Tempel 1 was discovered in 1867 by Wilhelm Tempel and has since been known to orbit the sun about once every 7 years. The comet’s orbit sometimes brings it very close to Jupiter, however, and the gravitational pull can alter its orbit. Scientists had thought that the comet disintegrated when they couldn't find it for nearly 60 years, but when new calculations were done taking Jupiter’s pull into account, they re-discovered it.