Five Planets Will Clump Together in April, May WASHINGTON (Reuters) - The five so-called naked eye planets -- Mercury, Venus, Mars, Jupiter and Saturn -- will appear to clump together later this month in a sight that might not be seen again for a century. But don't call this a planetary alignment. And even though this is fairly rare, there is nothing for earthlings to worry about, astronomer Geoff Chester of the U.S. Naval Observatory said on Tuesday. The grouping of the five will begin to be visible with unaided eyes around April 20, with the planets clustered closest by around May 4, Chester said by telephone. "It is an opportunity to see all five of the naked eye planets in the same part of the sky at the same time and that does not happen very often," Chester said. It could be 50 or 100 years before this happens again, he said. click for complete article