Hi,

I've had that same idea. This leads me to believe that the 'singularity' would be a small shell like a hollow sphere if we assume complete symmetricalness, and a bumpy hollow sphere if not.
That's unless we don't understand how particles can be crushed together at very extreme pressures, which we have no physics yet for. Can they occupy the same space or not. If there is really a 4th Euclidean dimension, then they might be able to rotate and form a long needle like structure where we only can detect one end.

I have not been inside a black hole yet though so I can't say for sure

https://forum.allaboutcircuits.com/threads/are-we-just-living-in-a-black-hole.143342/post-1263458

https://forum.allaboutcircuits.com/threads/are-we-just-living-in-a-black-hole.143342/post-1263581

 

I have watched some of Sabine Hossenfelder's videos. She has a way of explaining many of these questions. Very often, her final answer is "We just don't know and will never know".

She explains away the problem of the Big Bang hypothesis by saying there are two concepts of the Big Bang.
1) The expansion from a singularity.
2) The expansion after the initial expansion.

Her argument is that the current Big Bang hypothesis is (2) and not (1). We don't know that a singularity is even possible. The universe could actually be cycles of a Big Bang and a Big Crunch without having to become a singularity.

https://www.youtube.com/c/SabineHossenfelder/videos

One glaring problem with Big Bang type models is the simple fact that no mass can fall below the Schwarzschild radius without becoming a black hole. Once that happens, there is no escape from the event horizon. No explosion, no beam of light, nothing at all can possibly make its way out.

All of this of course began as an attempt to understand the expansion of space. My conjecture is that (somewhat ironically) this expansion is simply the effects of the ever-shrinking black hole which I believe us to be orbiting right this very moment! If so, since all black holes do eventually evaporate (ie. Hawking radiation), "something must give". Everything trapped within the event horizon, as ALL of its mass must be, would therefore (due to the principles of symmetry) shrink in metric and thus when viewed from any given point in space would yield the effect that things very far away would appear to be receding at an accelerated rate. Which makes sense. Because black holes do indeed evaporate at an accelerated rate. (Incidentally, if we are in fact living within the event horizon of a massive black hole one would expect that the temperature of the observable universe to be getting hotter as well, so perhaps that would another indicator to support such a "black hole universe theory". The Cosmic Microwave Background radiation signal is another excellent indicator - it is the exact signature of a black hole!)

Anyway, the point is, at face value the Big Bang just doesn't make much sense. Something else must be driving the expansion of space. This "dark matter" that everyone keeps talking about, perhaps? Then again, that too is itself rather sparse in terms of actual evidence (to say the very least; it is almost by definition impossible to observe, even indirectly).

https://forum.allaboutcircuits.com/threads/are-we-just-living-in-a-black-hole.143342/post-1263458


There is no singularity. Just a 2D event horizon upon which the entire history of the black hole is irretrievably imprinted.


My theory: the 2D surface inflates into 3D as an object crosses (actually, enters into, it).

Interesting thought! In fact the event horizon may very likely be shaped like a Klein bottle, which does indeed manifest itself as a 2D immersion in 3-space.

That said there is no "falling passed the event horizon" per se (as there are no stable free-fall orbits that exist within or cross the photon sphere). The apparent volume of the object (as seen from our perspective outside of the black hole) is an illusion. There is nothing "within". Neither space nor time exist below its surface. We know that because the Schwarzschild metric admits a singularity not only at r = 0 but also r = S, where S is the Schwarzschild radius of the mass. In any case any object falling toward a black hole, even if "from straight above" would eventually be imparted with so much angular momentum that it would necessarily be orbiting at a rate comparable to the speed of light itself and thus never be able to "fall below" the event horizon in the first place.

 

One glaring problem with Big Bang type models is the simple fact that no mass can fall below the Schwarzschild radius without becoming a black hole.

Please explain. I see no glaring problem there. If everything in the universe is moving away from everything else, how does that cause the things fall below the Schwartzchild radius?

 

You can easily fall below and survive the event horizon of a super-massive black hole as calculated using known physics. Things only really start to get weird as you go deeper in toward the singularity. Once past the event horizon all events on the 'normal' space side become the past so they are impossible to reach for the internal observer but just inside the event horizon of a super-massive black hole for a human sized (the gradient isn't too extreme across the body) object is expected to be easily survivable for at least a few hours as you move to the all destroying center.

 

Please explain. I see no glaring problem there. If everything in the universe is moving away from everything else, how does that cause the things fall below the Schwartzchild radius?

In other words there is no way to confine all of the mass of the universe in to such a small space from which the Big Bang is supposed to have "emanated" without necessarily reaching its Schwartzchild radius.

You can easily fall below and survive the event horizon of a super-massive black hole as calculated using known physics. Things only really start to get weird as you go deeper in toward the singularity. Once past the event horizon all events on the 'normal' space side become the past so they are impossible to reach for the internal observer but just inside the event horizon of a super-massive black hole for a human sized (the gradient isn't too extreme across the body) object is expected to be easily survivable for at least a few hours as you move to the all destroying center.

Again, you CANNOT "fall below the surface" of the event horizon. Full stop. To do so would be entirely inconsistent with the known properties of black holes. That said, from your perspective (being extremely compressed due to length-contraction) there would nonetheless be plenty of space to "move around" in.

 

Hi,

Are you trying to say that you want to track the movement of the star over time relative to earth?
If so, how does that help understand the size of the universe?

By 'size' I mean the total size or the observable size, either one which fits what you are looking to figure out.

Hi @MrAl!
The relationship with "size" was about the quantity of objects, not the spatial or temporal extension.
However, thanks to the conversation with @Ya’akov and @MrChips it was understood where the "bug" in the reasoning is.

 

In other words there is no way to confine all of the mass of the universe in to such a small space from which the Big Bang is supposed to have "emanated" without necessarily reaching its Schwartzchild radius.

It is explained here.

 

Again, you CANNOT "fall below the surface" of the event horizon. Full stop. To do so would be entirely inconsistent with the known properties of black holes. That said, from your perspective (being extremely compressed due to length-contraction) there would nonetheless be plenty of space to "move around" in.

The event horizon is not a barrier or a surface in black hole theory and you must take into account how Relativity affects the external observers and the actual person observing. An Event Horizon is merely the maximum distance from a Singularity where the gravitational pull of the Singularity is strong enough to prevent light from escaping. The gravitational effect of a super-massive event horizon (in isolation from other effects like stars and matter falling in) would be similar to a bird on a high tension line. The absolute level is high but the gradient across the body is small.

 

It is explained here.

The article linked doesn't really explain anything. There are some hand-wavy references to the effect that it isn't the density but the (lack of) difference in density that matters, or that it was just too uniform for a black hole to form.

Bottom line, the Schwarzchild radius of all of the matter in the universe (estimated to be at least 10^53 kg) would be more than 10^23 kilometers. That is something like 10 trillion light years, much MUCH wider than the observable universe itself!

The event horizon is not a barrier or a surface in black hole theory. An Event Horizon is merely the maximum distance from a Singularity where the gravitational pull of the Singularity is strong enough to prevent light from escaping. The gravitational effect of a super-massive event horizon (in isolation from other effects like stars and matter falling in) would be similar to a bird on a high tension line. The absolute level is high but the gradient across the body is small.

What I am saying is that there is no "where" beyond that point. If you could "put your hand through" it would appear on the opposite side (bearing in mind that there is no "opposite side" proper because we are dealing with a Mobius manifold). Again, the innermost boundary of the event-horizon is a singularity. That is no mere mathematical anomaly but a statement about the true topology of black holes.

 

What I am saying is that there is no "where" beyond that point. If you could "put your hand through" it would appear on the opposite side (bearing in mind that there is no "opposite side" proper because we are dealing with a Mobius manifold). Again, the innermost boundary of the event-horizon is a singularity. That is no mere mathematical anomaly but a statement about the true topology of black holes.

That, IMO, is a meaningless statement about a human surviving crossing the event-horizon. The singularity is an unphysical artifact (beyond current physics) of the theory. The singularity is the point at the center of the black hole where the curvature becomes infinite. The event horizon (something we have good physics theories to explain) and the singularity are two different things
Sure, there is a 'where' for the observer inside the event-horizon, we have no real theory of exactly what that "where" is.

 

The singularity is an unphysical artifact (beyond current physics) of the theory.

Lemaître and others have also argued as such to be the case. However it should be noted that Einstein himself believed otherwise, that the singularity at the event horizon was real and not just some kind of "coordinate artifact".

 

Lemaître and others have also argued as such to be the case. However it should be noted that Einstein himself believed otherwise, that the singularity at the event horizon was real and not just some kind of "coordinate artifact".

Hi,

That's interesting because the total effect of gravity is often based on the size of the objects vs the distance apart, such that each object is viewed as a point mass. Does anyone change their calculations if the top of the empire state building points more towards the sun than more away from it, or the position of the top of Mount Everest.

 

Lemaître and others have also argued as such to be the case. However it should be noted that Einstein himself believed otherwise, that the singularity at the event horizon was real and not just some kind of "coordinate artifact".

The Event Horizon is the absolute horizon that a distant observer can't observe. The local infalling observer is still in local (relative) time as it passes though the event horizon and will be in local time until time is meaningless.
Singularity is not so much a place, it's a time you can't avoid.

The only way to know for sure is to jump in.

 

That's interesting because the total effect of gravity is often based on the size of the objects vs the distance apart, such that each object is viewed as a point mass.

I take it you meant the mass (not size) of the objects?

Does anyone change their calculations if the top of the empire state building points more towards the sun than more away from it, or the position of the top of Mount Everest.

You seem to be implying that the configuration of matter within a Schwarzchild radius has some effect on whether or not a black hole forms in the first place. Evidence?

But yes, Newton's standard equation G*m1*m2/d^2 is indeed a somewhat imprecise point-like approximation. A much more accurate approach would be to find solutions to the Einstein field equations for the particular system in question.

The local infalling observer is still in local (relative) time as it passes though the event horizon and will be in local time until time is meaningless.

Singularity is not so much a place, it's a time you can't avoid.

Okay, so he falls in and suddenly time is somehow meaningless. Sounds like a scene from Kubrick's "Space Odyssey"! But seriously, what does that even mean?

The only way to know for sure is to jump in.

In that case, you'd better hope I am right!

 

Okay, so he falls in and suddenly time is somehow meaningless. Sounds like a scene from Kubrick's "Space Odyssey"! But seriously, what does that even mean?

Simple, it means you're dead.

 

I take it you meant the mass (not size) of the objects?



You seem to be implying that the configuration of matter within a Schwarzchild radius has some effect on whether or not a black hole forms in the first place. Evidence?

But yes, Newton's standard equation G*m1*m2/d^2 is indeed a somewhat imprecise point-like approximation. A much more accurate approach would be to find solutions to the Einstein field equations for the particular system in question.

Hi,

Yes I meant mass that's how I ended with the idea of the point mass. The reason I brought up the distance between objects was because the farther they are apart the less important the individual features become when deciding where this point (x,y,z) is inside the object. This is in reference to the idea of a coordinate artifact or not.
The question for me then becomes how do we measure this singularity. If we do not know the details of what is inside, we must be using the point mass version, where we can't tell if it is a coordinate artifact or not. I do not know enough about black holes to argue this to the final resolution however. An alternative view is if inside everything is highly symmetrical, we reach the same conclusion (ie several Empire State Buildings symmetrically distributed across several locations on the earth leading to an average density and center of gravity smack dab in the very x,y,z center of the mass).
Since a sphere, for one, has this property, can we tell if the singularity is real or a coordinate artifact. Is there any evidence that leans one way or the other.
BTW, I like your idea of using the description of a "coordinate artifact" to make the idea in question clearer.

 

Wow! A paper featured in this month's American Journal of Physics seems to support my theory. The authors produced a graphic to illustrate their observations.

The article goes on to say:

B. Black holes and the zone forbidden by gravity

In Fig. 2, gravity and quantum uncertainty create large forbidden triangular regions where no known objects can exist. All Schwarzschild black holes, from the smallest Planck-mass instantons to the super-massive black holes (SMBH) at the centers of the largest galaxies, lie on the diagonal m∝r
line labelled “black holes.” Black holes lie on this line because the radius and mass of a Schwarzschild black hole are linearly proportional,29
rs=2Gc2 m.

Interestingly, the “Hubble radius” (representing the Universe) also lies on this black hole line (Sec. III A). The “forbidden by gravity” region illustrates that all objects of a given mass are larger than a black hole of that mass, and all objects of a given radius are less massive than a black hole of that radius.

So there you have it. We could very well be orbiting an uber-massive black hole right at this very moment!

According to my calculations it should be extremely cold, just a few degrees above absolute zero in fact. Also while all black holes do eventually evaporate via a process known as "Hawking radiation", growing ever hotter at an accelerated rate, ours is so large and cold that you could multiply the current "lifetime" of the universe times the number of microseconds since and ours would still not have evaporated completely by such time.

But really the beauty of the whole thing is that it actually vindicates Einstein. He may have been wrong about the cosmological constant but only because he could not have possibly foreseen that the expansion of space might be "fueled" by the effects of falling into something which his own theories predicted (ie. the black hole). But now it makes perfect sense. Space only appears to be expanding...everything within its event horizon is shrinking at an accelerated rate!

 

We could very well be orbiting an uber-massive black hole right at this very moment!

No. Our universe is the black hole. Actually, the 2d EH infated into 3d space .

 

No. Our universe is the black hole. Actually, the 2d EH infated into 3d space .

More or less, considering we would be indistinguishable from the black hole as seen from the perspective of the universe in which it resides. And yes the topology of such objects is truly mind-bending (although there seems to be quite a bit debate about the actual configuration). Mathematically, it has more in common with a torus than it does a sphere!

 

...from the perspective of the universe in which it resides.

That universe has experienced a heat death long ago. We are all there is.