Agreed, but it makes me wonder in a philosophical way... if we are supposed to be. I know it sounds insane, but just read a moment. Humanity, as a whole, reaches for the stars, and we have since time immemorial. Humans, according to NASA, cannot interstellar travel currently without it being a death sentence, and they (NASA) needs astronauts that are genetically predisposed to fight cancer due to the cosmic rays of the universe constantly bombarding the human genome, and mutating it & making malignant cancer. Currently anyone who goes to Mars WILL die of cancer if they make it back to earth. Given that knowledge, and a quick look around the current biosphere I have to wonder if humans are collectively, unconsciously doing this to themselves to increase cancer resistance in preparation for interstellar travel. Then again, I am into my dodgy science. Seriously, just a thought I have been mulling with in the last few weeks because no rational being, from ant to whale would do this to their home, but humans are.