out there, could we really be alone?