A Comet's Brush with the Sun
Fortunately, the NASA/ESA Solar and Heliospheric Observatory has captured the comet's arrival. The spacecraft's Large Angle and Spectrometric Coronagraph, which continuously monitors conditions in the solar corona, picked up the comet in its wide field of view yesterday and has recorded its passage in a remarkable series of images.
When amateur skygazer Don Machholz discovered this comet in May 1986, astronomers initially thought it would make one quick pass through the inner solar system and then disappear forever. But they soon realized that Machholz's find was a periodic comet that orbits the Sun every 5.3 years, traveling in a looping trajectory that extends beyond the orbit of Jupiter. "This is really a remarkable orbit," observes Daniel W. E. Green (Harvard-Smithsonian Center for Astrophysics), in that the comet spirals a little nearer to the Sun at each perihelion then evolves outward over a 4,000-year-long cycle. By the year 2450, should Machholz 1 survive that long, it will pass only 5 million km (0.03 astronomical unit) from the Sun.