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In principle, a black hole can reach a point where it has as much charge or spin as it possibly can, given its mass. Such a black hole is called “extremal” — the extreme of the extremes.<p>These black holes have some bizarre properties. In particular, the so-called surface gravity at the boundary, or event horizon, of such a black hole is zero.
"<p>It had been thought impossible for such black holes to exist. However, new work now demonstrates that such black holes are indeed possible.<p>None have been found, however. Though this seems unsurprising. How would you detect one?
Checking this physics on this kind of thing is really hard. The math saying an object can operate does not tell you how the object comes into existence, for example.
>To understand the universe, scientists look to its outliers. “You always want to know about the extreme cases — the special cases that lie at the edge,”<p>Some of the books I've read recently touch upon things like quantum mechanics and black-holes and that kind of stuff.<p>As a decently technical person but with no formal training in physics, can I generally interpret the study of things like black-holes and quantum physics as the idea of understanding how the physical world behaves as we take limit towards zero or infinity? Is that a correct way to think about it?<p>For example, I've studied probability and statistics somewhat formally in undergrad. The idea that electrons taken on a distribution and are technically "nowhere" until they are observed (schrodingers cat) sounds just like the description of a continuous variable, or alternatively where you take limit on a discrete variable such that it approaches a continuous distribution. The probability of the variable being any value is technically 0 but its state can be observed. It's hard to "truly" comprehend in a realistic since but its what allows us to build statistical models of things
“ Kehle and Unger started with a black hole that doesn’t rotate and has no charge, and modeled what might happen if it was placed in a simplified environment called a scalar field, which assumes a background of uniformly charged particles. They then buffeted the black hole with pulses from the field to add charge to it.”<p>Just finished the article. Surely this can’t be the basis right? I mean everything in the universe is in motion and spins…<p>It did say that spinning work would require extra more complicated math but hmm. Did Hawking et al look at spinning or static black holes in 73 when they did their proof?<p>Imma gonna attempt to read the paper to get more context. I’m sure all the math will go way over my head tho.
Can someone explain the basis for the existence of the maximum charge and maximum spin extrema? Which principles or physical phenomena enforce these limits?
Ironically completing Hawking's work to prove himself wrong. Now it's the physicists turn to prove a better mathematical model, semi-empirically.
I always find it funny how mathematicians try to predict real world behaviour based on some naive assumptions and some random axioms they come up.<p>Obviously reality slaps them in the face almost always and then they are shocked and in disbelief how their "perfect math isn't working, no this cannot be!".
The headline is lying.<p>"In 1973, the prominent physicists Stephen Hawking, John Bardeen and Brandon Carter asserted that extremal black holes can’t exist in the real world — that there is simply no plausible way that they can form. "<p>"The new work [...] demonstrates that there is nothing in our known laws of physics to prevent the formation of an extremal black hole."<p>So they didn't prove him wrong at all. Hawking asserts that it's extremely implausible for these to form, and the mathematicians said "well according to our current models technically they could !"<p>Shameful article. Is there a way to ask for a post to be removed ?