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A short history of nearly everythingFar from marking the outer edge of the solar system, as those schoolroom maps so cavalierly imply, Pluto is barely one-fifty-thousandth of the way. Of course we have no prospect of such a journey. A trip of 240,000 miles to the Moon still represents a very big undertaking for us. A manned mission to Mars, called for by the first President Bush in a moment of passing giddiness, was quietly dropped when someone worked out that it would cost $450 billion and probably result in the deaths of all the crew (their DNA torn to tatters by high-energy solar particles from which they could not be shielded). Based on what we know now and can reasonably imagine, there is absolutely no prospect that any human being will ever visit the edge of our own solar system-ever. It is just too far. As it is, even with the Hubble telescope, we canБЂ™t see even into the Oort cloud, so we donБЂ™t actually know that it is there. Its existence is probable but entirely hypothetical.[2] About all that can be said with confidence about the Oort cloud is that it starts somewhere beyond Pluto and stretches some two light-years out into the cosmos ...» |
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