1

Chemistry / Re: How can I find the optimum ΔH and ΔS for passive T control?

« on: Today at 19:19:40 »

But this pales in comparison to the incredible latent heat of a phase change.

I don't get it. Suppose I have a material that melts/freezes at room temperature. This only works once, and then it's done. Say I want to heat my building in the winter.  I have liquid 'stuff' that freezes as the room temp drops just below where I want it, so it keeps the room warm until it's entirely frozen. Now what? How am I going to get it into liquid state again? I have to turn the heater on and it has all the much more work to do since it has to melt all this nice stuff on top of actually heating the place. It seems I've saved no energy at all, so I'm not sure what you're getting at.
Heating/cooling is all about insulation, not thermal capacity. The more thermal energy that passes from the hot side to the cold side, the more energy it takes to put it back.

Industry, the primary consumer of resources, seems not to care. In the middle of winter I watched the power consumed by the air conditioners in the computer lab. All it needed was a fresh air fan on the roof since it was well below freezing outside, and there they are pumping heat out of the lab to the radiator on the roof, and not even into the heating system keeping the offices warm.
Another building (built for IBM) had the heater break down on an August day.  We had the doors/windows open and still had to wear winter coats because there was no heat to mix with the cold system. Temp was set just like water in houses: by mixing just the right amount of hot and cold, and not just turning off the whole system when it was cool enough. Apparently the utility bill was of no concern.

2

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: Today at 15:01:59 »

A variety of possible recessional velocity vs. redshift functions including the simple linear relation v = cz

That simple formula is useful only at very low speeds. A police radar gun uses it to measure car speeds, but it falls apart once speeds get up to tens of thousands of km/sec.

Recession velocity and cosmological redshift is based on the idea of expansion of space
https://en.m.wikipedia.org/wiki/Recessional_velocity

That page is indeed based on expansion since it references concepts such as v_pec which is an absolute (frame independent) concept. Cosmic coordinates are absolute, unlike inertial coordinates.
Origin's formula for recession velocity is for special relativity, which is not based on expansion. The formula assumes velocity is directly away from the observer and it gets more complicated if there is a significant tangential component.

Again, if we can observe the galaxy then obviously its recession velocity is less than c.

Careful. Relative to an inertial frame, recession velocity is indeed less than c. Relative to Earth's inertial frame, the entire universe is under 15 BLY in radius. Post 61 explains the differences. Hubble's law holds in both kinds of coordinate systems, so recession velocity is still about 70 km/sec/mpc.Relative to say an expanding metric, recession velocity is unlimited, as is the size of the universe, and we can see objects receding at up to about 2.3c (or more if Webb finds a more distant one).
I think only under some ancient theory that put light speed relative to the velocity of the emitter would one not be able to see light from an object receding at faster than c. But all known theories that suggest such things have been falsified.

Dave is rejecting the expanding metric that aligns with an expanding universe as described by BBT. That leaves special relativity unless Dave also rejects the constant speed of light.

Do you mean at any size, even if it is infinity universe? So is it possible that due to the big bang that took place 13.8 by ago the entire universe should be full with matter and in any space that we would be in that universe (even one billion of a trillion ly away) we should see a similar view as we see from our point in space.?

BBT is consistent with a universe without bounded size (cosmic coordinates). The view from the super distance place is the same as from here, per the cosmological principle, one of the premises of the BBT.

The bbt starts while there is no apace or matter in the universe.

No. Please don't tell us what the BBT says. Maybe no matter, depending on how you define it. Normal matter didn't start to form until after inflation epoch.

How can we deliver energy to a universe that already is there?

Don't need to. It's already there as you say.

If I understand Halc correctly

I think you are incapable of that.

a bang in a universe that is already infinite in its size can only set a Bh.

No. A bang at a location in otherwise empty space does that, and also violates conservation laws. Relativity forbids it. BBT happened everywhere, not at a location in space, so there's no black hole.

How the idea of space expansion could work while the space in the early universe is already infinite?

You seem to still be working on the assumption that this size is a number. It isn't. A size is something only applicable to a finite thing. Infinity isn't a number.
Look up discussion on Hilbert's hotel, which wonderfully illustrates how one can go about expanding infinite space.

3

Physics, Astronomy & Cosmology / Re: relativity paradox or misunderstanding?

« on: Yesterday at 18:30:53 »

When light passes through a region with high relative permittivity it no longer travels at C and the denominator in the Lorenz expression will no longer be zero and the photon will now have an inertial frame of reference, albeit for a very short time.

First of all, you're mixing quantum and classic terms. So to keep it classic, we can send a pulse of light through rapidly flowing water.  Make a pipe with a straight section and flat ends and move water in a loop through it fast enough and light entering one end will in principle stand still, yes. So yes, in a medium like water, there is a frame where light moving against the current will stand still. But time doesn't 'stand still' in that frame for anything any more than it does in any other valid inertial frame.

4

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: 22/05/2022 19:35:44 »

Redshift is all about velocity and ONLY about velocity.

Quite wrong. It is coordinate system dependent (as your wiki graph shows), and I can have say a ship approach Earth at say 0.8c and show zero red or blue shift all the way. Lack of redshift doesn't imply zero velocity. Presence of redshift doesn't imply nonzero velocity.

Converting from redshift z to velocity v measured in km/sec is easy - the formula is v = c z.

No valid coordinate system yields that figure, so this too is entirely wrong. It's just a cheap Newtonian approximation for slow moving thing that shows only Doppler effect and no relativistic effects at all.

We should focus only on linear relation.

Why just the wrong one?

Redshift can't give us any indication about the distance.

Unless you utilize the BBT.

In general we can assume that the faster it moves the further it is located.

Not unless you assume BBT. Without that, you're back to square 1.

Hubble verified that there is some sort of correlation between the distance to redshift

Yea, and it wasn't v=cz, a relation that had been discredited over half a century before the recession findings.

Hence, redshift is all about velociy and it is a severe mistake to extract the distance from the redshift.

Do you have empirical evidence (like Hubble does) that such a relation is wrong? You don't. So it's you making the severe mistake of ignoring empirical measurements. This is straight denial of evidence Dave. A new theory might better explain evidence, but if you need to deny the evidence itself, it turns into religion, not science. Again, don't make me lock the topic.

Based on that understanding we can't know the exact distance to that GN-z11 galaxy, however, it is still in a distance that we can observe.

They know it's distance pretty accurately. The error bars are not large.

If one day we would improve our tools, we might see other galaxys that are located further away (with higher or lower redshift).

Only a little further, beyond which galaxies have not yet formed enough to, well, be galaxies. Any more distant galaxy has to be well on this side of the CMB barrier since the 'dark ages' (at least 300M years worth) lie between.

It is not realistic to assume that galaxies that are moving away from us at 1100c (or higher) had been created just 13.8 By ago.

No. If it was moving that fast, it would have been here about 43 million years ago, so according to that bit of nonsense, the universe is only 43 billion years old when those most distant galaxies where here.
Cosmological coordinates very much supports a recession speed of 1100c. A galaxy currently ~15 trillion LY away would be receding about that fast. That's trivially calculated by Hubble's law. We'd not be able to see light from it since it is well outside the visible universe. No light that we see today has ever been further away than a proper distance of about 6 BLY away, or 7 BLY if you use inertial coordinates.

5

Just Chat! / Re: a suitable pseudonym

« on: 22/05/2022 01:22:45 »

I had assumed it was HAL from the space odyssey books, but version c  - so not trying to kill everyone.

So much for not trying to leave an impression. It's short for Halcyon.

NOAX   would have been hard to work out.  No-one would have known it was Non-Oxide Adhesive eXperimental,  or a pop singer.   Best guess -    "No Axe to grind".

Last one was closer.
If you remember my answer to one of your other threads about who we are, I put out an answer about identifying biases (a post which was copied by a spammer bot). To do that, one has to hold a minimum set of base assumptions, so it means no axioms.
So I'm way beyond 'cogito ergo sum' since that statement seems to beg at least two such biases.

6

Just Chat! / Re: a suitable pseudonym

« on: 22/05/2022 00:13:46 »

Consider the abbreviations
People often tend to shorten names online, which I leant by experience.

That they do, which is why I pick a name short enough that it's not likely to happen. Besides, I often need to refer to myself in the 3rd person, and a long name just means a lot of typing.

However, your name is what you start with and why make people start with an impression that is miles away from where you are?

My name here is just a shortened word and not meant to leave an impression. I could have used 'Noax', which isn't meaningful on first impression, but that name does mean something, even if it isn't quite 'wearing your heart on your sleeve'.

7

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: 20/05/2022 20:46:11 »

The Proper distance, comoving coordinates & Comoving distance/coordinates are key elements in the BBT theory.

Coordinate systems (CS) are abstract tools, hardly key elements since any physical system can be expressed to a point using any coordinate system you want. But if you say some object is 10 BLY away, that's a fairly meaningless statement without identification of the coordinate system used to express that distance.

GN-z11
1. Redshift   11.09

A CS independent empirical measurement.

2. Helio radial velocity = 295,050 ± 119,917 km/s (which is almost the speed of light).

The 295050 seems to be the inertial velocity that would yield that redshift. The ±119917 is baffling in that context. That's 40% in either direction, which seems to make no sense. Typo in wiki?

3. Distance ≈ 32 billion ly (9.8 billion pc)  (present proper distance)

Now they switch to CS 2 or 3. If it is 10000 mpc away, per Hubble's law it should be receding at 700,000 km/sec which is about 2.3c, hardly the speed reported just above. But that speed was reported using CS 1, not CS 2. All very inconsistent of the wiki writers. Yes, in cosmological coordinates, it is receding at over 2c and is about 32 GLY away. It, like everything else, is currently accelerating, which is not true using CS 1 (inertial) where GN-z11 is currently still decelerating.

≈13.4 billion ly (4.1 billion pc) (light-travel distance)

Method 4, which is not a CS at all.

Do you agree that the understanding about the light-travel distance is fully based on the BBT concept that the space itself is expanding?

Light travel distance is based on pop articles aimed at people who don't understand the mathematics. No, it doesn't leverage the concept of space expansion at all. No clock would measure that time. No tape measure would measure that distance. I mean, if it traveled over 13 BLY to get here, it must have been emitted from 13.4 BLY away, and got there in only 400 MY, which is over 33c. Are they suggesting GN-z11 was initially moving at over 33c? And redshift of only 11??  Method 4 values are self contradictory, and as I said, only used in pop articles.

However, as we can only measure the galaxies and not the space itself ...
In this example we clearly measure a distance of  32 billion ly. (we call it - present proper distance)

Ooh, you just said we don't measure space, but then assert that we clearly measured the space of 32 BLY. Contradicting yourself I see. Stop asserting things that are 'clearly' when you have no idea what you're talking about. Almost every time you use the word 'clearly', you're asserting something you know to be wrong.
When you use the word 'vital', it means you know you're talking about something that doesn't matter.

However, that measurement breaks the fundamental understanding of the BBT that the age of the universe is just 13.8BY.

There was no mention of age in that distance measurement, so another nonsense assertion.

Therefore, it is vital to "normalize" that measured distance to the total age of the Universe as stated by the BBT. In order to do so, it is stated that the light travel distance is 13.4 billion ly while we measured that the present proper distance (real distance?) is 32 billion ly.

13.4 is nonsense. 32 is relative to cosmological coordinates. Distances are CS dependent, so none of them is more real than any other (except for that light-travel one which is definitely less real).

Hence, could it be that the idea about proper/comoving close the gap between the real measurements to the requested parameters of the BBT?

That's a word salad. No idea what 'parameters' you're referencing here. I don't think you know either.

Is there any possibility for us to look again on all the current observations/measurements without the BBT glass/filter?

Yea. You get redshift of 11 and not much more. Certainly no parallax. You need a model to get a distance from that.

So why do you kill any other candidate that could offer better  explaining for the observations?

We don't, but no candidate does better, and there have been a lot of them. But it doesn't take a rocket scientist (pun intended) to see that the motion of everything we see puts it all right here about 14 BY ago, not earlier or later, but all at once.

Do you agree that if one day we would discover that the real age of the Universe is 100Bly instead of just 13.8 BY

But using CS 1 (but a different inertial frame than that of Earth), it IS 100 BY old (BLY is a distance, not an age).So you can make it any age you want with correct choice of frame/observer.

So, why can't we just release the cosmic time?

You didn't explain what you meant by 'release', but in CS 2 and 3 (cosmological coordinates), time is measured by what is occasionally called 'cosmic time'. It's the time since all the stuff was right here.

What about  Bogie_smiles theory with regards to infinite bangs?

B_S suggests explosions of new material periodically occurring at random locations in existing space which would just form a black hole and not result in any matter at all. If anyone was actually capable of producing a new viable theory, they'd not be wasting their time posting it on a forum.

Would you kindly accept (for just one moment) the idea that the expansion is just in the galaxies while the space itself is fixed and there is no shrink in the universe space?

The galaxies are not themselves expanding. If they did, the space between them would be shrinking then, not growing. We'd see no redshift if there was no recession.
If you mean static space with galaxies moving through it away from each other, that's the first CS. It is known as the Milne solution to the FLRW equations, and only works with a zero-energy universe. Such a universe would currently be 13.8 BLY in radius, a ball with an abrupt edge, and it would look the same (isotropic) from any view point.

8

Physics, Astronomy & Cosmology / Re: relativity paradox or misunderstanding?

« on: 20/05/2022 19:11:02 »

Could you elaborate on "not having a valid inertial rest frame", please.

Per Galilean relativity (proposed 400+ years ago), the laws of physics are the same in any inertial reference frame. One of the properties of such a frame is that light moves at c, but in a hypothetical frame of the light itself, light would be defined as stationary, a contradiction.

I always assumed when the v squared/c squared in the Lorentz equation reached unity the universe would shrink to a singularity and time would cease to exist from the photon's frame of reference.

Except for the work 'shrink', yes. The physics of the universe would be singular, meaning time, space, speed, direction, and anything dependent of these things would be meaningless (which is different from zero or infinite). Being singular means the laws don't apply. They're meaningless. No conclusion can be drawn from them. So you can't say 'light would get from the distant galaxy to here' because there is no meaning to 'here' or 'there'.

So as for the horizon, in intertial coordinates in Minkkowskian spacetime, like will get from any location to any other location. The fact that it doesn't in our universe shows that spacetime isn't Minkowskian. Nobody uses inertial coordinates for really distant things. For one, nothing can travel faster than c relative to an inertial frame, but relative to cosmological coordinates, anything beyond the Hubble sphere recedes from us faster than c. Yes, we can very much see galaxies that recede faster than c and are currently beyond both the Hubble radius and also the event horizon, which is not far beyond it.

(for me, hope I don't start a row!)

... or even a column. 

9

Physics, Astronomy & Cosmology / Re: relativity paradox or misunderstanding?

« on: 20/05/2022 16:17:32 »

It is postulated that a horizon exists or will exist in the future whereby remote galaxies are receding so fast that the light from them will never be seen at some arbitrary distant(from the distant receding galaxies) point in space.

This horizon is due to distance, not due to the recession speed. Light travels at the same pace regardless of the speed of the emitting object. This event horizon is due to acceleration (due to dark energy), similar to the event horizon that forms in Rindler coordinates. Without dark energy, light from a galaxy however distant will eventually reach here.

A photon of light leaving such a galaxy will travel any distance in zero time in it's own frame of reference.

As Origin points out, light has no valid frame of reference. Speaking of distance relative to light is meaningless.

So the question is will the photon reach the the distant observation post or as the horizon theory would suggest will it be lost forever in the permanently stretching fabric of space?

It will not reach the distant observer, but also will continue to move at light speed, not being 'lost' at all.
Similarly, if I accelerate forever to the left at 1g, light emitted from over a light year behind me will never reach me in any amount of time.

FYI, no paradox is suggested anywhere in the OP, except the title. Perhaps you want to reword the title question.

10

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: 20/05/2022 13:30:16 »

I know that Dave will continue to post things that conveys a lack of reading comprehension of this information.

How true this prediction already turned out to be.

Yes, it is changing over time, but today it is constant everywhere.

If you had actually comprehended my prior post, it say that which events constitute 'today' is frame dependent, and relative to Earth's inertial frame (the frame which you seem to imply), it is very much a different value at distant places 'today'.

"the "Hubble constant" itself is a misnomer. It has a value today that's the same everywhere in the Universe"
So what is the meaning of everywhere?

If you had actually comprehended my prior posts, this question has already been answered. It is literally every location in space, no matter how distant.

That graph goes only to about 2 billion light years away, so yea, it doesn't matter much.

Why do you limit the "everywhere" to only 2 BLY?

If you had actually comprehended my prior post, you'd realize that I did not mention 'everywhere' in that sentence. It was a comment about the graph you linked, not about 'everywhere'.

do you confirm that the current Hubble constant everywhere in the entire universe should be 70?

The universe consists of more than today, but H would be measured at 70 by comoving observers at events where the age of the universe and gravitational potential are both reasonably the same as here. This would not be true of distant events 'today' relative to Earth's inertial frame since such events do not meet the criteria above.

However, I still don't understand why do you insist that only the visible / observable universe was in the size of the grapefruit shortly after inflation?

I don't insist on it. I said estimates vary, but that's the approximate size that best explains empirical observations.

Based on the BBT calculation for Hubble constant there is no limit in the size of the Universe.

No, not based on that at all. The Hubble constant is not a function of the size of anything. If you had actually comprehended repeated prior posts by myself an others, you'd stop asking this.

So, why do you insist that only the observable universe can fit into that grapefruit size?

It fit into a lot smaller space than that. That's simply how very much it had grown by the end of inflation epoch.

Could it be that you say this message as you do understand that there is a contradiction?

Not if none has been identified. I only see you contradicting your own assertions, but not that of the BBT. It's like insisting that 2+2=4 is contradictory because you don't know the largest integer.

I assume that you mean that an infinitely-large Universe can't become smaller if all of space is shrinking at a finite rate at a given time.

Depends on what you mean by 'smaller'. If you shrink the universe by half, then the density octuples, so it has by that measure an eighth the volume for any given set of matter. But an infinite universe has by definition no meaningful size. There is no number that represents its size or volume, and thus no different number representing the size after the shrinking. This is what Kryptid means by 'cannot become smaller'. There is no size number to change.

11

New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 20/05/2022 04:48:20 »

my layman level logic tells me that you can't get "something" from "nothing"

With that I will agree.

I maintain that though empty space can be thought of as "nothingness"

Empty space might be indistinguishable from not-space, but I'd not say that it would be nothingness. Time implies a change in state, so time without this change would be equally meaningless. So I'm still agreeing with you here.

unless space has always contained matter and energy

And that too. I'm not saying otherwise. But that statement isn't inconsistent with one big bang. The logic is similar to what holds me up: The floor does, and the ground holds that up, and by the logic you seem to be implying, it must be turtles all the way down, but instead there's a limit to how deep you can dig a hole to find out what holds me up. It isn't 'nothing' holding me up. There is a bottom and it isn't inconsistent to not have that in turn supported from below.

then in order for the universe to be as it is today, you would have to invoke "something from nothing".

But nobody seems to invoke that. It's pretty easily torn apart.

12

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: 19/05/2022 23:38:38 »

Despite this being a reply to Dave, I am posting this mostly to readers who actually care about what some of these numbers mean. I know that Dave will continue to post things that conveys a lack of reading comprehension of this information.

Yes, we can measure the Hubble constant.
and it is constant everywhere.

It is not constant anywhere. It is approximately 1/t where t is cosmological time, and being a function of time, it is continuously changing, not a constant at all.

https://www.researchgate.net/figure/The-Hubble-diagram-or-the-velocity-distance-relation-plot-for-type-Ia-supernovae_fig1_331983227
The Hubble diagram or the velocity-distance relation plot for type Ia supernovae

They don't say how they measure distance in that graph. There are many ways to do so, and they're approximately the same only for nearby objects. That graph goes only to about 2 billion light years away, so yea, it doesn't matter much. But we see galaxies much further away than that, and distances become meaningless without specification of coordinate system used.  My example object is GN-z11, a very distant galaxy. Some typical choices:

1) Inertial coordinates: Only in inertial coordinates is light speed a constant c, and the coordinate system only applies to space that is more or less Minkowskian (flat), which is not true at large scales. In such coordinates, light can get from anywhere to anywhere else given enough time. There are no event horizons. The Milne solution uses such coordinates. Using such coordinates, the current size of the entire universe (relative to the inertial frame of Earth) is a sphere of radius about 13.8 BLY. Distances are measured along lines of simultaneity in the chosen frame. GN-z11 is about 13.5 BLY away, and the light we see now was emitted 6.7 BY ago.

2) Proper distance, comoving coordinates: This is the only coordinate system where H0 is meaningful. There is no maximum speed for anything, so there is no problem with objects at arbitrarily large separations after finite time. Distances are proper distance (measured by adjacent comoving rulers at a given time) traced on lines of constant cosmological time.
GN-z11 is a proper distance of about 31 BLY away and the light we see now was emitted 13.2 BY ago from only about 2 BLY away. Light from sufficiently distant events will not reach us due to acceleration of expansion forming event horizons.

3) Comoving distance/coordinates: In these coordinates, light speed is a function of time (c/scalefactor). Most objects (galaxies) are reasonably stationary and their distance is fixed since the big bang. Distances are proper distance (measured by adjacent comoving rulers at the current time) traced on a line of 13.8 BY cosmological age.
GN-z11 is a proper distance of about 31 BLY away and the light we see now was emitted 13.2 BY ago from a comoving distance of about 31 BLY.  Light from sufficiently distant events will not reach us due to dark energy slowing light speed to the extent that it can never reach us.

4) There is also the dubious light-travel distance, which isn't a valid coordinate system at all, but declares the distance to objects to be c/t from emission event. Light from GN-z11 was emitted from about 13.2 BLY away as measured by light travel time.

The velocity-distance relation plots for freely expanding gas molecules (Figure 2 to Figure 6) are exactly like the velocity-distance relation plot for the receding large-scale structures according to the Hubble diagram; the molecules receding slowly are closer to us whereas the molecules receding faster are further away from us.

That's nice, but the model is Newtonian and doesn't work at all at scales approaching visible universe distances, let alone distances beyond that.

Hence, at any distance and at any direction from us the Hubble constant is always 70 (km/s)/Mpc.

No. Only at events at similar cosmological time to us, which reduces the applicability of the value to coordinate systems 2 and 3 above.

Therefore, the value of Hubble constant should exists at any location in the entire infinite universe.

Again, no. Only to events at similar cosmological time to us.

Hence, if we could jump to a point that is located at 10BLY from us

Ambiguous statement without coordinate system. Using for instance inertial coordinates, jumping to a point located 10 BLY away gets you to a galaxy where the Hubble constant is currently measured at perhaps 100 km/sec/mpc, not 70. This is why choice of coordinate system matters.

we would find that any galaxy that is located in the visible universe of that point has exactly the same Hubble constant.

If you used comoving coordinate system, then you can choose a galaxy a trillion LY away and H0 will currently be measured at 70 there, just like here. There are no galaxies that far away in the inertial coordinates, not in our frame anyway. In a different inertial frame, yes, you can get galaxies at any distance you want, but H0 will not currently be 70 there.

1 Trillion years away and even in the infinity LY away

Infinity is not a distance or a size or a number. Much of your nonsense assertions stem from using it like it was a number. BC has pointed this out. Yes, you can talk about a galaxy a trillion LY away, at least if you use an appropriate frame.

Therefore, as 1/H0 is the calculated age of the Universe, then the age of the entire infinite Universe is 13.8 BY.
Hence, 13.8 BY ago, just after the Big Bang and the inflation the size of the entire infinite Universe was at the size of "grapefruit".

So very wrong. Nobody said that. You keep (seemingly deliberately) dropping the adjective 'visible' from 'universe'. I have a hard time believing anybody is this stupid, so it just means you're trolling when you make nonsense statements like that.
The visible universe was about the size of a grapefruit shortly after inflation. It was much smaller before inflation, but the Hubble 'constant' is entirely inapplicable until after inflation. The universe expanded at an exponential rate during inflation, but only at an approximately linear rate thereafter.

Therefore, as long as we all agree that the Hubble constant is equal everywhere - the Big bang should create our current infinite universe from a single bang.
There is no other option!

There are other options, which is why these things are 'unknown', and essentially do not matter.

Is it possible for the Big Bang to form Infinite Universe in a single bang that took place 13.8 By ago?

You just said that was the only option, and now you're asking if it's even possible. Go figure...

13

Physiology & Medicine / Re: why is my skin so sensitive when I have a fever?

« on: 19/05/2022 16:14:22 »

Is this a known effect?

Very much so, especially for flu. It is similar to heightened sensitivity to sound and light, especially when feverish.

Is there a known (or likely) mechanism?
Is there anything I can do to limit it while recovering?

Apparently staying hydrated is a good way to limit it. Ibuprofen helps reduce inflamatory related symptoms, including the skin sensitivity. I found that acetaminophen does a nice job on headaches and fever, but not so helpful with the inflamation.

Benefit of covid: Our altered social practices have seemingly prevented about two years of all the common stuff I/we usually contract each year. Sorry this hasn't been entirely true for you.

14

Physics, Astronomy & Cosmology / Re: What happens when photons leave the sun?

« on: 18/05/2022 17:27:55 »

When photons are on their 1,000,000 year journey out of our sun

First of all, it is dangerous/misleading to mix quantum and classic physics. Light might take a million year journey as you describe, but a photon is a quantum object which has no real evidence of existing until it is measured (absorbed) by something. It doesn't take a path. So let's stick with light, or a light pulse, both classic concepts.

are they traveling at 'c'

Light in a vacuum travels locally at c. Open space isn't a perfect vacuum, so it might travel less than c, but not measurably so most of the time. By locally, I mean the speed of a given light pulse is dependent on where it is measured, so relative to say an Earth clock, light leaving the sun travels slower than c and gains speed, surpassing c as it nears the orbital distance of Earth. This is due to changes in gravitational potential along the way. But were you to measure that pulse with any local experiment, it would be c in a vacuum.

are photons slowed by the electromagnetic soup called plasma.

Light generated within the sun (by say some fusion event) is very much slowed the progress of light. A given photon will be absorbed pretty much immediately and be re-emitted in a random direction. This random walk might cause any light generated in the core to take about half a million years to reach the surface and actually be emitted into space.

Also, since it takes energy to escape from the sun's gravity well, do photons lose some of their energy and shift frequency upon leaving the surface of the sun?

Frequency (and direction of travel even) of light is a frame dependent thing. Take a dark star emitting no light, but having the mass of our sun. We put a 580 nm (yellow) laser there and point it outward. If you measure it locally, you will measure 580 nm, but if you measure it at a distance of 1 AU, it will be red shifted to a longer wavelength. You might say that is the light losing energy along the way, or you might say that in the frame of the distant observer, the light was that lower frequency all along since it cannot emit move waves per second at the surface than are received at the distant observation point. There's nowhere for the extra waves to build up since the distance stays constant. So from that point of view, the light doesn't change frequency or wavelength along the way. It's constant, and just measured at a different potential.

How much energy and how much Doppler shift is there?

Doppler is due to the changing distance between emission and detection, so as long as the observer stays at a fixed distance from the sun, there is zero Doppler effect in light emitted from it.

You can calculate the gravitational red shift knowing the sun's surface gravity is about 28g and assuming a massless receiver or one at 1g on the earth's surface.

This is incorrect. Gravitational redshift is a function of difference in gravitational potential, not difference in gravitational force/acceleration.  So for instance, I weigh a lot more on Earth than I do on Mercury, but light from Earth would appear blue shifted (not red shifted as you suggest above) from an observer on Mercury. The gravity is under 0.4 g there, but the gravitational potential well is much deeper than here on Earth.

15

New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 17/05/2022 17:37:39 »

Mention a different alternative to "always existed".

This would require one to drop one or more naive bias.

"Always existed" is a phrase only meaningful to objects (a house, galaxy, the weather, etc.) contained by time. So if the universe is not reduced to an object contained by time, but is rather a structure that contains time, then it just exists. This is standard realism, a view held by Einstein and by probably the majority of physics that understand Einstein. If the universe is not a structure that contains time, then all of relativity theory is wrong, and there's not really an alternative thoery that has done its own generalization. So for instance, there's the neo-Lorentian interpretation, which says absurdly that all the equations that Einstein derived in relativity theory can be used to make any prediction, despite the fact that they're all based on premises that are wrong (such as the frame independent constant speed of light). But that's a view (used by nobody that actually has to work with physics) that posits the universe as an object contained by time, and thus is in need of being 'started'.

Dropping the bias of 'universe as an object in time' is not difficult, but if it is for you, then dropping the others will be out of reach, so I'll not go into other alternatives that require more out-of-the-box thinking. This is a science forum. Science is concerned with making empirical predictions, and none of the explanations of the existence of the universe make any empirical predictions, so they're not science.

It's like the question you asked about life elsewhere: If it's beyond the event horizon (which is currently just outside the Hubble radius and well inside the radius of the visible universe), then it cannot be measured by us and by any definition of existence that involves measurability, doesn't exist. That's a very different answer than the mathematical "any nonzero probability multiplied arbitrarily high results in a certainty".

16

New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 17/05/2022 03:08:33 »

The other part of my premise is that the universe has always existed.

I might agree with that part, at least so far as to say there is not a time when there was no universe (or anything else), and a later time when there was. But I consider time to be contained by the universe rather than the other way around. The statement above is open to interpretation.

The alternative is "God did it". Is that where you are going with this?

Heh... There are a lot more alternatives than that, and ones that don't involve positing something even less likely than our universe. Getting into philosophy on a science site are we?

17

New Theories / Re: What is the real meaning of the most-distant-quasar/galaxy?

« on: 16/05/2022 16:42:44 »

Based on the BBT the Universe started from "Planck epoch".

This contradicts the quote you gave which says the Planck epoch is "immediately following the initial singularity". So saying it started with the singularity would be closer. But also, time isn't meaningful until the Planck epoch, so in that way you could admittedly argue that it is the 'start' of the universe.

"All matter and energy of the entire visible universe is contained in a hot, dense point (gravitational singularity), a billionth the size of a nuclear particle."

So, how that "gravitational singularity, a billionth the size of a nuclear particle" could suddenly be considered as Infinite space without breaking the BBT theory?

It doesn't say that. It says the visible universe is that size, not the entire singularity, which, being singular, has no meaningful size/temperature/density/energy/whatever. So what was to become our visible universe was contained in this space under a billionth the size of a particle (which also suggests that a unspecified particle has a size, suggesting a non-fundamental construct of multiple things). Hey, it's wiki, hardly an authoritative source of what represents the current details of the theory.

Therefore, if the Universe started off with an infinite size

It started with the singularity, which means it's singular: It has no meaningful size and other things, which is what they mean by time and space having no meaning. Don't confuse a singularity with a point. The latter has a size. The former is just where physics (certainly classic physics at least, which seems to be the level at which your nonsense is staged) cannot describe the situation.

"the theory describes an increasingly concentrated cosmos preceded by a singularity in which space and time lose meaning (typically named "the Big Bang singularity")."
If you start the Bang when the Universe is already infinite

There you go, giving meaning where it says time and space have no meaning. So no, the universe has no meaningful dimensions at the singularity, but it begins to at the Planck epoch.

So, how can we claim about concentrated cosmos while this cosmos is already infinite?

Learn some grade school mathematics. Concentration (or density actually since concentration seems more of a chemical term) is not measured in meters but rather units of stuff/volume which can be the same for different volumes. Hence knowledge of the size isn't necessary if the density has been measured. For instance, rock (the heavy stuff like you get at say the bottom of the Atlantic) is about 6 times the density of water. Knowledge of the size of the specific rock isn't necessary for that to be known.

If you start the Big Bang from "Planck epoch", and you claim that the early universe was compact, then by definition due to the expansion rate there is a limit for the maximal size of the Universe.

Non-sequitur. By definition of what? Compact? The word as used here just means relativity dense, and as pointed out just above, knowing the density of a thing gives you no clue as to the size of it.

Let's assume that the maximal size of the universe after the inflation is X.

This assumes that it has a finite size, which seems to contradict your typical assertions. The visible universe was perhaps the size of a grapefruit immediately after inflation. Estimates vary considerably.

We know that the expansion rate is based on Hubble constant  (about 70 (km/s)/Mpc).

No, the Hubble constant is based on the current measured expansion rate. It isn't a constant, and it only tells you approximately how old the universe is since it is in units of t^-1.

Therefore, after 13.8 BY with that kind of expansion rate - there must be a maximal size for the Universe.

This absurdly suggests that expansion must stop now since the universe cannot expand further. Do you read your own comments? There is no maximal size, even for a finite size thing, if it continues to expand forever. The visible universe for instance has grown to about 96 BLY across (proper distance along a line of constant cosmological time) and there is no size of it that will not eventually be reached.

If the real universe is bigger than this maximal estimated size, then there must be an error in the BBT.

Or an error in you postulating this maximal size limit. Hmm, which is it you think?

If you claim that the BBT didn't start from "Planck epoch"

The BBT is a theory that started only about a century ago. Perhaps you mean the universe that started from the Planck epoch.

then our puzzled scientists

I'm not locking the topic, but do stop saying that. It is you that is puzzled, apparently by choce. The people whom you are slandering are far more knowledgeable about the theory than any of us and none of them see problems in the places that you do because that's not where the problems are.

So, how could it be that after observing that quasar for quite long time, we didn't observe even one tinny star as it falls inwards with amazing fireworks?

A quasar is about as fireworks as you can get. They consume stellar masses at an insane rate.
Your comments of black holes is very much along the lines of your prior topics, about which you agreed to desist discussion.

Just tell me to stop the discussion in this topic - and I would stop.

But you don't. You're going on again claiming nothing falling into black holes, even the ones that are visibly doing so at the highest rates. So you don't keep your promises to stop.

18

New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 16/05/2022 05:40:00 »

Is this thread in this forum putting me in jeopardy with management?

Not at all. You just don't seem to care that your fantasy cannot possibly work.

19

New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 16/05/2022 01:54:46 »

I'm hypothesizing that "big bangs" are not uncommon events in an infinite universe that is filled with matter and energy across its infinite expanse.

Yes, you just said the same thing in the prior post, and it's still wrong for reasons including the one I gave (among others), and not because consensus is otherwise.

Have you contemplated that kind of universe, or do you stop at Standard Theory and generally accepted science?

New theories are fine if they work. This one requires an entire rewrite of the last seven centuries of physics, which I don't see being posted here.

And note that this thread and these posts are in the sub-forum "on the lighter side", and are not intended to be hard science.

Fine, but you don't accept that it cannot work without said total rewrite of new physics that is completely absent.

20

New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 15/05/2022 23:53:45 »

I'm going with the idea that there is only one universe, and Big Bang type events occur now and then, here and there, within that one infinite and eternal universe

OK, but why post something like that? It has been explained many times how this contradicts all known laws of physics. Any concentration of mass in one place like a new bang in existing space would be an amazing amount of mass in a tiny space, when it's Schwarzschild radius is far larger. The mass would vanish in an instant into its own temporal singularity. The universe would have nothing but a bunch of black holes in it.

Your name off to the left says "Science enthusiast" but 'going with' something blatantly self contradictory like that is science denialism, not science enthusiasm. Science is about learning, not about blind naive assertions.