Why is that? I've always wondered why the idea of other life outside the Earth seems so impossible for many people on our planet. I mean, our Galaxy, The Milky Way, is home to 200 to 400 billion stars and spans roughly 100,000 light-years from one edge to the other. That's just OUR GALAXY. In 1999 the Hubble Space Telescope estimated that there were 125 billion galaxies in the universe, and recently with the new camera HST has observed 3,000 visible galaxies, which is twice as much as they observed before with the old camera. That's a lot of stars and planets when you break it all down, and if you ask me, the probability that we are alone in the Universe seems pretty absurd.
The idea that there may be life on other planets is widely debated amongst scientists and other groups (specifically religous groups). Earth appears to be a rare planet, able to sustain life and maintain water for long periods of time. The Earth is 3.8 billion years old and intellegent life only occured a little over a million years ago. The placement of our planet is also a key to why life has been able to grow in abundance. We are protected for the most part from astaroid bombardment (thanks to Jupiter) and the placement from our sun makes for habitable water and weather patterns. The Earth may be a rarity among planets. Possibly one in a million or one in a billion, but still, even with that number, it's estimated that in our galaxy alone there may be 10 billion habitible planets.
The same laws that govern the physics that created the Earth, also govern the Universe, so why is our planet so special? Recently, stardust was found to contain amino acids, the building blocks of life. The Earth has numerous extremophiles (organisims that thrive in extream places), which shows us that life can thrive in some really nasty places. Which leads to the questions of evolution, adaptation, and life variation.
We may never know the answer to the question of life on other planets. At least not in my life time, and probably not my son's. Space is a huge place, and unfortunatly, we don't put a lot of effort into studying it (we're to busy building stuff that destroys and kills each other). Personally, I doubt we are the only creatures in the Universe.
Posted by Zoso at January 18, 2005 06:56 AM