81–90 of 153 posts
Why do they specify that two of them split only half of the prize, versus just that all three share it? Does anyone care _how much_ of a Nobel prize you have?
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To be fair, the universe will never confront you to such a puzzling situation, as it will kindly squash you under heavy gravity before you come close to any object so massive.
Not necessarily, a supermassive black hole can have quite bearable gravity at the event horizon (as the event horizon radius depends linearly on the mass and the gravity declines quadratically with distance). You still wouldn't be able to communicate your experiences though.
I thought the size only affected the "acceleration" of the gravitational pull based on the distance from the singularity? A supermassive black hole means you will take longer to be spaghettified, but it will still happen and it will happen before you cross the horizon, won't it?
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There's a huge backlog of people who deserve Nobel prizes. The committee is also conservative, and doesn't want to give out a prize for something that turns out to be wrong. Both factors mean that it takes years from discovery to the awarding of a Nobel prize.
It's one thing to allow enough time to pass before a given theory/experiment can be considered as "accepted" by science, and therefore eligible to the award. However, the Nobel committee's rules can be considered archaic to a fault: 3 winners at most, all winners must be living at the time of the award. If you want an egregious example of exclusion, look at the 2013 Nobel prize for the discovery of the Higgs boson. T…
Earlier quoted context omitted.
Not necessarily, a supermassive black hole can have quite bearable gravity at the event horizon (as the event horizon radius depends linearly on the mass and the gravity declines quadratically with distance). You still wouldn't be able to communicate your experiences though.
Doesn't an event horizon imply a gravitational pull so strong not even light can escape? Isn't the effect of gravity the same at the event horizon for all sizes of a black hole? I thought the size only affected the "acceleration" of the gravitational pull based on the distance from the singularity? A supermassive black hole means you will take longer to be spaghettified, but it will still happen and it will happen be…
The press release has a popular science background - https://www.nobelprize.org/uploads/2020/10/popular-physicspr... Highly recommend the illustrations on the press release for a quick overview Cross section of a black hole (pdf) - https://www.nobelprize.org/uploads/2020/10/fig2-phy-en-cross... The Milky Way - https://www.nobelprize.org/uploads/2020/10/fig3-phy-en-milky... Stars closest to the centre of the Milky Way…
An illustration in the press release contains this phrase: "When a massive star collapses under its own gravity, it forms a black hole that is so heavy that it captures everything that passes its event horizon. Not even light can escape. At the event horizon, time replaces space and points only forward. The flow of time carries everything towards a singularity furthest inside the black hole, where density is infinite…
If you think of spacetime as a 4 dimensional geometry, there is no particularly reason to pick out any specific shape of the "time" coordinate. For a given interval in space-time, there is notion of "proper time" that is invariant to coordinate system transformations, so a given observer does have an "ideal" coordinate to use for time. The "proper time" of a given observer could be the space axis of another coordinate system.
Assuming you have enough background in math, what I think is a reasonably understandable explanation is here:
https://www.youtube.com/watch?v=yv2-KPagCQs&feature=youtu.be...
Once he gets through explaining the hyperbolic coordinate sytstem, you can skip ahead to
https://www.youtube.com/watch?v=yv2-KPagCQs&feature=youtu.be...
Space is time line:
https://www.youtube.com/watch?v=yv2-KPagCQs&feature=youtu.be...
A somewhat clarifying picture of it taking "infinite" time to cross the event horizon, without anything interesting happening near the event horizon:
https://www.youtube.com/watch?v=yv2-KPagCQs&feature=youtu.be...
[0] As with any gravitational object, there are tidal forces. However, due to the increasing radius of the event horizon, the strength of the tidal forces at the event horizon decrease as the mass of the blackhole increases.
> Roger Penrose used ingenious mathematical methods in his proof that black holes are a direct consequence of Albert Einstein’s general theory of relativity. Where can I learn more about these ingenious math models in a way that an adult can understand, but one that's been out of math for a while? Is there a good YouTube video? I'm searching but it's coming up with many hour-long lectures by Roger Penrose that seem u…
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Einstein did not believe in gravitational waves either. He also famously added the cosmological constant because he didn't like the idea of an expanding universe.
Do you have a source for this? I thought they were a direct prediction of GR and this link says the same: https://www.ligo.caltech.edu/page/what-are-gw
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The Penrose-Hawking singularity theorems go back 55 years to work starting in 1965. No joke. This has be to near a record in time lag between the work the Nobel committee recognized and when that work was first published. Better late than never I guess (but too late for Hawking, as has been mentioned elsewhere..) EDIT - a detailed analysis: https://physicstoday.scitation.org/do/10.1063/PT.5.2012/full...
I've always thought Nobel prizes are awarded based on the winners' works in that particular year so this came as huge surprise. Too late for Hawking indeed, he could've very well been one of the winners today.
Earlier quoted context omitted.
To be fair, the universe will never confront you to such a puzzling situation, as it will kindly squash you under heavy gravity before you come close to any object so massive.
Not necessarily, a supermassive black hole can have quite bearable gravity at the event horizon (as the event horizon radius depends linearly on the mass and the gravity declines quadratically with distance). You still wouldn't be able to communicate your experiences though.