Comets usually spin in the same direction as they travel through space. But one Jupiter-family comet, 41P/Tuttle-Giacobini-Kresak, behaved differently. In 2017, as it approached the sun, its rotation slowed dramatically. Its day stretched from about 20 hours to nearly two days. Scientists believe the comet may have briefly stopped spinning before reversing direction.
Astronomers cannot directly measure a comet’s rotation, so they study changes in its brightness. As 41P rotates, sunlight reflects differently off its surface, creating a repeating pattern of light and dark. In the spring of 2017, Neil Gehrels Swift Observatory tracked this pattern and detected the unprecedented slowdown.
By late May, the comet moved too close to the sun in Earth’s sky to be observed clearly. When it became visible again in December, the Hubble Space Telescope captured new images. Later analysis by UCLA astronomer David Jewitt revealed the comet spinning much faster, completing one rotation in about 14 hours. The most likely explanation is that sometime between May and December, the comet’s spin slowed to zero and then restarted in the opposite direction.
The discovery highlights the fragility of small comets. Uneven jets of gas and dust erupt from their surfaces as sunlight heats the ice. These jets act like tiny thrusters, pushing and twisting the comet’s nucleus. If the force becomes too strong, the comet can spin faster and faster until it cracks or breaks apart.
Scientists suspect this process may explain why fewer small comets are observed than expected. Many may gradually destroy themselves through rapid rotation.
The comet will pass near the sun again in early 2028. With new sky surveys expanding, astronomers hope to observe more comets as their spins begin to change dramatically.
May For The Teen Times teen/1774255567/1613367687
1. Which comet reversed its rotation direction?
2. How do astronomers measure comet rotation indirectly?
3. Which telescope later observed the comet again?
4. What natural forces can change a comet’s spin?
1. Why are comets important for understanding space?
2. Would you enjoy studying astronomy professionally?
3. How can new technology improve space research?
4. What space discovery fascinates you most?
Comets usually spin in the same direction as they travel through space. But one Jupiter-family comet, 41P/Tuttle-Giacobini-Kresak, behaved differently. In 2017, as it approached the sun, its rotation slowed dramatically. Its day stretched from about 20 hours to nearly two days. Scientists believe the comet may have briefly stopped spinning before reversing direction.
