Erratically dashing around the Solar System in highly elliptical orbits is the Sun’s family of comets—small bodies made up of frozen debris and gas. Some are very regular in their orbital habits, like Halley’s, which comes hurtling toward the Sun every 76 years exactly; others appear and then disappear for centuries, traveling far beyond the limits of the Solar system. The tails, often millions of miles long, which the Solar Wind causes the larger comets to develop, make them a spectacular sight. In ancient days comets were considered the harbingers of coming disaster.

Courtesy Calvin J. Hamilton, www.solarviews.com