Can a Black Hole "star" commit fusion, would the photons collect inside the star, would the photons degrade into something else?

[Unclear Engineer]

"We don't assume the universe looks the same in every direction, it does."

Sort of true from here, right now.

But, I said it is assumed to be true from everywhere, all the time. That is what is hard to envision and explain.

Same for "the universe is known to be homogeneous." Seeing from one perspective for an extremely limited amount of time is not actually knowing - it is assuming.

And, it actually is averaging. As you said, we do observe voids and clumps along "filaments" that we really don't understand. We just assume that those are the same everywhere, although we are only starting to resolve them closest to us.

And, the BBT assumes that what we see is expanding into nothing, rather than into some larger universe that may be getting other portions locally compressed by our local (but gigantic) expansion.

The BBT assumes that space is finite, and age is finite, but cannot explain how something never was until it is.

Seems to me we should be looking for some explanation that does not extrapolate to impossibility. And, I do not see any reason that it needs to be a cyclic process that takes the whole universe from a tiny spec to billions of light years in diameter and then back to a spec, again, before somehow repeating. Yes, we don't currently understand how that could work. But, then again, we don't understand what appears to be dark matter and dark energy, either. Unless we can find both, we really have not come close to validating the BBT model.

 

[billslugg]

We know the universe is the same for all times since we can see all times. We can see all the way back to about 400,000 years after the Big Bang and every bit since then. It just depends how far away we look. At all distances and in all directions, the universe has the same density and velocity. (With some small differences we can account for). This is why we say the universe is isotropic and homogeneous.

The universe does not expand into something, it is everything. It is a four dimensional analog to the two dimensional surface of an expanding sphere. From all points on the sphere it expands away from the observer. There is no one center of expansion, all places are the center of expansion. If you travelled far enough in the universe you would end up where you started. It is closed upon itself with no edge. Actually, we can see an edge because at some large distance away from us the rate at which space is expanding exceeds the speed of light. So there is an edge to the observable universe.

That we cannot explain what happened before the Big Bang does not preclude the existence of a Big Bang. Our current physics cannot deal with the infinities that accompany a singularity. Maybe someday but not right now.

 

[Unclear Engineer]

A sphere in 3 dimensional space is a curved 2 dimensional space, with a center that is off the 2 dimensional surface.

Last I read, no spatial curvature has been detected in the universe that we can observe.

So, are you saying that the observed universe is a 3 dimensional space curved in time?

And, we really are not seeing our universe in "all times" up to 400,000 years ago. We are seeing the universe in the "now" that is "here", but not any other time in any other place. We infer other times and other places based on the Special and General Theories of Relativity. Those theories explain how a finite speed of light that cannot be measured to change in any direction will distort our perceptions of time and distance when there is a differential in speed between the observer and what is observed that approaches the speed of light. The question in my mind is whether that mathematical inference process is properly done. As currently done, it requires assumptions that we have 20 times the matter/energy that we can find with our best observations, so far, on order to match our observations.

And, there really is no proof that there is nothing and there cannot be anything outside our calculated universe radius. I use the word "calculated" to avoid the circular logic that the definition of the word means there is nothing else. All we can say is that we do not expect to be able to observe anything beyond where we calculate that space is receding from us at the speed of light, carrying all light-emitting things with it so that their light will never reach us. With the BBT, we even calculate that there is more beyond that radius than we can find inside that radius.

If we were falling into a black hole, and already inside the event horizon, wouldn't we also see that the light from objects that fell in after us was being stretched away from us, to the point where things too far behind us would be emitting light that could no longer ever reach us? And, similarly, wouldn't things emitting light in front of us be accelerating even faster than us, such that, at some distance ahead, the light would seem to have infinite wave length to us, thus being undetectable by us?

Yes, I know you think that falling into a black hole must somehow reach an end point because things must be getting infinitely small. But, that is an expected perception of an outside viewer. If as you say, the BBT says we are getting bigger with expansion of our space, wouldn't we also get smaller if our space was getting smaller? Wouldn't that make it look like things not getting smaller as fast as us seem to be expanding?

For that matter, if we were falling into a black hole and inside the event horizon, would we even be able to measure distance in the direction we are falling? Doesn't Special Relativity shorten everything to zero depth that is traveling at speed c relative to us? So, what about an hypothesis that has another dimension that we cannot measure at all, along which we are traveling at the local speed of light? That would be the type of unrecognized acceleration that I mentioned suspecting, earlier. How would that affect our perceptions of the observed x,y,z dimensions and t?

 

[billslugg]

The concept of an infinite universe where every point is the center is difficult to describe. One way to convey the "flavor" of such a concept is to use an analog - that is a simplified but imperfect similar concept. One such "analog" is the two dimensional surface of a sphere and how no spot on the sphere is the center of that surface. Try and grasp that concept then try to extend it to three dimensional space. Of course there are differences, that is why we call the example an "analog".

Yes, we can actually see our universe at any selected time in the last 14 billion years. Pick any time, and look for a galaxy with the appropriate red shift. We have no reason to believe the speed of light has changed over the years. The need for dark matter is based on the velocity distribution in galaxies, has nothing to do with the speed of light. Dark energy is needed to explain acceleration of far away galaxies, also not related to speed of light.

We can't be falling into a black hole as the recessional velocity of galaxies would be approaching the speed of light only on one side of us.

The introduction of extra dimensions is not needed to explain the fact that far away galaxies are receding from us at the speed of light. The simplest explanation is that there was a Big Bang.

 

[Unclear Engineer]

. . .
We can't be falling into a black hole as the recessional velocity of galaxies would be approaching the speed of light only on one side of us.

The introduction of extra dimensions is not needed to explain the fact that far away galaxies are receding from us at the speed of light. The simplest explanation is that there was a Big Bang.

I disagree about the galaxies' recession velocity appearing to be one-sided inside a black hole's event horizon. Remember, it is an accelerating frame of reference. As I said in my post that you responded to, the galaxies that fell in "before" us are still accelerating away from us, so we would see them "receding". Please think about that, again. Remember, objects closer to the center of a black hole will be accelerating towards it at values of acceleration that are greater than those experienced at larger distances. How this would appear to an accelerating observer is difficult to imagine, considering the relativistic speeds assumed in the radial direction. That is why I questioned whether we could even perceive the radial direction. If we could not, then that might explain a lot.

As for not "needing" extra dimensions, you do need to postulate something to explain celestial observations, and the BBT has postulated a very large amount of both "dark" matter and "dark" energy to explain otherwise unexplainable observed accelerations. Just because that is the easiest thing to think about does not make it correct. If "easy" equaled "correct", then we would definitely not have the theories of Relativity nor quantum mechanics.

So, my thinking is that it is time to try some different postulates and see if they can be made to explain our observations without "dark" things being postulated.

I notice that nobody here is interested in thinking about how we could be failing to recognize an acceleration in our Earth-bound frame of reference that could cause apparent fictitious forces and masses, and check to see if accounting for such an acceleration would explain our observations of the cosmos. The effort here seems to be directed toward fending off the concept, rather than exploring it.

Fortunately, there are people exploring many other ideas, some with many more dimensions. There are many avenues of approach, and surely, all but maybe one will be wrong. But, to figure it out, we need to think clearly and probably do some extremely difficult and complicated math to test hypotheses. That seems to be beyond the capabilities of those of us on this forum. So, all we can do here is throw out some ideas and try to think about them objectively.

 

[billslugg]

You are correct that a galaxy falling into a black hole between us and the black hole would appear to be receding. However the galaxies off to one side, at the same distance from the black hole as us, would appear to be falling towards us. The observed pattern of recession would not be radially symmetric.
Occam's razor tells us the simplest explanation is usually the correct one.

 

[Unclear Engineer]

How did you determine what the galaxies "beside" us would appear like to us?

Remember, whatever light they emit would need to be going out ahead so that we catch up to it at an angle to experience it. So, it would make things "beside" us appear to be ahead of us, and rotated slightly towards us, not to mention shifting colors. And that is just for constant speed. Adding acceleration at relativistic rates and I do not grasp all the factors clearly enough to state what it would look like. Have you actually done the calculations to describe the appearance? Are you sure that we could see or measure anything in the radial direction?

 

[Catastrophe]

UE: "Seems to me we should be looking for some explanation that does not extrapolate to impossibility."


Now I find myself agreeing with you.

In general terms, but with particular reference to Billslugg's respected comments, I have to revert to some posts of a couple of years ago, but now buried. However, I find them being suggested elsewhere. This is in respect of expansion and dimensions.

If we are going to use this analogy, as I did here:

Universe expansion,,,,how can the universe expand into nothingness,,outside itself,all there is????? | Space.com Forums

Using the sphere analogy, I developed this situation for the flatlander. It is appropriate to repeat it 10 months later.

For the flatlander, being restricted to the surface of a sphere, the surface of the sphere is all. As the sphere enlarges, that is its radius and surface area (and enclosed volume) increase, all locations in the universe of the flatlander move away from each other. So far the analogy may be said to hold up.

BUT in making this description, we have to admit that an observer capable of perceiving the real situation, is aware that the universe of the flatlander is, in reality expanding in another dimension of which the flatlander is unaware.

This, in my humble view, is useful, at least to me, in trying to understand expansion into itself, i.e., expansion of the Universe, when the Universe is already all there is. My flatlander happily accepts that the surface of the sphere is All. There is no up or down. These are beyond his comprehension. Thus, he is happy with the surface of the sphere, which is his world, his universe.

For the higher dimensional observer (don't bring time into this for the moment, please) the flatlander simply lives on the surface of a sphere. The sphere is expanding - the radius increases, as does the volume contained by the surface. The 'higher' observer understands the flatlander's perspective, but additionally comprehends that the flatlander's world is also expanding in another dimension unknown by the flatlander.

This is how I see the expansion of the Universe. That we are 'flatlanders' unable to perceive (at least for now) the higher dimension underlying our situation.

"If you like, our Universe is expanding into a dimension we cannot understand."


Cat

P.S. If anyone is interested, it goes back to here, and probably beyonf:

Question - Edgeless universe? | Page 5 | Space.com Forums

I think we are in a similar situation to the Ancient Greeks. Everything must go around the Earth. If the Earth moved, we would surely know about it.

 

[billslugg]

Picture yourself in a draining sink, sitting in some shallow water. The closer to the drain someone is, the faster they move. Look towards the drain, they are moving away from you. Look towards the outer edge, they are also moving away from you. Now look sideways, they are moving in tandem with you, but towards you very slowly.

 

[Catastrophe]

And . . . . . . . . . ??? You lost me . . . . . .


On reflection, this looks more like the Big Crunch.

 

[billslugg]

I am responding to Unclear Engineer who posits that we are actually being drawn into a black hole instead of being at the center of an expanding universe. The two possibilities are distinguished from each other by looking at 90° to the supposed center into which we are being drawn.
In the Big Bang expansion scenario, those galaxies 90° to us are moving away at the same speed as all other galaxies. This is what is observed.
In the Big Drain scenario those galaxies at 90° to our supposed direction of movement are not receding from us but are coming towards us slowly. This is not what is observed.

 

[Helio]

The expanding of space includes the space inside our bodies. Problem is the magnitude is too small to be measured. At 60 km/sec/megaparsec, the velocity that the Sun is receding from us due to space expansion is but .01 micron per second. Hardly noticeable.

I still suspect that on an atomic level things are different. The distance should be the same for an atoms electron shells, else emission wavelengths would have been too incredibly short for the early times. The CMBR would not look a 3000K emission, redshifted to 2.7K.

Am I missing something?

 

[billslugg]

I am going to guess that the expansion of space applies at all scales including the atomic. Yes, the nascent atoms at recombination were much smaller but so were the rulers, so the wavelength would be measured the same as an atom today at 3000 °K.

 

[Unclear Engineer]

I don't think that Bill's analogy of water motion in a draining sink is adequate to help envision what an observer would see in a relativistic differential speed situation.

And what I postulated is not just a constant relativistic speed situation, but an accelerating situation where speeds are already in the relativistic range (or "beyond", since we have trouble solving current relativity theory equations inside event horizons). It is not clear to me that an observer inside an event horizon would be able to see anything that is less than 90 degrees away from the radial direction to the center. And for those things at 90 degrees and more, where as well as how they would appear in that observer's sky seems very hard to conceptualize relativistically. Remember, the perception of speeds and timing is not just altered, it is being continuously altered by the continuing acceleration.

That makes it easy to postulate but hard to disprove or prove. I think it requires both some theory development and some substantial calculational effort to test.

Why would it be worth spending effort on such a thought? Two things draw me to it.

One is that our calculations of the observable universe's density leads us to calculate that its visible size would make it a black hole. True, if there is an infinite universe beyond what we see, then it need not be a black hole. But, the the BBT postulates that the same density goes out for about 3 times as far as we can observe - then nothing. So, there is no way that could not be a black hole, unless there is some force that we don't understand at all that is keeping gravity from contracting the universe that we can see - so that is what the BBT postulates and has named "dark energy". I am simply suggesting a different postulate to replace a postulated force we do not even pretend to understand.

The second reason is that our previous experiences with the appearance of forces that are not real come from thinking about motions in an accelerating frame of reference in terms of a non-accelerating frame of reference (e.g., Coriolis force and centrifugal force in rotating frames of reference). So, taking that cue from experience, let's look for an acceleration that we do not already recognize, or perhaps misperceive, as we try to evaluate what we see from our frame of reference anchored to our planet in this part of our galaxy. We are already thinking we might be seeing the postulated "dark energy" increasing the speed of recession over time (e.g., the differing estimates of the Hubble Constant when using nearby stars vs when using the Cosmic Background Radiation), and that is a problem with the "dark energy" postulate, too. But, if what we are seeing is misperceived as expansion, and is really a result of falling towards the center of a black hole when already inside its event horizon, then it would actually make more sense for the speed to be getting faster with time, as distance to the center decreases and gravitational acceleration increases.

But, even if that is true, I do not have the understanding to say that is how we would perceive it. And, I have not yet found anybody who can explain how it would be perceived with the theory and computations needed to be convincing.

So, it is just one of the thoughts that I do not rule out, among some others. I only suggest that it is worth some serous consideration as a possibility.

 

[Unclear Engineer]

I am going to guess that the expansion of space applies at all scales including the atomic. Yes, the nascent atoms at recombination were much smaller but so were the rulers, so the wavelength would be measured the same as an atom today at 3000 °K.

So, if the rulers expand with the universe, how would we measure expansion?

And, if the universe were contracting rather than expanding, how would we know?

Couldn't it "stretch" light emissions from far away stars to look like the light came from a 3000 °K source that was then stretched to look like the CMBR radiation?

 

[billslugg]

We measure distances with the speed of light which does not change.
We know the universe is not contracting or we would see a blue shift, not a red shift.
There is no way a contracting universe could show a red shift and stretch the original 3000°K radiation to microwave lengths. We would have nowhere to put the excess wavelength.

 

[Unclear Engineer]

We know the universe is the same for all times since we can see all times.

I should have commented on this earlier.

What we see, up to this point in local time, seems to be far enough away that we calculate that it would have taken 13+ billion years for the light to reach us here at our point in time and space. So, we assume that we are seeing parts of the universe at different times from "now" back to what it would have looked like here 13+ billion years ago.

We calculate the distance based on a couple of different techniques that involve different sources of light at very great differences in wave length and assumed ages, and assuming "inflation" for the most distant sources. See https://www.scientificamerican.com/article/how-a-dispute-over-a-single-number-became-a-cosmological-crisis/ .

But, I think an observer falling into a black hole could also see the light coming from both the front and behind to be "stretched" to longer wave lengths, approaching infinite length (zero energy), too. How such an observer's perception of that would look like, I don't know, due to the complexities of relativity calculations in accelerating frames of reference near light speed in space warped by high gravity. So, we don't really know if that can be distinguished from an expanding universe by observation. If it cannot be distinguished, then could such an observer look at a much younger part of a pretty static part of the universe from his/her accelerating frame of reference and assume that he/she was looking back in time at an expanding, very old universe that once was extremely hot, instead of some more recent part of a more static universe much farther away from the black hole than the observer?

Going back to the analogy of the expanding spherical surface with inhabitants who do not perceive the radial dimension, I am conceptually groping for a potential lack of perception that is causing us to try to explain observations without properly understanding a key factor. And, to do that, it is important to look at how we came to conclusions that we think are fact based and correct, but are actually based on some key assumptions that we cannot prove are correct.

To me, thinking that we are seeing the conditions of the universe and perceiving them correctly all the way back to 400,000 years after a "Big Bang" is an assumption. Yes, it seems logical at first But doing the computations in detail gets us into needing to imagine so much additional mass and unknown energy that we cannot account for that we do know that we are not perceiving something that is key to understanding what is controlling our universe. Maybe that something really is matter that we cannot see and energy that we don't understand at all. Or, maybe it is not those things, at all. I just think that, until we can find dark matter and dark energy, the BBT is really not validated, and we should keep looking at other potential explanations without prejudice. Just saying "The majority of cosmologists agree," is not scientific proof, it's just "group think".

 

[Catastrophe]

I should have commented on this earlier.

What we see, up to this point in local time, seems to be far enough away that we calculate that it would have taken 13+ billion years for the light to reach us here at our point in time and space. So, we assume that we are seeing parts of the universe at different times from "now" back to what it would have looked like here 13+ billion years ago.

We calculate the distance based on a couple of different techniques that involve different sources of light at very great differences in wave length and assumed ages, and assuming "inflation" for the most distant sources. See https://www.scientificamerican.com/article/how-a-dispute-over-a-single-number-became-a-cosmological-crisis/ .

But, I think an observer falling into a black hole could also see the light coming from both the front and behind to be "stretched" to longer wave lengths, approaching infinite length (zero energy), too. How such an observer's perception of that would look like, I don't know, due to the complexities of relativity calculations in accelerating frames of reference near light speed in space warped by high gravity. So, we don't really know if that can be distinguished from an expanding universe by observation. If it cannot be distinguished, then could such an observer look at a much younger part of a pretty static part of the universe from his/her accelerating frame of reference and assume that he/she was looking back in time at an expanding, very old universe that once was extremely hot, instead of some more recent part of a more static universe much farther away from the black hole than the observer?

Going back to the analogy of the expanding spherical surface with inhabitants who do not perceive the radial dimension, I am conceptually groping for a potential lack of perception that is causing us to try to explain observations without properly understanding a key factor. And, to do that, it is important to look at how we came to conclusions that we think are fact based and correct, but are actually based on some key assumptions that we cannot prove are correct.

To me, thinking that we are seeing the conditions of the universe and perceiving them correctly all the way back to 400,000 years after a "Big Bang" is an assumption. Yes, it seems logical at first But doing the computations in detail gets us into needing to imagine so much additional mass and unknown energy that we cannot account for that we do know that we are not perceiving something that is key to understanding what is controlling our universe. Maybe that something really is matter that we cannot see and energy that we don't understand at all. Or, maybe it is not those things, at all. I just think that, until we can find dark matter and dark energy, the BBT is really not validated, and we should keep looking at other potential explanations without prejudice. Just saying "The majority of cosmologists agree," is not scientific proof, it's just "group think".

"Going back to the analogy of the expanding spherical surface with inhabitants who do not perceive the radial dimension, I am conceptually groping for a potential lack of perception that is causing us to try to explain observations without properly understanding a key factor. And, to do that, it is important to look at how we came to conclusions that we think are fact based and correct, but are actually based on some key assumptions that we cannot prove are correct."

Can you put yourself in the circumstance of the flatlander? Cat

 

[Unclear Engineer]

We measure distances with the speed of light which does not change.

Correction: We estimate distances with the measured speed of light, which we theorize cannot be perceived as different in any direction or over any time interval because of counteracting changes in the perceptions of length and time caused by any motions of the observer (Special Theory of Relativity).

That acceptance of apparent invariance of c comes attached to an acceptance of unperceived variance in the physical dimensions and passage of time that would be apparent to another observer in a different location at a different time and relative speed.

That is a tricky concept to deal with.

 

[Unclear Engineer]

Can you put yourself in the circumstance of the flatlander? Cat

Sure. I read "Flatland" in high school, too.

It isn't hard at all to understand a 2D world when you already understand a 3D world. Even a curved 2D world has rules of observation that a 3D entity can understand.

The real difficulty is for the 2D world inhabitants to understand a 3D world when they cannot perceive the additional dimension. In the book "Flatland", the 2D inhabitants were amazed at the ability of a sphere to appear as a variable diameter circle, seemingly changing size and even disappearing at will, which it did by moving in and out of the 2D plane in the perpendicular direction.

Extending that to us 3D beings trying to understand a 4th, perpendicular physical dimension that we cannot perceive is only useful to the point of suggesting that we need to try to think about it. How to think about it physically pretty much eludes us at a visualization level, but is possible in an abstract level with mathematics.

However, mathematics is a tool for abstract thinking, not necessarily a true description of physical reality, because physical reality may not be correctly conceptualized in the development of the equations to describe the theorized physics.

Just think of all the theories that a 2D being could imagine and mathematically describe for that sphere moving in and out of the 2D plane in Flatland. Maybe that sphere doesn't really disappear when not seen, because nothing cannot become something - so it must be able to shrink to a singularity that we 2Ders don't understand, and be able to inflate itself by a process that we 2Ders don't understand to make itself visible, again. Nothing is gained or lost from our plane. And, when it is not visible, we 2Ders can still hear it speak to us (as was written in the "Flatland" book), so all of its energy must still be here somewhere on our plane, even when it is not visible. So, maybe instead of shrinking, it is really undergoing a quantum level phase change to "dark matter" that we cannot see, even though it is still here.

So, if a 4D being ever comes to Earth and explains another dimension to us, I expect it would have powers that seem like magic to most of us. That would be putting us in the same logical situation as a Flatlander.

 

[Catastrophe]

"The real difficulty is for the 2D world inhabitants to understand a 3D world when they cannot perceive the additional dimension."

"So, if a 4D being ever comes to Earth and explains another dimension to us, I expect it would have powers that seem like magic to most of us. That would be putting us in the same logical situation as a Flatlander."

Exactly.

Car

 

[johnz]

"We use the gravity of the nanometric black hole to ignite nuclear annihilation reaction"

Are we able to do this now? If so, how, please?

Cat

Construction is simple, but testing is very dangerous (the first test Die Glocke was to kill every scientist in a 100m distance ). It is an explosion of a small supernova, repeatedly.

 

[Catastrophe]

Sounds like a good idea.

Cat