When NASA astronaut Jasmine Mogbeli spun a dreidel aboard the International Space Station, she wasn’t just celebrating Hanukkah, she was offering an intriguing demonstration of physics.
In the weightless environment, flying about 250 miles above Earth, the four-sided tip keeps going and going and going. It wasn’t until Mogbeli bumped the child’s toy with his camera that it wobbled, tapped the dome window and tipped — prompting laughter from the SpaceX Crew-7 commander.
Mogbeli, who usually celebrates Hanukkah and Christmas with her husband and twin daughters at home, brought a wooden dreidel, a felt menorah and an ornament containing a family photo of her into space. Watch the spinning top in the video posted on X below.
A private astronaut brings an object of mythic proportions to the space station
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This is not the first time Hanukkah, the eight-day Festival of Lights that began on December 7 this year, has been celebrated in zero gravity before. Retired NASA astronaut Jeffrey Hoffman was the first to do so during the STS-61 mission to repair the Hubble Space Telescope in 1993, according to the US space agency.
After Hoffman completed his third spacewalk of the mission, he celebrated with a traveling menorah and dreidel. In a grainy video from the time, he explains what he’s doing:
“One of the games we play is a little dreidel game and it’s something you spin and then you see which side comes out and you either win or lose based on that,” he said. “I was just trying to see how you could rethink the rules of spaceflight since there is no up or down.”
The physics of Earth’s spinning top breaks down into three basic motions, explained Kenneth Brecher, a retired Boston University astrophysicist. Mashable.
First, there is rotation.
Then there’s an orbital effect called “precession” – the direction the top is pointing, which can change as the orientation itself moves around due to torque. This can be seen in action when the pole of a spinning gyroscope slowly traces a circle.
Finally, there is “nutation”, the oscillation of the axis of a rotating object.
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Dreidels and other spinning tops have something called angular momentum, which refers to the object’s distance from its center of rotation. On Earth, the dreidel is slowed down by the air and the table or floor it is spinning on, both of which create friction. As the toy slows down, it loses its angular momentum. Gravity then forces it to stop.
But in space, the rules are a little different. There is no gravity pulling the top down.
“If it was outside the space station,” where there is no air friction, Brecher said, “there would be nothing to stop it.”
NASA astronaut Jeffrey Hoffman repairs the Hubble Space Telescope
Brecher has become somewhat of an unwitting dreidel expert from his career, much of which he has spent studying the spin properties of neutrons and white dwarfs, the dense remnants of dead stars.
Now retired, he is working on building better roofs, optimized in design and materials, after his grown daughter encouraged him to pursue the idea. To learn more about the tops—and watch them spin—visit PhiTOP.com.
“I got interested in it because every astronomical object rotates – planets, stars, galaxies,” he said.