The Comet Kohoutek, visible from Earth during the winter of 1973-1974, trails an enormous hydrogen cloud, visible through telescopes. The comet will not return close to Earth for 75,000 years. (Photo by © CORBIS/Corbis via Getty Images)
The Comet Kohoutek, visible from Earth during the winter of 1973-1974, trails an enormous hydrogen cloud, visible through telescopes. The comet will not return close to Earth for 75,000 years. (Photo by © CORBIS/Corbis via Getty Images)
