🔭 Black Holes - Quantum Mechanics or General Relativity? 🔭

[BlueInferno]

@ThirstyChickenNugget

Just out of curiosity, what do you think is the fourth dimension? Do you think it’s spacetime, or do you disagree that 4th dimension is spacetime?

To a scientific understanding, I’ll say that the fourth dimension is time or space-time. The vocabulary diverges from here because saying that there is a fourth dimension can conjure those images of science fiction shows where they make up content for that. If we are talking about physical orientation, then we do have length, width, height, and time. That makes four and what I would consider them to be.

String Theory is probably the only research that I would consider valid for the potential for more dimension than we know of.

@ThirstyChickenNugget

Also just wanted a cool fact that I’ve researched in school that there was an experiment conducted by Chien-Shiung Wu using the isotope cobalt-60, and that experiment went against the idea of parity symmetry, the idea that is impossible to figure out whether we live in a regular universe or a mirror universe.

That’s actually really cool. The only thing I’ve heard about her is the fact that she was involved in the Manhattan Project, so whatever theory she came up with, it’s going to be quite old. I bet there are plenty of follow up projects by now.

[Duckling]

@BlueInferno

If you could fly very very very fast, then yes, time would appear to stop for you. As far as we know, there is nothing faster in the universe than light. To travel that speed, you’d already be condensing your mass into a small fraction of it, while growing denser and denser with speed. But light speed, you’d have to be weightless while still keeping mass. That’s also why light itself is weird because of the wave-particle duality it can present itself as

So does that mean that humans will most likely never be able to travel at light speed?

@BlueInferno

Black holes can’t be photographed

I’ve heard somewhere that the photo actually shows the shadow of the black hole and not the black hole itself… But do black holes really have shadows?
Are black holes objects? Or just some weird balls of energy sucking in stuff? How do we know what would happen to humans if we came close to them if no one ever did that?

@BlueInferno

Black holes clash all the time, and it’s an awesome thing to see artificially rendered. The other thing to note is that we don’t have images for this one, all computer simulations. This one is a good example.

Long story short, they combine. There are a lot of fireworks with the waves they send off for us to track (I think the most recent example is 2017).

Ooo, that’s rad does it become double as big then?

@BlueInferno

two-dimensional model.

I never understood that model because it seemed too simplified to me

@BlueInferno

Of course, it’s a three-dimensional object so any way you advance, you’re being pulled toward the centre in one distinct direction.

Ooo, that makes more sense than just “down”
So what happens to stuff that gets sucked inside? Does it just dissolve? Does it power the black hole so it can continue sucking in stuff?

@BlueInferno

Oh yeah, plenty from a physics standpoint. The big four are still gravitational, electromagnetism, strong and weak, but the word ‘force’ as a whole can encompass many more. Most of these are subdivisions of gravity on a controlled surface like Earth. With that in mind, you can have air resistance, tension, applied, friction, normal, and spring forces. Those are all contact forces, something has to be touching the object to make it move the way it does.

Ooo
What’s the smallest one?

[BlueInferno]

@Duckling

So does that mean that humans will most likely never be able to travel at light speed?

We have built objects that can’t even go fractions of light speed. 68,000 meters a second is the quickest we have, 300,000 m/s is the goal to reach. Not to mention how such an operation could even happen. I figuratively use humans as the vessel that’s considering the speed of light, but in reality, we’d die from the g-forces way before them.

Say we keep accelerating an astronaut through space and negate the fact that can die. The faster you go, the heavier you are. At high speeds, you’d be compressed into a near-infinite mass. The more massive, the slower you go. It’s a paradox that would prevent any body with mass from reaching such speeds.

Of course, I’d love to see what we can do soon regarding that.

@Duckling

I’ve heard somewhere that the photo actually shows the shadow of the black hole and not the black hole itself… (…) But do black holes really have shadows?

Black holes don’t have shadows. To make a shadow, you need light and a cast object. Black holes suck in all light. The orange stuff in the photo is only the accretion disc. We will never be able to catch a direct image of a black hole because the light would never reach us.

@Duckling

Are black holes objects? Or just some weird balls of energy sucking in stuff? How do we know what would happen to humans if we came close to them if no one ever did that?

The definition of an object is a material thing that can be seen and touched; black holes can’t be seen or touched. The ‘weird ball of energy part’ is more applicable to stars and other celestial bodies. Black holes are more of ‘a tear in spacetime’.

We know what would happen if we got close from other physical observations. Black holes trap anything that gets close, and we already have tangible limits like the event horizon. The Roche limit is a constant in every celestial body has as the moment where an object (usually tested on artificial satellites for Earth) can maintain a minimum distance before being destroyed from tidal forces. The tidal forces in a black hole are so strong, that the mere distance of an astronaut, head to feet, would vastly differ. They would still be pulled toward the centre but would end up stretched out as the forces caught up to the head. This would happen with any object, be an unfortunate comet, planet, or even another star.

@Duckling

does it become double as big then?

Yeah, the new size would be the rough sum of the previous radiuses.

@Duckling

So what happens to stuff that gets sucked inside? Does it just dissolve? Does it power the black hole so it can continue sucking in stuff?

That loops back to the question posed in the initial thread, are black holes quantum mechanics or general relativity?

@BlueInferno

The biggest example is how quantum mechanics argues that matter cannot be created or destroyed while general relativity points toward the black hole erasing all its information.

@BlueInferno

Once you enter the black hole, every direction is down, and that would suggest that objects at the singularity are essentially gone or taken from the universe. Going back to quantum mechanics, they say that nothing can be destroyed. Hawking radiation is but one example of a method to bridge this gap, but even that isn’t perfect.

So it depends on which system you are choosing to use. My favourite one is Hawking radiation because it’s an incredible theory. Black holes don not expand on the physical plane, the exterior is always a constant size, but the inside at the singularity will have to get bigger from all the mass accumulated. Hawking radiation proposes that black holes lose mass over time as a suggestively faster rate. We’ve never observed a black hole extinguishing itself before though.

@Duckling

What’s the smallest one?

Any of them can be the smallest. If you are observing feathers dropping through a vacuum, there will be no air resistance. If you are holding your phone, there are no spring forces. Tension forces usually apply to objects on a string; friction is for moving objects. That’s the reason these forces are counted mainly for physics problems because they are not always constant. On the flip side, there is no way to remove gravity, electromagnetic, strong, or weak forces from the equation.

[Duckling]

So we’d have to get rid of our weight first if we want to be very fast?

@BlueInferno

We will never be able to catch a direct image of a black hole because the light would never reach us.

Aw what if we use something other than light to get an image or at least an accurate simulation of a black hole?

@BlueInferno

‘a tear in spacetime’.

What if we created an artificial very small tear? Would that even be possible?
And if spacetime can tear, does that mean that it’s like some kind of object or material? What if it’s separating us from another universe which can only be reached by going through a black hole?

@BlueInferno

event horizon.

How did we figure out how large the event horizon is?

@BlueInferno

Yeah, the new size would be the rough sum of the previous radiuses.

Ooo, so what would happen if enough black holes merged to be large enough to affect the entire universe? Would everything stop existing?

@BlueInferno

but the inside at the singularity will have to get bigger from all the mass accumulated.

So does a black hole have endless space inside of it then? Has anything ever been observed to come out of a black hole because the inside got too full?

@BlueInferno

Hawking radiation proposes that black holes lose mass over time as a suggestively faster rate. We’ve never observed a black hole extinguishing itself before though.

How long would it take for a black hole to extenguish itself in theory?

@BlueInferno

On the flip side, there is no way to remove gravity, electromagnetic, strong, or weak forces from the equation.

But there’s no gravity in space, so wouldn’t that mean that it can be removed from the equation?

[BlueInferno]

@Duckling

So we’d have to get rid of our weight first if we want to be very fast?

Yes, though I don’t imagine how you’d go around doing that.

@Duckling

what if we use something other than light to get an image or at least an accurate simulation of a black hole?

We’ve been able to capture the location of the black holes from the gravitational forces it has on other celestial bodies. In terms of an actual image, there is nothing that we, as humans, could see if we didn’t use light. There are plenty of charts out there that rely on separate data, none of it will be visible. The diagrams will merely be artistic renditions or data points.

@Duckling

What if we created an artificial very small tear? Would that even be possible? (…)
And if spacetime can tear, does that mean that it’s like some kind of object or material? What if it’s separating us from another universe which can only be reached by going through a black hole?

This is possible, we just don’t have the technology yet to do so. The Schwarzschild radius has the exact equation for making a black hole. All stars, stellar or supermassive have to collapse to a certain size to become a black hole or they end up as a white dwarf or a neutron star. Everything has a Schwarzschild radius, you have one, I have one, only stars can pull it off. The sun would have to be crushed into the size of a small neighbourhood, and we would have to be condensed to smaller than the nucleus of an atom.

So in terms of an artificial tear, the only thing we have going is to crush an object based on the Schwarzschild radius.

When I say ‘tear’, it’s just a descriptive word. We usually reference the spacetime fabric when determining problems like these, so a tear would be consistent with the wording. It’s not a fabric in reality, but we humans like our analogies.

The theory of alternate universes stemming from black holes is another subject to look into, but not one that we know of yet. It’s like finding the equations before seeing the result. Many of these possible scenarios are determined in our minds, maybe on paper, but the real-world application in something quite different. Schrodinger’s cat in an example of the potential for different realities, but it’s also not proven yet.

@Duckling

How did we figure out how large the event horizon is?

The event horizon is a limit and the size depends on how large the black hole is. Supermassive ones will have a larger radius and a higher event horizon, stellar ones will have a smaller radius and a horizon closer to the singularity.

@Duckling

Ooo, so what would happen if enough black holes merged to be large enough to affect the entire universe? Would everything stop existing?

If all the black holes managed to merge together, then yes, everything would die. The thing to note is that black holes are not going to ever all merge in the foreseeable future. The universe is expanding, everything is moving away from each other.

@Duckling

So does a black hole have endless space inside of it then? Has anything ever been observed to come out of a black hole because the inside got too full?

We don’t know what happens in the singularity yet, only that it does not seem to ever ‘get full’. Hawking radiation is the only known theory if anything leaving a black hole. For now, it’s a pleasurable assumption that black holes have endless space within.

@Duckling

How long would it take for a black hole to extenguish itself in theory?

No one knows yet, and this is all theoretical so there is a chance it doesn’t even happen.

@Duckling

But there’s no gravity in space, so wouldn’t that mean that it can be removed from the equation?

There is gravity in space. Gravity exists everywhere. The comment misinterpretation is when we see astronauts floating in space and thinking ‘ah, no gravity’. It’s just less gravity than what we have on our atmosphere. The gravity Earth extends doesn’t stop with a barrier in the atmosphere, it reaches far out into space until it grows weaker and weaker. The crew on the ISS have their freefall state because the gravity from the Earth is so weak, they aren’t planted to the ground like we are.

[Littlefeets]

Just adding some tags.

A lot of complex information here, but it’s really interesting!