Here’s Why Black Holes Are Crullers, Not Donuts
When you measure not just light, but light’s polarization, you learn so much more.
It’s been over 100 years since the first solution for a black hole was discovered in General Relativity. For generations, scientists argued over whether these objects were physical, existing all throughout our Universe, or whether they were mere mathematical artifacts. In the 1960s, Roger Penrose’s Nobel-winning work demonstrated how black holes could realistically form in our Universe, and shortly thereafter, the first black hole — Cygnus X-1 — was discovered.
Black holes are now known to range from just a few times the mass of our Sun up to many billions of solar masses, with most galaxies housing supermassive black holes at their centers. In 2017, a tremendous observing campaign was coordinated between a large number of radio telescopes around the world in an attempt to directly image a black hole’s event horizon for the first time. That first image was released in 2019, revealing a donut-like shape surrounding the interior void. Now, a new series of papers has improved upon that image, and we can see it’s not a donut, but rather a cruller, with sweeping magnetic “lines” tracing out the hot plasma. Here’s the new science behind this epic image, and why black holes are crullers, not donuts.
