It’s now thought that they could illuminate fundamental questions in #physics, settle questions about #Einstein’s theories, & even help explain the #universe.
…In recent yrs, the amt of data that scientists have discovered about black holes has grown exponentially.
In Jan, #astronomers announced that the #JamesWebbSpaceTelescope had observed the oldest black hole yet—one present when the universe was a mere 400M yrs old.…Recently, 2 #SupermassiveBlackHoles, w/a combined mass of 28B suns, were measured & shown to have been rotating tightly around each other, but not colliding, for the past 3B years. And those are just the examples that are easiest for the public to make some sense of.
To me, a #SupermassiveBlackHole sounds sublime; to a #scientist, it can also be a test of wild hypotheses. “#Astrophysics is an exercise in incredible experiments not runnable on Earth,” Avery Broderick, a theoretical physicist at uWaterloo & at the Perimeter Inst, told me. “And #BlackHoles are an ideal laboratory.”
Broderick says that he studies black holes because they are very simple, theoretically & mathematically.
As he explained it, a #BlackHole has a mass, an electrical charge, & an angular momentum (meaning it can spin). “And that’s pretty much it,” he said. “Their behavior is extreme, but the apparatus is something we think we understand.” Another “simple” way to think of a black hole is as an extraordinary amt of mass in a relatively small space. It exerts a gravitational pull so strong that not even light can escape it.
Imagine the mass of Earth condensed to the volume of a marble; imagine a million suns condensed to the volume of a single sun—that’ll give you an idea of a #BlackHole. Some #BlackHoles are formed by stars that have collapsed in on themselves. Other black holes are thought to have been formed by the inward collapse of enormous clouds of gas. (There are other theories, too.)
To look “into” a #BlackHole—from which no photon or wave or ray ever returns—requires considerable #creativity. The interior of a black hole can only be deduced from changes exterior to it. Active #BlackHoles are encircled by intense brightness & billion-degree heat, given off by matter falling toward them—think of the fire of an incoming asteroid—while the black hole itself is unthinkably cold, a tiny fraction of a degree above absolute zero.
But, when scientists attempt to use these theories to describe what happens in the interior of a #BlackHole, the implications are, as another astrophysicist put it, “a disaster.” Or, as Broderick put it, the theories “give very different answers.”
I am currently investigating an analogy between geodesic deviation from GR and the electromagnetic (Lorentz + Coulomb) force in QED. Once I got all the mathematical details worked out, I will make a thread about this, but I am tripping over the details of how to solve the classical Dirac equation perturbatively in a constant external EM field (mainly distribution-theoretical Fourier stuff). Does anyone here have a good reference on this?
⚛ We've had relativity, the physics of time, genius, the speed of light, the Grand Unified Theory, photons, black holes, quantum physics - but this is the first time Melvyn Bragg and his experts have considered Albert Einstein himself.
Hi. First post on this account. Very recent late Dx #ActuallyAutistic here. Special interests in my bio. Probably should include Autism as a special interest because I'm still in that phase. Nice to meet you. 👋
Teaser: we just got a really cool theoretical physics paper accepted in Phys. Rev. Letters. I am totally excited and I will explain in a few weeks why 😉 #Astrodon#physics#theoreticalphysics