Three-Mile-Wide Asteroid to Fly by Earth One Week Before Christmas

Article Contributed by
Walt Pickut
Martz/Kohl Board of Directors

Planet Earth returns to the celestial shooting gallery.

An asteroid named 3200 Phaethon, not discovered as a Near-Earth Asteroid until 1982, will streak past Earth on Saturday, December 16, missing us by a mere 6.4 million miles, according to NASA. Its proximity labels it a “potentially hazardous” asteroid. While the distance seems large by every-day terms, in astronomical terms that’s a pretty close call.

This object is about the same size as the one that crashed into Earth 65 million years ago in a worldwide catastrophe that changed the Earth forever, sending the dinosaurs and thousands of other species into extinction.

Back yard stargazers and amateur astronomers can expect to see spectacular evidence of 3200 Phaethon’s grazing fly-by this month: the Geminid meteor shower called by many, “The king of the meteor showers.” The waning crescent moon will leave the sky dark for optimal viewing, with the best viewing after midnight.

For reasons scientists do not yet understand, Phaeton is preceded and followed along its orbit by a speeding stream of debris apparently dislodged from its surface. Every year Planet Earth plows through that stream. Chunks of Phaeton streak into Earth’s upper atmosphere at 22 miles per second, nearly 80,000 miles per hour. A piece of space rock no larger than a marble traveling at that speed carries so much energy that it will explode into a streaking fireball bright enough to light up the countryside for a few seconds before it burns away to a glowing and fading streak of smoke 60 miles above the Earth.

The Geminid meteor shower, made up of particles in 3200 Phaeton’s debris stream, is expected to provide as many as 120 to 160 such brilliant, multicolored events – “shooting stars” – every hour, some smaller and possibly a few larger. The asteroid’s debris field is diffuse and extensive, scattered millions of miles all along its orbit through space. As a result, the Geminid meteor shower can be seen annually anywhere between December 7 and 17. This year the peak show is expected to be December 13 to 14, while the asteroid itself follows in its closest approach to Earth 2 days later.

“The best way to watch a meteor shower is with your own eyes,” said Gary Nelson, President of the Martz/Kohl Observatory in Frewsburg and co-owner of Hall & Laury Opticians in Lakewood. “They just move too fast to catch a glimpse with a telescope or binoculars.” Asteroid 3200 Phaeton, however, should be easily visible in even a modest amateur telescope.

Assuming clear skies, observations and measurements on (and around) the night of the 16th at the Martz/Kohl Observatory will be made, along with other observatories around the world, to further refine 3200 Phaeton’s orbit. Such observations help gauge the danger of future close approaches. In 2093, for example, it is slated to fly within 1.8 million miles of Earth.

NOTE to Friends of the Martz/Kohl Observatory. On Wednesday, December 13, the observatory will be closed to the public due to an on-site, annual appreciation program and Christmas Dinner to honor the volunteers and members who have made 2017 a great success. On Thursday, December 14, however, and possibly Saturday, December 16 – the night of closest encounter – if the skies are clear, observatory staff plan to be present, possibly allowing for some public viewing opportunities.

For a deeper look at the night sky, planets, stars and the entire universe, visit the Martz/Kohl Observatory online at martzobservatory.org, check the schedule of events and visit in person. Thank you to Hall and Laury Opticians for sponsoring these Martz/Kohl column.