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In reply to the discussion: UFOs explained [View all]PoindexterOglethorpe
(25,851 posts)I am constantly amazed at the assumption that just because the universe is so old that technological civilizations must have evolved and so there surely are many advanced civilizations out there.
My Son The Astronomer tells me that astronomers actually think we may be the very first technological civilization in the galaxy.
You need to understand something about star formation and evolution, as well as think hard about how unique the conditions have been on this planet that eventually led to us.
The first stars to form, called Population III stars, were made of helium and hydrogen. They were massive and didn't live very long and when they died, they created some of the other elements. Meanwhile, Population II stars started forming, and they contained more elements. Big improvement in the potential for the development of life. Finally, Population I stars started forming. Our sun is a Population I star. They contain all of the elements needed to seed life.
Our sun is a G type star, also known as a main sequence star. Only about 7 or 8 percent of all the stars in our galaxy are this type. Meanwhile, about 70% of the stars in our galaxy are red dwarfs. If life were to evolve on a planet of a red dwarf, it's going to be very, very different from life on this planet.
It matters a lot that we have our relatively large moon, which creates tides in our oceans, and a lot of those who know more than I do believe that those tides were crucial in allowing life to form. Oh, and the moon also stabilizes Earth's wobble, which means a lot.
I can also think of life evolving in circumstances where they never develop technology, or never are interested in leaving their home planet. What if their eyesight just doesn't allow them to see stars? What if their planet is covered in clouds, so they never see stars? What if their religious beliefs get in the way? Lots of possibilities.
But most important, is that interstellar travel is probably impossible. And don't just blithely assume some species out there is thousands or even millions (a truly ludicrous assumption) years more advanced than we are. Overcoming the speed of light isn't going to happen. And don't say Worm Holes because you'll die just getting into one. Plus, radiation out there in space gets worse the farther you get from our planet, and even more so once you might get outside the solar system. There certainly is a possibility that some amazing new technology could develop a very light-weight shielding of some kind, allow safe travel at least within our solar system. That's realistic, but not guaranteed.
For a lot more information, expressed far better than I have, please do read How To Die In Space by Paul M. Sutter who is an actual astrophysicist.