On Monday the American gymnast Simone Biles made history as the first woman to do a triple twisting double somersault on the floor. Watch the above video and you will be amazed at both the height reached by Biles and the speed of her twists.
Like the rest of us, Biles is bound by the laws of physics and in “The twisty physics of Simone Biles’ historic triple-double”, Rhett Allain analyses her motion with the help of an equation and a few free-body diagrams.
The astronomer David Kipping has a knack for coming up with interesting ideas that really make you think. In 2016 he and a colleague at Columbia University published a paper that described how lasers could be used to hide a planet from distant and potentially hostile observers.
Kipping’s latest proposal is to use the Earth’s atmosphere as a giant lens to create a “terrascope” with an imaging capability of a standard 150 m optical telescope. In comparison, the Extremely Large Telescope (which will be the world’s largest when completed in 2025) will have a 39 m diameter mirror.
Kipping shows that light from distant astronomical objects is focussed by Earth’s atmospheric ring to a point at about 85% of the distance to the Moon’s orbit. There, he proposes, a detector could be placed to create a huge telescope at a much lower cost than a comparable terrestrial or space-borne conventional instrument. You can read more in this preprint on arXiv.
Perhaps the biggest mystery of experimental physics is the origin of the huge signal that has been measured by the DAMA dark-matter experiment in Italy. Operating for 22 years, DAMA has detected an annual oscillation of events that could be the result of Earth’s relative motion through galactic dark matter. The problem is that no other detectors have managed to measure a similar oscillation. In “Testing DAMA”, Jim Daley explains how two new experiments will be trying to confirm the DAMA result.