Hubble Watches Comet Reverse Its Spin Direction

Scientists just witnessed something never seen before: a comet that hit the brakes on its rotation and then started spinning backward.

The Hubble Space Telescope caught Comet 41P pulling off this cosmic U-turn during its 2017 approach to the sun. When the comet first passed close to our star in March, it was spinning at a healthy clip, rotating once every 20 hours or so.

But by May, something strange was happening. The comet had slowed dramatically, taking 46 to 60 hours to complete one rotation. That's three times slower in just two months.

Then came the real surprise. By December, the comet wasn't just spinning again. It had reversed direction entirely and was whirling the other way, completing a full rotation every 14 hours.

David Jewitt, a planetary scientist at UCLA, found the hidden treasure of data while searching through NASA's telescope archives. When he pieced together observations from multiple telescopes, the pattern became clear: jets of gas shooting from the comet's surface had acted like tiny rocket thrusters.

As the comet heated up near the sun, frozen gases beneath its surface expanded and burst out in powerful jets. These jets pushed against the comet's rotation like someone stopping a spinning merry-go-round, Jewitt explained. The jets kept pushing until they reversed the spin completely.

The comet's small size made this dramatic change possible. At just over half a mile wide, the nucleus is light enough for outgassing jets to twist and turn it. Larger comets would shrug off such forces.

Why This Inspires

This discovery shows us that even after centuries of studying comets, the universe still has surprises waiting in archived data. Jewitt's detective work proves that groundbreaking science doesn't always need a new space mission. Sometimes it just needs fresh eyes looking at existing observations.

The finding also reminds us how dynamic our solar system remains. These aren't just frozen rocks drifting through space. They're active worlds that can dramatically transform themselves in response to the sun's warmth.

While Jewitt predicts the comet may eventually spin itself apart from these wild changes, right now it's giving scientists an unprecedented window into how comets behave. Every wobble and spin tells a story about the forces shaping our cosmic neighborhood.

Space keeps showing us that there's always something new to learn, even from objects we've watched for decades.