Take that, asteroid!
European Space Agency
Asteroids are the small, tiny rocks that orbit the sun. Too small to be a planet (sorry!), too big to be a micrometeoroid. They were first spotted in the early 1800’s, when the largest of their number, Ceres (now confusingly dubbed a dwarf planet, but that’s another story), finally revealed itself to our telescopes.
While the biggest ones are hundreds of miles across, the vast majority are incredibly small - anywhere from the size of your neighborhood to small enough to fit in the palm of your hand. As you might imagine, there are somewhere around eleventy bajillion asteroids in orbit around the sun.
They make their lazy circles in the vast expanse of interplanetary space between Mars and Jupiter. Despite their distance, they still feel the warmth of our ever-loving sun.
But that warmth in uneven. For one, light itself carries momentum (yes, light has no mass, but who ever said you need mass to have momentum?), which means it can bounce off things and make them move. Slowly, but surely.
Besides reflecting, some of the light gets simply absorbed, the same way that your skin absorbs some infrared and UV radiation.
Lastly, the asteroids themselves are emitting their own light. Not in the visible parts of the spectrum - they’re way too cold for that. But way down in the infrared those things are all aglow.
All this playing with radiation happens at all sorts of angles and all sorts of directions, which means that slowly (and I mean slowly) some asteroids can pick up a force about their axis. That’s a torque. And torque makes things spin.
The end result: spinning asteroids, thanks to sunlight.
The effect had four independent discoverers (apparently astronomers aren’t the most talkative bunch): Ivan Yarkovski, John O’Keefe, Vladimir Radzievskii, and Stephen Paddack. Y-O-R-P. The YORP effect. You’re welcome.
#News | https://sciencespies.com/news/meet-the-yorp-effect-it-makes-asteroids-spin/
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