Comets are rare visitors to Earth. Before modern astronomy, they were often seen as bad omens that heralded war or natural disasters. Even now, a comet is a breathtaking, once-in-a-lifetime event.
Made up of frozen gases and rock, these comic snowballs swing through our part of the solar system during their elliptical orbits. As they pass by the sun, they heat up and shed gas and dust–that’s what forms the distinctive tail.
Were you around when Hale-Bopp appeared in the sky? It appeared on July 23, 1995, and will go down in history as one of the biggest, brightest comets to ever be seen on Earth. Named for Alan Hale and Thomas Bopp, it was so bright that you could see it even in big cities with lots of light pollution. The comet was also unique because of how long it remained visible–just over a year and a half.
If you missed Hale-Bopp, you’ll have to wait 2400 years for it to appear again.
Another comet that passed near Earth in the 90s, Swift-Tuttle originally caused some concern for the possibility that it might hit the Earth or the Moon. Obviously, that did not happen, but it’ll be back every 120 years to give us a thrilling flyby.
The comet was first seen in 1862 by Lewis Swift and Horace Tuttle. Its last visit was in 1992, so we have a long wait until it returns.
The 90s really were the best decade for comets! In 1996, an amateur astronomer named Yuji Hyakutake spotted the comet with a pair of powerful binoculars.
Sadly, this comet has a long orbital period–made even longer because of the gravitational effects of Jupiter and Saturn. Hyakutake won’t appear again for another 100,000 years!
One more comet from the 90s–though one that will never appear in our solar system again. In 1994, Eugene and Carolyn Shoemaker, along with David Levy, discovered a new comet. The reason it’s called Shoemaker-Levy 9 is that this team specialized in finding comets–and they were very good at it.
Shoemaker-Levy 9 was on a crash-course with Jupiter when it was discovered. Astronomers speculate that it was captured by Jupiter’s gravitational field when it passed to close to the massive planet. It broke apart, and the fragments of the comet impacted Jupiter in a spectacular display of cosmic destruction.
The most famous comet is also one of the most frequent visitors to Earth. Halley’s comet–named for the British astronomer Edmund Halley–appears every 75 years. Halley was the first astronomer to figure out that comets were periodic and used older records to predict his comet would return in 1757.
Mark Twain famously arrived and exited this world at the same time as Halley’s Comet–he was born in 1835, and (rightly) predicted that he’d die when the comet returned in 1910. Halley’s Comet is due back in 2061.