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Orbits are reversible, they are literally cycles.
All you need is to reach enough MOMENTUM to escape from a black hole. Sure you wont reach an escape velocity higher than the speed of light, but your momentum can be as high as you want.
Same for light, light can escape from a black hole, it just gets redshifted. If you fire light at a black hole it gets blueshifted as it falls in, the reverse process is just as common.
You can also just stay in orbit around a black hole and cross the event horizon and then leave and repeat again. Orbits are cyclical.
The whole idea of escape velocity>C is based on newtonian mechanics. Your momentum and kinetic energy can still be as high as you want.
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>>16477247
Dilate.
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>>16477247
Additionally, the idea that some particle or object can just fall into a singularity breaks all the laws of mechanics.
Any two bodies bound by gravity simply establish an orbit between themselves. Collisions are only possible when the objects themselves have a volume, like the earth, that intersects the orbits. The singularity is allegedly a point in space, hence it cant be hit, only orbited around. At the orbit perigee a particle would reach an insanely high momentum, which would allow it to get away from the singularity until it reaches the perigee.
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>>16477275
You are coming very close, there are indeed ways beyond mechanics
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>>16477338
Relativistic mechanics are still mechanics
If an object can fall into a black hole it can also leave it, basically by following the same path back
Because mechanics, including relativistic mechanics are time reversible.
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>>16477247
you must have at least a 100 IQ to post here.
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>>16477247
It's not. I the expansion of the universe continues to accelerate without bound, eventually it will be expanding faster than the black hole is collapsing, and which would cause the black hole to be undone
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what is it about black holes that makes them the number one most popular popsci topic of discussion amongst the brainlet soience fangoys?
is it the comic bookish aspects of the spectacular, unrealistic and completely non disprovable conjectures which go along with the topic that make black holes so popular amongst the scientist posers and wannabes?
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>>16477976
it's the fact that black holes are an extreme. people are always attracted to extremes just based on statistics. looking at a data set, people are more likely to remember the highest or lowest numbers and not some random one in the middle. this applies to astronomy/scifi/etc, since black holes are an extreme in terms of density/as an astronomical object, people are attracted to them more than they would be to a one-in-a-quadrillion brown dwarf.
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>>16477275
>singularity
Since the curvature of spacetime is from the mass of the initial star core, then mass must still be present and be "massy" in order to continue to curve spacetime. How could mas be mass and curve spacetime if had no volume?
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>black holes
When you realize black holes don’t exist or are something completely different from what you’ve been told — it’s like when you found out the Holocaust never happened / dramatically less deadly then what you grew up believing. It’s the feeling of excitement when you experience a paradigm shift. Like meeting your anima for the first time. It’s super-fun and you dig into it for days or weeks afterwards obsessing over it. I think there’s a constant stream of people coming into /sci/ and getting blown away by how black holes aren’t what they’ve grown up believing they are.
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>>16478579
And, more importantly than the black home it exposes how fucking bullshit astronomy and astrophysics is. You find out that this huge field of research is made up out of numerology and finding what they want to find, shit’s crazy.
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>>16478579
>When you realize black holes don’t exist or are something completely different from what you’ve been told
Baby steps, all im saying is this idea that motion towards the black hole (the event horizon) is irreversible.
Because paths are reversible, in relativistic mechanics. You can simply back out if you were to reverse your speed.
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>>16477381
>If an object can fall into a black hole it can also leave it, basically by following the same path back
Going back the same path will put you on the same path you are on right now, because the orbit beyond the event horizon is an unbroken circle
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>>16477247
>If you fire light at a black hole it gets blueshifted as it falls in, the reverse process is just as common.

Here's what happens.

As you blue shift something to ultra extreme frequencies. You're pumping a high energy photon collider. High energy interactions at this level shoot off new matter. The black hole is compacting both time and the energy levels and blow out an absurd amount of new mass in a small space. As in the early conditions of the universe.

Which is what black holes are. They are stasis-incubators for starting the cycle of the universe anew.

And they will do it forever.

You want to make an argument of conservation of mass and energy but it doesn't actually apply to the black hole.

Say you put an apple on the end of a fishing line. You lower it to the event horizon over the span of 100 year seen from earth.

But gravitational time dilation from the event horizon surface being virtually infinite the diminutive apple will approach at the speed of light, time dilated to the angry fist of a vengeful god, glowing with ultra extreme gamma rays, and you then create an entire universe rich with mass and life out of every single photon that event throws off. And then You repeat repeat repeat and the energy never actually become subjectively lower from the BH surface view.
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>>16478781
>High energy interactions at this level shoot off new matter.
We are not talking quantum mechanics here pal
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>>16477247

Black Holes turn space-time inside out. Space becomes time-like. Time becomes space-like. No matter the path you take, you'll end up in the singularity.
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>>16477964

That could only happen if Dark Energy had an exponential growth instead of having a constant density.
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>>16478568

Any kind of energy curves space-time. The curvature of time is what produces gravity, not the other way around. You can see the effects with time-dilation on Earth vs satellites.
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>>16478830
You shine a hand-held torch at the surface of a black hole and what is a casual light beam for you is a peta-billion-yottawatt planck-second pulsed turbo laser for anything at the event horizon. A single hydrogen atom illuminated by it will have an energetic reaction that makes a supernova look like a wet fart. Only that the time dilation difference makes it invisible from the outside.
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>>16478830

Event Horizons cause the same kind of quantum fuckery as singularities that makes us belief that our understanding of quantum mechanics and relativity are fundamentally wrong on some level. Basically, you get different results depending on if you follow quantum mechanics or relativity. Black Holes are interesting because it is one of the examples where it is evident that our understanding of physics is incomplete, even though it might not be solvable.
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>>16478856

There's also some kind of event horizon for any object accelerating. It's called the Unruh effect.
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>>16478837
Why exactly do we think that "dark energy" has a constant "density" (I'm assuming J/m^3 or something equivalent?) Why exactly do we think this abstraction is time-invariant?
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>>16478878

The idea that dark energy has a constant density stems from its association with the cosmological constant [math][math]Λ[/math], which was originally introduced by Einstein as a term in his equations of General Relativity.

The concept of a constant density of dark energy emerges from the observed constant accelerated expansion of the universe. So far, we don't really know if it is really constant or it is variant. We assume that dark energy is vacuum energy (which we don't fully understand yet) and not a variable one from unknown quantum field (such as quintessence), but we are not sure.
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>>16478897
I'm an EE, not a physicist, so forgive me if I'm missing something. I thought there's actually a ton of problems with the lambda-CDM model in cosmology when it comes to observation data. I might be misremembering, but I thought there were actually numerous galaxies we have observational data suggesting that they are accelerating more quickly than others and we don't really have great explanations yet.

As far as I understood, the lambda-CDM model is one that we experimentally know is wrong but we don't have anything better yet theoretically. Am I incorrect in that?
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>>16478904

No, you aren't incorrect. In fact, there's indeed a crisis in cosmology about that. The methods we use to figure it out if the acceleration is constant or not don't give us consistent results.
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>>16478916
Maybe it's because I'm an engineer and not a physicist, but I've grown quite cynical about deterministic theoretical physics modeling. It seems like so many of the modeling decisions we make regarding theoretical physics (e.g., strict conservation of momentum or strict interpretations of Hamilton's principle of action) are made because they make the math easier rather than because they are reflective of "ground reality."

At least in engineering we acknowledge the shortcuts we take (e.g., "everything is a linear system if you sample fast enough") as being approximations/heuristics with tradeoffs. I'm sure there are plenty of practicing physicists who don't think like this, but it seems like the major physics research culture demands "belief" rather than an honest and humble acceptance of the fields limitations.
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>>16478904
If it was 100 years ago we'd already have dropped the lambda-CDM retard hypothesis.

Nowadays we have internet conformity and Consensus enforcement brigades that would've kept the phlogiston alive for all eternity
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>>16477247
You are just spitting a bunch of nonsense because you fail to state clearly what is the model of reality you are using and what are the frames of reference you are using for everything you are describing.
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>>16479482
>You are just spitting a bunch of nonsense because you fail to state clearly what is the model of reality you are using
Plain classical deterministic general relativity with no quantum fuckery
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So….who else never understood how singularities WORK, fundamentally? For example, a gravitational pull so powerful that light can’t scape their event horizon. Even though light is (supposedly) massless it can’t escape…but Hawking radiation CAN? When light reaches the bottom of the singularity, it does…what, exactly? Stop and become particles of matter? How does something which is massless become massive? Like, some kind of light fusion with other things? If it takes more energy than what exists in the universe to reach light-speed, ie, to go into the energy band of light, CAN light ever “stop”? I’ve always just brushed these questions off as something someone smarter than I am understands.
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>>16479860

Nobody knows because we don't have a theory of quantum gravity. Plenty of scientists think the singularity is just running relativity to the breaking point. They singularity might not be real after all.

As for hawking radiation, it is the consequence of quantum fields interacting with the event horizon. Hawking came up with it thanks to a brilliant hack of Bogoliubov transformations to approximate the effect.

The popular explanation is virtual matter-antimatter pairs spontaneously appear everywhere due vacuum fluctuations. Normally they cancel each other out and the energy goes back to the vacuum. But over an event horizon, sometimes one falls and the other escapes, becoming a real particle. Nothing comes out from the black hole. The particle falling in has negative energy. Since mass is energy, it decreases the overall mass of the black hole.

However, this is just one physical interpretation. Space is filled with quantum fields that can oscillate with different frequencies. A particle is like a note on the string, and just like real guitar notes, real particles are composed of many vibrational modes. These vibration modes are still present even without real particles due quantum uncertainty. When a quantum field is a vacuum state, these cancel each other out. Event Horizons cut off access to certain modes of the quantum field, disturbing the balance. Black Holes scatter modes with wavelengths similar to their own schwarzschild sizes in waves packed, ak particles, mostly photons. This radiation is not localized and there's an enormous quantum uncertainty in the location of these particles and appear to come up from all the black hole at once. A distant observer would see thermal radiation a close one would see nothing.

Multiple derivations lead to it suggesting that something like hawking radiation should exist, but without a theory quantum gravity, these are still approximations.
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>>16478837
you can actually "time travel" from the moment the black hole is formed until the end of the universe just as you would travel through "space" in non-black hole space.

But you always move toward the singularity in space dimension. Therefore you can experience the entire existence of the universe, but it all ends at the singularity. And since the universe all ends at the same place, that means all black holes share the same singularity
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>>16478781
You are ready. Look up cosmological natural selection.
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>>16477247
Space and time are emergent properties, not fundamental. Things can and do exist outside of space-time, such as photons. A black hole has such extreme gravity that the concept of space-time literally breaks down. to such an extreme degree that a black hole and everything in it essentially becomes a one-dimensional elementary particle.
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>>16478834
My schizo headcanon is that there is a 4th spacial dimension that we travel through uni-directionally due to space-time binding matter like a plank of wood or a steel beam.
With enough energy/mass/etc. Energy can detatch from space-time and become temporarily 4-dimensional, before either returning to our reality or settling into a different perpendicular universe.
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>>16478869
A similar effect hints at a connection. Maybe a black hole is in fact accelerating along an axis that is traditionally static.
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>>16479860
>….who else never understood how singularities WORK
Im the OP and this thread isnt about singularities. Its about the event horizon.
You can cross the even horizon and come back out. Well not you but some particle could.
Theres just no reason to think a particle that crosses the event horizon cant escape. The idea that you need an escape velocity higher than the the speed of light is stupid, all you need is enough linear momentum which is not bounded.
Photons can also escape, they just get redshifted.
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>>16480238
Linear momentum doesnt work because the path doesn't even exist anymore. You know that meme example of balls on a sheet? Imagine some dropping a bowling ball on it and it just ripping its way through. That hole is the event horizon. You can't get back on the sheet once you fall through it.
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>>16480245
>Linear momentum doesnt work because the path doesn't even exist anymore.
Of course it does. Orbits are reversible.
If the other side of the even horizon was disconnected, it would simply be impossible to cross it.
If it can be crossed, it can be crossed in both directions. Or it just cant be crossed.
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>>16480245
>Imagine some dropping a bowling ball on it and it just ripping its way through.
Horrible analogy as you cant rip spacetime. Pencil trick wont do it
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>>16480245
This is your brain on pop-sci.
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>>16480234
I think the event horizon is misconstructed because we assume earth-time levels of relativistic effects is the universal standard. The physicists egg-heads fail to properly do a correct local space-time transformation for something approaching a black hole and get event horizons and singularities as a mathematical artifact when reality is just that you fall into a spherically compressed space when viewed from the outside but massively expanded infinitely progressing space tunnel from the subjective view, a place that run at a clock frequency that is pretty much frozen from our point of view.
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>>16480249
The difference in timeframes means that once you've crossed the event horizon everything to return to outside have evaporated.

It's like walking back to the 1850s
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>>16480234

It's called equivalence principle. There is no experiment where you can make that would tell you if you are in a gravity field or in an accelerating frame. Someone falling into a black hole wouldn't even notice he has crossed the event horizont, while an outside observer would see you redshift, stop at the edge and dissapear. In principle nothing ever escapes from a black hole. However, quantum radiation is problematic because it suggest a violation of quantum and relativistic effects. For example, if black holes evaporate emitjnf random particles, information is destroyed, which is a violation of quantum mechanics. If we assume that information is enclosed on the event horizon, then the equivalence principle is violated. Maybe information is not destroyed and a remnant is left when the black hole evaporates. Then there is the suggestion that the pair of virtual particles should be entangled despite being separated by the event horizon etc.
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>>16480352
The information passes forward in time into a space that you can only properly access by going after it in close proximity.

It appears that physicists have objectified the concept too much and now think of the event horizon as a hard surface object as opposed to a mathematical observation of warped space time
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>>16480352
>would see you redshift, stop at the edge and dissapear. I
is this meant to take forever?
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>>16480365

That's not the problem. If information was forever trapped in the black hole, this wouldn't be a problem. The problem is hawking radiation. Since hawking radiation is fundamentally random, and ends up with the black hole evaporating completely, as far as we know, information of the original falling object or particles is destroyed forever. Its not easy to get rid of Hawking Radiation either, and you ended up with it through various derivations. We need a theory of quantum gravity to truly understand what's going on.
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>>16480367
stop talking about quantum effects
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>>16480367
Hawking radiation is a result of too much conceptification of the black hole as a hard surface event horizon being a razor sharp divide between black holiness on one side and normal earthy space time on the other where you can split virtual particle pairs across to evaporate the black holiness inside.
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>>16480232
>like a plank of wood or a steel beam
Like a pool noodle?



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