How do we know the real size of the space in the Universe? Is it finite or infinite?

[Dandav]

It's the time to unleash the observation and the Universe size from the current theory / expansion limitation.

WAMP Observation is very Clear:

On 12/10/2024 at 8:43 AM, Dandav said:

https://map.gsfc.nasa.gov/universe/uni_matter.html

WMAP determined that the universe is flat, from which it follows that the mean energy density in the universe is equal to the critical density (within a 0.5% margin of error). This is equivalent to a mass density of 9.9 x 10^-30 g/cm³, which is equivalent to only 5.9 protons per cubic meter.

Planck mission is very clear:

On 12/10/2024 at 8:43 AM, Dandav said:

https://en.wikipedia.org/wiki/Shape_of_the_universe

Final results of the Planck mission, released in 2018, show the cosmological curvature parameter, 1 − Ω = Ω_K = −Kc²/a²H², to be 0.0007±0.0019, consistent with a flat universe

The following calculation is very clear:

On 12/5/2024 at 1:26 AM, OceanBreeze said:

So, the density parameter, Ω = (8.369E-27 kg / cubic meter) / (8.81E-27 kg / cubic meter) ~ 0.95

That is very close to 1 considering my rough calculation and rounding off.

The observational evidence suggests that the observable universe is spatially flat with ZERO curvature:

On 12/10/2024 at 8:43 AM, Dandav said:

As of 2024, current observational evidence suggests that the observable universe is spatially flat

It's time to accept the simple understanding that the real universe is most likely infinite, or at least it doesn't have an edge

On 11/22/2024 at 8:55 AM, Dandav said:

Universe with zero curvature 

In a universe with zero curvature, the local geometry is flat. The most familiar such global structure is that of Euclidean space, which is infinite in extent.

 

On 11/29/2024 at 10:02 PM, Dandav said:

https://www.britannica.com/video/universe/-203957

On 11/26/2024 at 9:14 PM, Dandav said:

Space is most likely infinite, or at least it doesn't have an edge

The following understanding about the Global geometry universe is real.

On 11/24/2024 at 8:20 AM, Dandav said:

https://en.wikipedia.org/wiki/Shape_of_the_universe

Local geometry: This relates to the curvature of the universe, primarily concerning what we can observe.

Global geometry: This pertains to the universe's overall shape and structure.

Therefore, we have to agree that the Global geometry universe is most likely infinite, it doesn't have an edge (or at least it's volume is several millions bigger than the observable / local geomerty universe).

This understanding is based on a pure observation!

Edited December 12 by Dandav

[Dandav]

For those of us that are still wonder what does it mean to have Zero curvature I would like to offer the following question/explanation:

Is there any possibility to observe the whole curvature' Earth surface (or Earth's circumference) but verify that it is flat with Zero curvature?

If you think that it is feasible , then please explain how it could really work.

If you agree that it is impossible, then you should also agree that with zero curvature we can only observe a very tinny segment of the curvature' Earth surface.

As an example, we can use the Ant point of view for zero curvature.

This Ant can only observe a very tinny segment of the curvature' Earth surface

Hence, whenever we observe Zero curvature in a curvature' object, then it means that we only observe a tinny segment of this object.

However, there is a possibility that this object is flat without any curvature.

In the same token, if we believe that the entire universe has a curvature, but we clearly can't observe any sort of curvature in our local / observable universe, then it means that the entire universe (global geometry universe) is significantly bigger than the observable universe.

However, there is a possibility that there is no curvature in the global geometry universe and therefore it must be infinite in its size.

I hope that by now we fully understand that the real meaning of Zero curvature is that the global geometry Universe (the whole real Universe) is flat and therefore it is infinite or at least significantly bigger than our tinny size segment that is called observable universe.

Once we agree with that, then it’s the time to unleash the redshift and CMBR from the severe distance limitation due to the current expansion theory.

Any objection?

 

Edited December 14 by Dandav

[engcat]

On 12/4/2024 at 6:26 PM, OceanBreeze said:

going to take the liberty of calling the density parameter close enough to 1 to claim a flat universe with zero curvature that is expanding. Notice this calculation says nothing about the acceleration of that expansion; the accelerated expansion of the universe was determined through observations of distant supernovae and redshift of distant galaxies. Initially it was not mathematically calculated and came as quite a surprise to scientists studying the cosmos.

No doubt there are even more surprises in store as the question about the ultimate fate of the universe is still unanswered.

 

 

Flat refers to G in Einsteins equation, and G factor is about flat or warrped spacetime, locally. Here, the question is not about G but about Lambda, whether spacetime is static, contracting or expanding. Just a clarification on terminology.

Since the time Einstein introduced the cosmological constant Lambda, it was discovered that spacetime is actually expanding and not static as Eistein thought. It is not contracting either. Whence the hypothesis about some dark energy that we cannot see but acts to expand the spacetime. In this world that constant is less than one for the purposes of Einstein's equation because spacetime is expanding according to observation.

Can spacetime be flat and expanding as you suggest? Yes, only locally, roughly, it can be flat in areas with no mass in vacuum in accordance with G matrices, and it can be expanding in accordance with Lambda constant and observation.

Edited December 14 by engcat

[OceanBreeze]

2 hours ago, engcat said:

 

Flat refers to G in Einsteins equation, and G factor is about flat or warrped spacetime, locally. Here, the question is not about G but about Lambda, whether spacetime is static, contracting or expanding. Just a clarification on terminology.

Since the time Einstein introduced the cosmological constant Lambda, it was discovered that spacetime is actually expanding and not static as Eistein thought. It is not contracting either. Whence the hypothesis about some dark energy that we cannot see but acts to expand the spacetime. In this world that constant is less than one for the purposes of Einstein's equation because spacetime is expanding according to observation.

Can spacetime be flat and expanding as you suggest? Yes, only locally, roughly, it can be flat in areas with no mass in vacuum in accordance with G matrices, and it can be expanding in accordance with Lambda constant and observation.

Whenever I mention the "universe" I am referring to the only universe we know about, the observable universe. Everything I say about flatness, expansion or whatever, it is only about locally, as talking about a "global" universe is not falsifiable and therefore not scientific.

The universe that we observe is flat, meaning it has Euclidean geometry. We also observe this universe is expanding and the expansion is accelerating.

Flatness has only to do with local geometry and it says nothing about the topology. I am not flat, and my house is not flat! The topology is 3D and as far as we know the observable universe is a sphere roughly 50 billion light years in radius.

Also, a flat geometry doesn't imply the universe is infinite in extent. A piece of A4 paper has flat geometry but it has dimensions of 210 x 297 mm.

All of the above is just for clarification. There is too much confusion about what a flat geometry means and what the difference is between local geometry and topology. I know everyone will not agree with what I wrote, but I believe it is correct, while inviting discussion.

[Dandav]

9 hours ago, OceanBreeze said:

Flatness has only to do with local geometry and it says nothing about the topology. 

How can we offer any sort of solution / theory for a universe that its local geometry is clear but its total topology / size is unknow?

Two examples:

1. Ant observable Universe - Are you willing to accept Ant' explanations for how her observable universe works while she has no clue about the topology of the entire Earth?

2. Engine for Plastic Toy airplane VS Jumbo jet airplane - Do you think that the same engine that works for a toy airplane can also work for a Jumbo jet airplane?

Sorry, whenever we offer a solution for something, our first obligation is to verify its real size and & topology.

9 hours ago, OceanBreeze said:

We also observe this universe is expanding and the expansion is accelerating.

Do we observe that the space in the universe is expanding or we only observe that the galaxies in this universe are expanding?

Can we really measure the expansion in the universe space regardless of the motion of the galaxies?

If the answer is no, then do you confirm that the idea that the universe' space is expanding had been selected just in order to explain the expansion / motion of the galaxies?

Therefore, can we agree that the correct message should be:

"We observe that the galaxies in the observable universe are expanding and their expansion is accelerating as they are located further away from us, but we can't observe if the universe space itself is expanding even by one pico mm per billion year."

9 hours ago, OceanBreeze said:

Also, a flat geometry doesn't imply the universe is infinite in extent. A piece of A4 paper has flat geometry but it has dimensions of 210 x 297 mm.

This kind of flat geometry can't explain why the CMBR is so smooth and uniform from all directions and why it keeps its black body radiation.

I would like to remind you that the main idea in the current expansion theory is that the space itself is expanding and therefore in any location that we would be in the observable universe we should get the same smooth and uniform black body CMBR.

A flat universe can't technically meet this requirement.

Therefore, by definition a flat observable universe is a severe contradiction to the expansion theory.

Actually, it was expected that at the moment that we have discovered that there is no curvature in the observable universe we had to abandon the expansion theory and verify what could be the real size of the universe.

Therefore, it is very clear that the current expansion theory can't work in a flat universe even if we ignore the entire real universe size.

9 hours ago, OceanBreeze said:

The topology is 3D and as far as we know the observable universe is a sphere roughly 50 billion light years in radius.

How do we know for sure that the radius of the observable universe is 50 Billion years?

Is it based on the expansion theory?

However, we have just verified that the expansion theory can't work in a flat observable universe.

Therefore, it is a severe mistake to base the radius of the observable universe on a wrong theory.

Please, is there any possibility to unleash the radius and the data in the CMBR including its redshift from the current expansion limitation?

Edited December 14 by Dandav

[Dandav]

The spectral distortion in the cosmic microwave background

Please look at the following spectral distortion in the cosmic microwave background (CMB) black body which is due severe redshift spectrum

https://en.wikipedia.org/wiki/Cosmic_microwave_background_spectral_distortions#/media/File:Spectral_distortions_in_the_early_universe_new.gif

The spectral distortion in the cosmic microwave background (CMB) looks different depending on the moment in the universe's history where this black body was modified. At very early times where , any injection of energy emerges as a temperature shift in the black body.

It is also stated:

https://en.wikipedia.org/wiki/Cosmic_microwave_background_spectral_distortions#Experimental_and_observational_challenges

at redshifts , several mechanisms, both standard and non-standard, can modify the CMB spectrum and introduce departures from a blackbody spectrum.

The current best observational limits set in the 1990s by COBE-satellite/FIRAS-instrument (COBE/FIRAS) are  and  at 95% confidence level. Within ΛCDM we expect  and , signals that have come into reach of current-day technology (see § Experimental and observational challenges). 

At redshifts between  and , efficient energy exchange through Compton scattering continues to establish kinetic equilibrium between matter and radiation, but photon number changing processes stop being efficient.

Therefore, we detect wide redshift spectrum (from about 2*10^6) in the CMBR which is responsible for the spectral distortion.

Once we unleash the CMBR from the tinny observable universe size and agree that the real universe could be infinite (or at least significantly bigger than the observable universe), then we can understand that this wide redshift spectrum in the CMBR comes from different distances in that unknown global geometry universe.

We already know that as the galaxy is located further away from our location, its redshift should be higher.

The highest redshift of a galaxy that we have detected so far was about 13.

So just think how far a galaxy should be located if we detect its photon (in the CMBR) with a redshift of 10^6 or even 10^3. 

I was expecting to detect this kind of high redshift in the CMBR:

On 11/28/2024 at 9:14 AM, Dandav said:

Actually if my understanding is correct, and the CMBR is based on the photons that comes from the Infinite galaxies in the Infinite Global geometry Universe, then those photons should come at a very high redshift.

Therefore, I wonder if there is any possibility for us to isolate each photon and detect its redshift in order to estimate the location of its source.

Hence, the discovery that the photons in the CMBR carry high redshift spectrum is a clear indication that those photons are coming from very far distances.

Just a brief calculation (for a smooth and flat universe):

if we claim that a redshift of 13 is equivalent to a distance of 13 BLY, than technically a redshift of 10^6 represents a distance of:

13BLY * 10^6 / 13 = 10^6 BLY.

Can we consider this kind of global geometry universe as infinite or close to infinite universe?

 

Edited December 15 by Dandav

[engcat]

19 hours ago, Dandav said:

 

Therefore, can we agree that the correct message should be:

"We observe that the galaxies in the observable universe are expanding and their expansion is accelerating as they are located further away from us, but we can't observe if the universe space itself is expanding even by one pico mm per billion year."

 

 

No, the galaxaies are not "expanding."  Galaxies are "moving away" from us.  That Doppler effect is Slipher's observation. And yes they move away faster if they are farther away.  

The basis for the math of distances is the inverse square law to the brightness of light. So, we get non linear, progressively larger distances, or accelerated motion away from earth. The motion is uniform and universal. Hubbell concluded based on those findings that spacetime is expanding. Since this observed motion is based on inverse square law of distances, math can include a cosmological constant Lambda to explain it, and that is consistent with Einstein's tensor equation.

An alternative view is that there exists dark energy which is responsible for the motion of galaxies which Slipher observed, away from the Earth. This would delete the Lambda cosmological constant, and would introduce some other "dark energy" matrices in the formula.  Spacetime then would not be stretching (expanding).   However, no one observed any matter or energy in the universe that is responsible for uniform and universal motion away from anything. So this hypothesis about dark energy is inconsistent with observation. Even though acceleration and gravity are indistinguishable in Relativity under Einstein's tensor equations.

In there lies the problem, there is something within spacetime that distinguishes some accelerations from curvature (gravity). Hence, Lambda factor for spacetime itself, separate from G factor which is the curvature (gravity).

 

 

Edited December 15 by engcat

[OceanBreeze]

On 12/15/2024 at 12:31 PM, Dandav said:

Hence, the discovery that the photons in the CMBR carry high redshift spectrum is a clear indication that those photons are coming from very far distances.

Just a brief calculation (for a smooth and flat universe):

if we claim that a redshift of 13 is equivalent to a distance of 13 BLY, than technically a redshift of 10^6 represents a distance of:

13BLY * 10^6 / 13 = 10^6 BLY.

Can we consider this kind of global geometry universe as infinite or close to infinite universe?

 

You have this completely wrong!

First thing to understand is that all the photons in the CMB come from a time when the universe was very young; at the time of the surface of last scattering, about 380,000 years after the  Big Bang nucleosynthesis.

The vast majority of the photons in the CMB have a redshift of ~ 1100 but there are some with much higher redshifts; as high as 10E6. This does not mean these photons come from some great distance away, and it certainly does not mean they come from distant galaxies. At the time these photons were scattering within the CMB, there were no galaxies!

These photons became highly redshifted due to collisions with other particles, mainly electrons, in the dense particle soup that existed in the very early universe, as depicted in this diagram:

 

The collisions, known as Compton scattering, transfer energy away from the photons. Less energetic photons will appear to be redshifted with longer wavelengths.

I am not amazed that such highly redshifted photons still exist in the CMB, but I am amazed that we have developed instruments sensitive enough to detect them.

Returning to the subject of galaxies, which has nothing to do with redshift in the CMB:

The galaxy with the highest observed redshift today is  JADES-GS-z14-0; with a redshift of 14.32, it is now approximately 33.5 Billion Light years distant from Earth. This great distance is still well within the estimated radius of the observable universe (~50 Billion Light Years).

There are no galaxies with redshifts anywhere near 10^6 making your calculation “not even wrong”, it is ridiculous!

 

 

 

 

 

[OceanBreeze]

18 hours ago, engcat said:

 

No, the galaxaies are not "expanding."  Galaxies are "moving away" from us.  That Doppler effect is Slipher's observation. And yes they move away faster if they are farther away.  

The basis for the math of distances is the inverse square law to the brightness of light. So, we get non linear, progressively larger distances, or accelerated motion away from earth. The motion is uniform and universal. Hubbell concluded based on those findings that spacetime is expanding. Since this observed motion is based on inverse square law of distances, math can include a cosmological constant Lambda to explain it, and that is consistent with Einstein's tensor equation.

 

OK

 

18 hours ago, engcat said:

An alternative view is that there exists dark energy which is responsible for the motion of galaxies which Slipher observed, away from the Earth. This would delete the Lambda cosmological constant, and would introduce some other "dark energy" matrices in the formula.  Spacetime then would not be stretching (expanding).   However, no one observed any matter or energy in the universe that is responsible for uniform and universal motion away from anything. So this hypothesis about dark energy is inconsistent with observation. Even though acceleration and gravity are indistinguishable in Relativity under Einstein's tensor equations.

In there lies the problem, there is something within spacetime that distinguishes some accelerations from curvature (gravity). Hence, Lambda factor for spacetime itself, separate from G factor which is the curvature (gravity).

 

Deleting Lambda and replacing it with Dark Energy does not stop the expansion of space! All that does is provide a different explanation for what we observe. Space IS expanding, by observation, and the expansion is accelerating, also by observation.

We have no direct observations of Dark Matter or Dark Energy but we do observe the gravitational effects. Dark Matter is thought to be responsible for the observed spin of galaxies. There is not enough ordinary baryonic matter (that interacts with light) present in galaxies to account for the rotational (tangential) velocity of matter located at the outer edge of the spirals. It is thought Dark Matter forms a halo around galaxies and this provides enough additional gravity to account for galactic spin.

The expansion of space that we observe is thought to be caused by Dark Energy, which is even stranger than Dark Matter because the energy density of Dark Energy remains constant, even as the volume of the universe increases. One explanation is, as the universe expands, it pulls on the DE with negative pressure, which does work on the DE, and according to work=energy, this constantly increases the amount of DE, keeping the DE density constant. These explanations are all debatable but what is NOT debatable is the fact the universe is expanding and the expansion is accelerating.

[Dandav]

On 12/16/2024 at 9:18 AM, OceanBreeze said:

First thing to understand is that all the photons in the CMB come from a time when the universe was very young

 How do we know that this idea is correct?

In the first message about the CMBR it is stated:

https://en.wikipedia.org/wiki/Cosmic_microwave_background

The cosmic microwave background (CMB, CMBR), or relic radiation, is microwave radiation that fills all space in the observable universe. 

It is also stated:

Quickly after the recombination epoch, the rapid expansion of the universe caused the plasma to cool down and these fluctuations are "frozen into" the CMB maps we observe today.

However, Photons cross the space at the speed of light 

https://en.wikipedia.org/wiki/Photon

Photons are massless particles that can move no faster than the speed of light measured in vacuum. The photon belongs to the class of boson particles.

The modern photon concept originated during the first two decades of the 20th century with the work of Albert Einstein, who built upon the research of Max Planck.

Therefore, don't you agree that it is a severe mistake to compare the photons to some sort of a frozen dust that fills the space?

Theoretically, if the observable universe was fully curvature, we could claim that photons orbit in some sort of cycles in this limited universe size and therefore, they would "stay" in the curvature universe for billions or even trillions of years

However, this is not the case as the observable universe is flat without any curvature.

It is very clear that any photon which had been created at any time in the past (at any era) must continue its motion to the infinity.

How can we even consider a possibility that photons from specific date (the surface of last scattering) would be so lucky to be frozen and fill all the open space.

Any idea how to freeze photons in space?

If it is feasible, why other photons from the universe history / Era can't also fill the space of the observable universe?

Do, you think Albert Einstein would confirm this idea of frozen photons in space?

[OceanBreeze]

20 hours ago, Dandav said:

 

Therefore, don't you agree that it is a severe mistake to compare the photons to some sort of a frozen dust that fills the space?

 

Yes, that is a big mistake and you are the only one making that mistake. Everyone else “hopefully” understands the individual photons that comprise the CMB are moving at the speed of light, and coming at us from all directions in space.

What is “frozen” is the pattern of fluctuations left on the photon field as they left the surface of last scattering. That is the familiar image we often see of the CMB:

As you can see the image is not entirely homogeneous, smooth and uniform, but contains some grainy structure caused by nonuniform temperatures across the spectrum.

The image we see was created at the time of last scattering, some 13+ Billion years ago. However, most of the photons which form that image were produced at a much earlier time in the evolution of the Universe. That is why some of the photons are extremely redshifted from Compton scattering.

This CMB radiation appears to come from a spherical surface all around us. The radius of that “shell” is the distance each photon has traveled since it left  the last scattering surface.  

We are able to see that image because our very sensitive radiotelescopes are looking back in time and seeing the photons as they were ~13 Billion years ago.

It is not much different than when you look at a star 100 light years away from you. You are seeing an image of that star created by photons that were emitted 100 years ago that are just reaching your eyes now, traveling at the speed of light. The star is most likely not where you are seeing it now! It might even have ceased to exist in the form that you are viewing it now,  but you have no way of knowing that at this moment in time.

The photons in the CMB that we see today have been traveling for 13+ billion years to reach our eyes now. During that time, the universe has expanded to be ~ 1000 times larger that it was at the time of last scattering. The stretching of space also stretched the photons so they are redshifted with a redshift of ~1000.  At 2.7 K, they are also about 1000 times cooler than when they left the surface of last scattering.

I hope that helps clear up your confusion about “frozen” photons!