Expanding, or Contracting?

If the visible universe were "contracting", there would be a blue shift of observed objects.

We don't see this, which is why we perceive the universe as expanding, and at an increasing rate.

No, that's why I posted this.

The galaxies closer to the black hole are falling inward faster than we are, so they are moving away from us. Likewise the galaxies further from the black hole than we are, are falling in at a slower rate than we are, so we are moving away from them.

We'd only see a blue shift for a few galaxies in our vicinity.

Galaxies in every direction are red shifted.

Yeah, that's what I meant.

I don't know which black hole he is referring to, ("the black hole") since we cannot actually observe something in a black hole...

Not to question the validity of your reference, but:

"Welcome to: physilink.com

This Web page is parked for FREE, courtesy of GoDaddy.com.

Zero content on that particular homepage.

Anyhow...any other references? And if so, how many of those blue shifted galaxies have a black hole at the center?

EDIT: Ah, PhysLink.com...but from that very same reference:

"So, in a nutshell, if a galaxy's peculiar velocity is toward us and larger than its Hubble recessional velocity, then its light will appear blue-shifted. This is possible for galaxies that are nearby like Andromeda, but as galaxies get farther away, their Hubble velocities dwarf any peculiar velocities they might have. As such, it's better to study far away galaxies when you're interested in how the universe is expanding."

The universe is expanding as a whole...

Sorry about the typo.

Yes, I know the universe is expanding. I know. I've got a masters degree in astrophysics. (Really.)

The purpose of my post was to 'think outside the box'. (And yes I know that's a cliche').

As far as I know, no one has ever pointed out that redshifts could occur if the universe was falling inward. I like the idea that this is true, even though counter-intuitive.

"As far as I know, no one has ever pointed out that redshifts could occur if the universe was falling inward."

But not with the same 'Hubble's law' in every direction. Look at the gravitational potentials in your original diagram in 3 spatial dimensions. The large scale redshift then can't be isotropic, because it would also depend on the gravitational potential of the emitters and receivers..

If however the universe was in an isotropic contracting phase, with no point that it is "falling to" (same potential everywhere), we would have seen only blue shifts on the large scale.

-J

Thanks to your admission of qualification I've got a masters degree in astrophysics , I will not enjoin the discussion intellectually. I wish to point out though, that you may have to fall back on whisky and women, since what you have postulated cannot be proved in this forum.

Agreed, they all have their proper motion, so some will be shifted red and others blue. Hubble's law says that the average becomes redder, proportional to distance.

One can be a success throwing lots of theory however, Laws are limited and absolute.

You can break and dismiss a theory anytime, but would it not be called a magic breaking just one law of nature?

One interest or insight that will probably be the best and finale discovery of all times is converting heat and light to mass or matter.

The end state or product of a black hole is pretty interesting to see and observed (energy cycle end state).

Yet, it's sad because even Hawking said a black hole also generates entropy.

Where then all the mass or matter go?

The edge of all discovery would be mastering the conversion of energy(Wave to Particle Conversion)

If one finds it, he must be a God by then - able to reconstruct the universe.

the black hole? which one?????????they're all over the place

I vaguely remember somebody else discussing this idea as a possible universal red shift explanation. I think that it was one of the candidate explanations prior to the big bang theory predicted that a residual cosmic microwave background radiation level would be present if the big bang happened. Then a couple of electrical engineers in Murray Hill were trying to figure out why their new microwave antenna picked up a microwave level in all directions that they could not explain...

Problem solving begins with the easiest most straight forward explanation, this continues as the answer until it is proven false...

Yeah, it came down to either Cosmic Expansion or bird poop in the feed horn. Cosmic expansion is much cooler.

I've wondered at times if redshift was caused by light's zig-zagging path through the universe, rather than receding galaxies...

http://calgary.rasc.ca/redshift.htm

At cosmic distances (z > .05, or d > 700 Mly), the path length increases due to the bending of the light by intervening galaxies are negligible in comparison to the cosmological redshift.

In cosmology terms, we should not think "recession speed" any more (that's ancient), but rather that the wavelengths have been stretched by the cosmic expansion.

-J

Cosmic expansion......let's hope it doesn't pop...

http://www.einstein-online.info/elementary/cosmology/expansion

Plus, the signal was still there (maybe better) without the bird poop.

By the way, I think this cosmic hole will not be black, due to gravitational radiation (baloney) it will be the giant big red hole in the sky. We have no such A hole, therefore the matter is closed.

Wait, let me put my glasses on..........................................................................I'll check.

Yes this concept has crossed my mind, But! as we approach the black hole, gravity increases, so if this is the case we should be able to detect an increasing in gravity?

Regards JD

I would think if some massive black hole was acting as a cosmic drain that you would see that in the proper motion of the stars.

What we observe is that every galaxy seems to be moving away from us no matter which direction you look. There are exceptions, such as the Andromeda galaxy, which is actually moving towards us.

However, the data collected to date does not support this cosmic crunch and the idea that the observed stellar redshift would appear the same posits that we are at the far end of the universe - the last one down the drain, so to speak. That doesn't seem statistically likely nor does observation support that notion.

Intriguing...

The galaxies "ahead of" and "behind" you could show such red shifts, but galaxies "to either side" would show blue shifts as they converge toward each other.

Maybe some other geometry (perhaps hard to visualize) could avoid that anisotropy.

In Macro "classical"-thermodynamics perspective. Expansion always means losing heat energy. 2nd law of Thermodynamics also supports expansion of the universe in away, the universe is losing material energy being converted to light and heat.

If you base your hypothesis on vectors of galaxy and stars, you have lots of probability to get lost, since the universe has no permanent static reference.

However, we have 2 absolutes existed in Thermodynamics we can always rely on.

Absolute Pressure and Temperature- inevitably this holds true to all the laws of nature, including the soundness of your hypothesis.

That premise seems to be untrue. While the Second Law holds true for a closed system that is not complex, the universe is complex and dynamic when taken as a whole.

First, space is expanding and its energy density is calculated at 10^93 grams per cubic centimeter (the common term is to use mass-units) by Wheeler and Misner and is reflected in the cosmological constant, Λ.

That means that the net sum of vacuum energy is also increasing in the known universe as space expands, which I think complicates your assumption.

Therefore, your assertions neglect the absolute Temperature and Pressure might as well the 3rd law of thermodynamics.

Even if there is a multiverse, it will be the same absolutes (Pressure and Temperature) isn't?

In the premise of absolute Temperature and Pressure, all system will be considered close.

Imagine if absolute Temperature and Pressure becomes negative? Would it be possible?

Entropy will be reversed towards negative production and so on and so forth if that's the case.

Space is the reference point to all that there is with its absolute value irrespective of energy density or whatever it has.

3rd law states that at absolute 0 kelvin all processes runs efficiently and at ground state. What could be more to it?

I don't think my post negates any laws of thermodynamics, it just posses the prospect that the universe is more complex than a simple theoretical adiabatic system in some text book.

Unless you consider those extraneous factors you can't draw the simple conclusions you did in the post I responded to. Do you agree?

No one has mentioned "dark matter" where the theory is the density remains constant. An extraneous factor? Possibly a "prospect that the universe is more complex than a simple theoretical adiabatic system in some text book."

"No one has mentioned "dark matter" where the theory is the density remains constant."

I suppose that you meant "dark energy"? The density of dark matter thins out with expansion, just like ordinary matter. Dark energy may be a simple cosmological constant, which means is works like a vacuum energy with constant density as more space forms. It is not yet ruled out that it may have a variable energy density over time, i.e. a quintessence type or energy.

Nope, I do not agree. It could not be even called(the analogy of the universe) theoretical adiabatic system- the author lose insights.

All system needs surrounding to work (higher state to ground state). Equilibrium is one in which (No chemical, thermal, physical interaction takes place).

In the state of absolute Zero Pressure and Temperature(ground state-a reservoir-one in which can not be affected by any means or quantity exist there is) all processes(interaction) cease so as to any system, system could be any universe.

Any universe could only exist closer to this ground state. Other wise, they don't exist at all.

Weird assumption and insights from this modern age physics that the universe together with its space expand -- to WHERE?--don't tell me to SPACE? see, a 5 year old kid could dismiss this flawed theory, that the weirdness of the universe is like in quantum mechanics, that spaces in between particles are compose of energy and that particles created also space as its intrinsic property.

if so that it is like the quantum mechanics, implications would be that at the edge of the expanding universe, absolute Temperature & Pressure are offset than to where we are right now, more or negative than our absolutes Temperature and Pressure. - Is this a sound theory? I say nope.

We and all are bounded and trapped by these absolutes, beyond this is none existence.

The equation that simplified all (Einstein's objective) already exist prior to all his works and studies. He even used it every time.

That equation is Zero "Nothing".

this junior astrophysics thread is overloaded with red shifting Bozo hypothesis

"Do you really believe that the moon isn't there when nobody looks?" Albert Einstien

Oh quit it!!

Sorry, I can't follow your train of thought. You seem to jump tracks and begin talking about a different subject (multiple times) that has no relation to the original claims we were discussing.

Every thing comes up to a unity. An extraordinary claim, requires an extraordinary proof.

A Quantum Mechanic walks into a bar....

someone from a parallel universe will have to finish the joke.

A Quantum Mechanic walks into a bar....someone from a parallel universe will have to finish the joke.

He said 'OUCH'

... it was an iron bar.

At least across the pond is about as close to a parallel universe as I want. Cheers mate! If you are every here, look me up, and we might have a spot of Earl Grey. I don't drink, but I could spot you for a Killian's Red Ale, if you like that.

If the universe is expanding adiabatically (without any source of enthalpy transfer to it), would we not be colder than Ebenezzer's sneezers by now? I understand there are limits to coldness, but anything below about 4°C is overdoing it just a bit IMHO, I prefer balmy days, and cool, dryish nights.

My personal preference is that Barrack Hussein Obama go stand on another planet that is expanding adiabatically away from the White House. Also, I am going to write Santa Claus (Jorrie) and ask if we can have the Universe expand isothermally for a change.

This forum is being led by the nose here...wakey wakey!!

I think recent evidence indicates a few thousandths of a degree below 0K was achieved in a lab somewhere, but I can't find the reference. Shroedinger's cat ate it.

find your answer here...http://wiki.polyfra.me/

Interesting idea, but I guess the answer lies in the statistical number of red and blue shifts to push the argument one way or another BUT

A related idea from Stanford per I Riofrio (a scientist) is that the red shifting that is observed in the universe might arise out of time-space coefficients not remaining constant over time (or something like that). The important new equation is GM = tc^3, which is apparently readily derived or consistent with known physics, and where G is Newtons constant, M and t are Mass and age of the universe.

A search will easily find the link http://www-conf.slac.stanford.edu/einstein/talks/aspauthor2004_3.pdf, and other links.

I know next to nothing about the complex maths of the universe, as you will guess as I throw in a possible theory.

If the universe looks the same in all directions (up down sideways) then you cannot know if a telescope is pointed at the origin, but we do know that the most powerful telescopes find matter so far away that the time for light to reach us must have started out at the beginning of the big bang.....a singularity?

If we then say that this matter was on the edge of the singularity at that point in time, the event horizon, and whatever direction a telescope points we see the event horizon, then we must be inside it.

Our universe is not getting bigger. We are getting smaller. But we do not perceive this because time itself is changing.

And assuming C is constant, the distance measured by this 'shrinking' time creates the illusion of expansion. where the same 'shrinking' of time causes an 'acceleration' that manifests itself as gravity. The change in 'time' is not constant over distance but of a proportion that varies with 'perceived; distance, that appears as red shift.

So yes!, we could be falling into a black hole, or perhaps we are already in it below the event horizon, and falling into a singularity.

I pose the theory, because a confirmation that I could be right could help with fault-finding on my gas boiler.

"Our universe is not getting bigger. We are getting smaller. But we do not perceive this because time itself is changing."

The problem with that is that galaxies themselves (as well as its contents) are still the same size, but the distance between galaxies have been growing.

There are galaxies with proper motion that are not receding (i.e., Andromeda).

The reason that space does not appear to be expanding within galaxies is gravity is the overriding factor and keeps things more or less at the same distances from each other.

However, between galaxies gravity's affect is not enough to keep neighboring galaxies from receding with the expansion of space.

There is no origin or center to the universe. This seems contradictory on the surface as we tend to think of things in terms we can grasp, such as an expanding balloon.

The problem with that analogy is that your perspective includes an outside and an inside, whereas the universe has no outside. It is not expanding into anything and you can't take off in a straight line and reach the end of the universe, either.

If you could and did do that you would eventually pass the point of where you started, yet you would have still taken a straight line path because space is curved or warped - yet hard to wrap your head around.

Oh, and I wish you better luck with your heater. Brrrr... :-)

But you can have absolute zero "nothing" as your limits or boundary, isn't it?

You might think so, but you might be wrong... :-)

Interesting but how did they manage to measure such negative absolute temperature?

Where the findings accepted by critics and the science society? There should be a theoretical framework or evidence this could be done and repeated.

I've seen numerous reports on this subject, some from scholarly sources, but I have not tried vetting this myself.

Could be a reversal. All particles in space, as an energy could exist in two opposing reversal, by first law energy can not be created or destroyed. Give us an insight of say E_converging-E_diverging= 0, suspended in perfection or nothingness

Existence could be describe as diverging/emitting Energy we can always expect there should be an opposite converging Energy forms to this as per first law and it's pretty exciting to find what it is and how did it come up such a process.

But even so that is true, it does not change the fact that there are limits (ground state of matter and space).

Einstein recognized this very well when he said, "The difference between stupidity and genius is that genius has its limits."

I agree.

Wow. So much for thermodynamics, then? Just to be sure we are talking negative Kelvin? I have no idea what they mean by "quantum gas", or how they get this as cold as within a few thousandths of 0K to begin with.

Thanks AH 41 "....you would eventually pass the point of where you started..."

That's feasible. Light bends due to gravity. It would curve around the mass of universe.

In fact, with a telescope powerful enough you would eventually see the back of your neck.

I accept my theory above might be flawed, because boilerwise I still have problems. If all else fails, I guess I'll have to read the instructions.

Contraction? Lets look at E=MC², if in a black hole the mass increases? Then so should its energy increase, as the speed of light is constant, so if we think of a black hole as an energy vacuum? Drawing that energy from surrounding mass, a galaxy, then what is relatively going to happen? Is that energy vacuum related to gravity?

So let's speculate, gravity is ripping energy out of the nearby planetary systems, and those systems are pulling energy from the outer system in a cascading flow? The effect being that the black hole will be slowly satisfied thereby reducing its effect, and the surrounding mass losing its energy losses its mass also? Size and gravitational effect remains relative?

If this speculation is correct? And the mass of galaxies are contracting and black holes fading, then, there are some relative things to be noticed. Galaxies will appear to be moving apart, and photons leaving a galaxy may relatively appear different? When it reaches a galaxy of smaller overall mass?

I have no qualification on this subject, its all pure speculation.

Regards JD

Thanks for all the great input. I appreciate your insights, comments and criticisms.

I really enjoyed reading through some of the tangents that people explored.

I had no thought this discussion would generate even a dozen responses, so I'm amazed it's gotten over 50.

Again, thanks.