This Dead Star Is Twisting Spacetime
This Dead Star Is Twisting Spacetime
A pulsar has just confirmed another piece of the general relativity puzzle Einstein predicted, and it’s the first real detection of an effect known as ‘frame dragging.’ And it’s kind of a big deal.
Frame dragging, or lense-thirring, basically states that spacetime will churn like honey around a rotating body with gravitational mass. We’ve seen traces of the effect before around the Earth, but we’re fairly gravitationally tiny, so the effect was hardly definitive.
Enter the pulsar in question. In January 2020, scientists published their observations of just such a special case. The scientists watched a binary star system with some unusual qualities. One star is a white dwarf about the size of the Earth but much chunkier, about 300,000 times the density. And this white dwarf is spinning so fast it completes a rotation in a matter of minutes. That mass and speed means it drags space-time around it much more strongly than Earth does.
This system moves so comparatively quickly that we can literally observe its evolution, in this case using the Parkes and UTMOST radio telescopes in Australia. Their orbit has drifted slightly over time, and the only possible explanation is frame dragging.