As a comet named 332P/Ikeya-Murakami (aka Comet 332P) was approaching the sun earlier this year, it began to disintegrate. Nothing new about that; comets are fragile, icy bodies that sometimes don’t survive their passages near the sun. But the animation at the top of this page is new, made possible by Hubble Space Telescope observations acquired as the comet was disintegrating. Astronomers say these images provide one of the sharpest, most detailed observations yet of a comet breaking apart. The break-up took place some 67 million miles (100 million km) from Earth, slightly beyond the orbit of Mars, and Hubble was able to capture images over three-day span in January 2016. The images revealed 25 building-size blocks made of a mixture of ice and dust drifting away from the comet at a leisurely pace, about the walking speed of an adult. A NASA statement said:
The observations suggest that the roughly 4.5-billion-year-old comet … may be spinning so fast that material is ejected from its surface. The resulting debris is now scattered along a 3,000-mile-long trail, larger than the width of the continental U.S.
The results are published in the September 15, 2016, issue of The Astrophysical Journal Letters, a peer-reviewed journal.
Lead researcher David Jewitt of the University of California at Los Angeles said in the NASA statement:
We know that comets sometimes disintegrate, but we don’t know much about why or how they come apart. The trouble is that it happens quickly and without warning, and so we don’t have much chance to get useful data. With Hubble’s fantastic resolution, not only do we see really tiny, faint bits of the comet, but we can watch them change from day to day. And that has allowed us to make the best measurements ever obtained on such an object.
The three-day observations reveal that the comet shards brighten and dim as icy patches on their surfaces rotate into and out of sunlight. Their shapes change, too, as they break apart.
The icy relics comprise about 4 percent of the parent comet and range in size from roughly 65 feet wide to 200 feet wide (about 20 to 60 meters wide). They are moving away from each other at a few miles per hour.
Astronomers say these observations provide insights into the volatile behavior of comets as they approach the sun and begin to vaporize.
Comet 332P was 150 million miles (240 million km) from the sun when Hubble spotted the breakup.
Bottom line: Images over a three-day period of a disintegrating comet, from the Hubble Space Telescope. The comet is 332P/Ikeya-Murakami (aka Comet 332P).
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.