How much does the job pay? http://xnxx.in.net/ xnxx tube The team believe that a catastrophic event must have torn the atmosphere apart 4bn years ago. The clues to this come in the ratio of two forms of the gas argon (one a primitive form, the other created more recently by radioactive decay) which is very different from that on Earth, suggesting that a major upheaval changed their relative amounts. Grady suggests that this could have been due to volcanic eruptions, or a massive collision that stripped the atmosphere away.