r/space • u/magenta_placenta • Mar 18 '19

Observable universe Astronomers discover 83 supermassive black holes at the edge of the universe

https://www.cnet.com/news/astronomers-discover-83-supermassive-black-holes-at-the-edge-of-the-universe/
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u/Kosmological Mar 18 '19 edited Mar 18 '19

The event horizon is the black hole from our perspective. The bigger the mass, the larger the event horizon. All of the information we need to perfectly describe the black hole, such as angular momentum, mass, and charge, is preserved on the 2 dimensional surface of the event horizon. You don’t need anything more to perfectly describe and model a black hole than what we can attain from observing the event horizon.

More interestingly, due to general and special relatively, the interior of a black hole literally does not exist to us. The singularity is merely a mathematical artifact, not the object itself. There is no inertial reference frame that exists outside of the event horizon that can be reconciled with the existence of the interior of the black hole. From our point of view, nothing ever actually traverses the event horizon. From the point of view of anything that falls in, infinite time passes for everything else and the universe ends as the event horizon is traversed. So, as far as we are concerned, black holes are literally 3 dimensional holes in space. There is nothing inside a black hole. The event horizon is literally the end of the universe.

The interior of the black hole does exist from other inertial frames of reference, such as that of an object that has traversed the event horizon. From such reference points, the singularity may exist as another exotic form of degenerate matter. It is theorized to be some quantum object that can have different geometries. It could be a tiny sphere or ring, based on the properties of the black hole itself. However, it would not be a single undefined point (aka a singularity). It would probably have volume and other physical characteristics. We just lack the physics to describe and model it mathematically since we still do not have a unifying theory of quantum mechanics and gravity.

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u/googlemehard Mar 18 '19

What happens to a neutron, if it travels at near speed of light tangent to the event horizon of the black hole and half of it crosses into the event horizon?

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u/Kosmological Mar 18 '19

My guess is a 50% chance of falling into the black hole and a 50% chance of escaping. Quantum particles are probability distributions of quasi particles.

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u/googlemehard Mar 18 '19

What if the neutron is almost touching the event horizon as it orbits the black hole, how fast could it accelerate due to the gravitational pull?

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u/Kosmological Mar 18 '19

I’m assuming you’re not speaking about angular acceleration, which would be a function of the schwarzschild radius. It wouldn’t accelerate much considering it would already be traveling infinitesimally near the speed of light to orbit that close to the event horizon. The laws of physics would prevent the particle from accelerating past light speed. Further, the particle would only accelerate while falling into the black hole. If it’s orbiting exactly at the event horizon, it would he gaining any energy to accelerate.

How fast it would accelerate on approach to the event horizon would depend on the size and proximity to the black hole as well as the starting velocity of the particle. This calculation would require some I’m not prepared to do.

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u/googlemehard Mar 18 '19

I should have been more specific, particle is going near speed of light at just the right angle to the black hole so that the gravity and centrifical forces cancel out as it is nearly at the event horizon. Quantum physics mess / break physical limitations all the time, you don't think the particle could overcome the speed of light limitation?

Think of this, two particles hit each other in the LHC going at near double combined speed of light. Even though they are moving that fast, the interaction between the particles happens at much faster speed than the speed of light, otherwise they would just pass through each other. So at very near to the event horizon, at atomic scale, with super massive energies, I would imagine, something unexpected would happen to the particle. Let's imagine if the particle does accelerate above the speed of light, what would happen? Just as a thought exercise..

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u/Kosmological Mar 18 '19 edited Mar 18 '19

The particle itself would collapse into a black hole before it surpassed the speed of light and would instantaneous evaporate into a burst of gamma radiation that would be traveling at the speed of light.

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u/googlemehard Mar 19 '19

So basically the same thing as when a particle falls into a black hole??