Future visitors to Neptune and Uranus might want to take along a bucket. Atmospheric conditions on both planets would cause most unusual precipitation - diamonds, which would rain from the sky, according to researchers from the University of California, Berkeley. Both planets have atmospheres with a high methane content and this can be converted directly to diamonds at the high temperatures and pressures found on these planets. Writing in the journal, Science, the researchers described experiments in which they squeezed liquid methane to several hundred thousand Earth atmospheres then blasted it with lasers, heating it to 5,000 Fahrenheit. The result was diamond dust.