# Can someone please explain galaxies moving 5 times light speed and

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how relativity which explicitly says that nothing with mass can travel faster than the speed of light predicts something with the mass of an entire galaxy moving faster than the speed of light is predicted by relativity which forbids this?

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Posted (edited)

Ok I'm no scientist and someone more qualified than me will surely give a better answer, but, in layman terms, the galaxies aren't actually moving faster than light. It's not the galaxies moving but the space between them, giving the appearance that the galaxies are moving faster than light.

Edited by Curious layman

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12 minutes ago, Angelo said:

how relativity which explicitly says that nothing with mass can travel faster than the speed of light predicts something with the mass of an entire galaxy moving faster than the speed of light is predicted by relativity which forbids this?

Space/distance is created between galaxies a certain minimum distance apart, so in the galaxy frame they are moving their normal speed. Space can expand as fast as it likes without violating Relativity.

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Posted (edited)

Telescopes, like Hubble, record photography of cosmic objects, and distant galaxies.

To get good quality picture from distant object, telescope must be recording object with very long exposure.

"This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time. "

Long-time exposure photography

Photons are emitted with inverse-square law, so their quantity per area drops with distance. Read inverse-square law wikipedia article if you are not familiar with it.

So, if you know that object should emit specific amount of energy, you can estimate distance to it, by reversing inverse-square law.

This method is called "Standard candles". https://en.wikipedia.org/wiki/Cosmic_distance_ladder

Scientists found that distant objects are redshifted. Some of them extremely redshifted. This is article you must read:

The older galaxy you see, the more distant it is, and the higher redshift. It leaded to conclusion of that Universe is expanding.

List of galaxies with some very high redshift (z value):

For example this galaxy found in 2016:

"GN-z11 is a high-redshift galaxy found in the constellation Ursa Major. GN-z11 is currently the oldest and most distant known galaxy in the observable universe.[4] GN-z11 has a spectroscopic redshift of z = 11.09, which corresponds to a proper distance of approximately 32 billion light-years (9.8 billion parsecs).[5][note 1]"

To measure redshift, scientists are measuring shift of spectral lines emitted by well-known elements like Hydrogen or Helium, with assumption that they never changed in the past history of the Universe.

Again, if you're not familiar with it, you must read articles about spectral lines, emission spectrum, blackbody radiation etc.

ps. Yes, in computer games and simulations, programmers are constructing them in such way, that entities living inside are reaching internal "wall" which is impossible to be transcended..

Edited by Sensei

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37 minutes ago, Angelo said:

how relativity which explicitly says that nothing with mass can travel faster than the speed of light predicts something with the mass of an entire galaxy moving faster than the speed of light is predicted by relativity which forbids this?

Special relativity says that two things cannot move relative to one another faster than the speed of light. This only applies locally in the absence of gravity and curved spacetime.

General relativity is the basis of the big bang model; that the universe is expanding. This is expansion is a scaling effect, so distances get multiplied by some factor in every unit of time.

For example, consider a number of galaxies separated by the same distance (far enough apart that the expansion of space is significant and the same between all of them).

At time 0, they are 1 unit apart:
A.B.C.D.E.F

After some time they are 2 units apart:
A..B..C..D..E..F

After the same time again, they are 3 units apart:
A...B...C...D...E...F

And so on:
A....B....C....D....E....F

Now, if we look at the distance between B and C, for example, it increases by 1 at every time step. But the distance between B and D increases by 2 at every step. So the distance between B and D is increasing twice as fast as the distance between B and C; i.e. the speed of separation is twice as great.

Choose any pairs of galaxies and you will see that apparent the speed of separation is proportional to the distance between them. Take two objects far enough apart and the speed of separation will be greater than the sped of light.

More here: https://arxiv.org/abs/astro-ph/0310808

Quote

We show that we can observe galaxies that have, and always have had, recession velocities greater than the speed of light. We explain why this does not violate special relativity and we link these concepts to observational tests.

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50 minutes ago, StringJunky said:

Space/distance is created between galaxies a certain minimum distance apart, so in the galaxy frame they are moving their normal speed. Space can expand as fast as it likes without violating Relativity.

Space is a constant, the changes come from the mass moving thru space.

28 minutes ago, Strange said:

Special relativity says that two things cannot move relative to one another faster than the speed of light. This only applies locally in the absence of gravity and curved spacetime.

General relativity is the basis of the big bang model; that the universe is expanding. This is expansion is a scaling effect, so distances get multiplied by some factor in every unit of time.

For example, consider a number of galaxies separated by the same distance (far enough apart that the expansion of space is significant and the same between all of them).

At time 0, they are 1 unit apart:
A.B.C.D.E.F

After some time they are 2 units apart:
A..B..C..D..E..F

After the same time again, they are 3 units apart:
A...B...C...D...E...F

And so on:
A....B....C....D....E....F

Now, if we look at the distance between B and C, for example, it increases by 1 at every time step. But the distance between B and D increases by 2 at every step. So the distance between B and D is increasing twice as fast as the distance between B and C; i.e. the speed of separation is twice as great.

Choose any pairs of galaxies and you will see that apparent the speed of separation is proportional to the distance between them. Take two objects far enough apart and the speed of separation will be greater than the sped of light.

More here: https://arxiv.org/abs/astro-ph/0310808

There is no absence of gravity where mass is concerned

37 minutes ago, Sensei said:

Telescopes, like Hubble, record photography of cosmic objects, and distant galaxies.

To get good quality picture from distant object, telescope must be recording object with very long exposure.

"This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time. "

Long-time exposure photography

Photons are emitted with inverse-square law, so their quantity per area drops with distance. Read inverse-square law wikipedia article if you are not familiar with it.

So, if you know that object should emit specific amount of energy, you can estimate distance to it, by reversing inverse-square law.

This method is called "Standard candles". https://en.wikipedia.org/wiki/Cosmic_distance_ladder

Scientists found that distant objects are redshifted. Some of them extremely redshifted. This is article you must read:

The older galaxy you see, the more distant it is, and the higher redshift. It leaded to conclusion of that Universe is expanding.

List of galaxies with some very high redshift (z value):

For example this galaxy found in 2016:

"GN-z11 is a high-redshift galaxy found in the constellation Ursa Major. GN-z11 is currently the oldest and most distant known galaxy in the observable universe.[4] GN-z11 has a spectroscopic redshift of z = 11.09, which corresponds to a proper distance of approximately 32 billion light-years (9.8 billion parsecs).[5][note 1]"

To measure redshift, scientists are measuring shift of spectral lines emitted by well-known elements like Hydrogen or Helium, with assumption that they never changed in the past history of the Universe.

Again, if you're not familiar with it, you must read articles about spectral lines, emission spectrum, blackbody radiation etc.

ps. Yes, in computer games and simulations, programmers are constructing them in such way, that entities living inside are reaching internal "wall" which is impossible to be transcended..

All photons examined were emitted form stars that have mass.  So the mass is the relevant object not the emitted photon

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4 minutes ago, Angelo said:

Space is a constant, the changes come from the mass moving thru space.

There is no absence of gravity where mass is concerned

All photons examined were emitted form stars that have mass.  So the mass is the relevant object not the emitted photon

It is very disingenuous to ask a question then assert the answers are wrong.

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Posted (edited)
21 minutes ago, Angelo said:

All photons examined were emitted form stars that have mass.  So the mass is the relevant object not the emitted photon

Photons are practically the only thing that you, and scientists, see and are able to measure their properties and quantities. Have you been on the Moon, Mars or Sun? No. You just saw photons from them emitted or reflected. Measurement of mass of the Moon, Mars, or Sun, is done by observation how other cosmic objects in neighborhood reacts, and reversing Newton's law of universal gravitation.

Apart from photons there is very little amount of neutrinos (they are used as indicators of supernova explosions).

Apart from photons and neutrinos, there are cosmic rays.

So, you (and scientists) learn what material is by observation of photons emitted by that material (spectral emission and absorption lines).

Edited by Sensei

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14 minutes ago, Angelo said:

Space is a constant, the changes come from the mass moving thru space.

Space is not a constant. It is observer dependent. And can be affected by the presence of mass or energy.

Quote

There is no absence of gravity where mass is concerned

Who said anything about the absence of gravity?

16 minutes ago, Angelo said:

All photons examined were emitted form stars that have mass.  So the mass is the relevant object not the emitted photon

The photons tell us about the stars that emitted them: their composition, their brightness, their relative speed, etc. All of this can tell us about the universe and how it is expanding.

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Posted (edited)
5 minutes ago, Sensei said:

Apart from photons and neutrinos, there are cosmic rays.

Good point! And I think we also may add gravitational waves as evidence that current models have predictive power.

Edited by Ghideon

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1 minute ago, Ghideon said:

Good point! And I think we also may add gravitational waves as evidence that current models have predictive power.

I think that the same results as "gravitational waves" (bending of spacetime curvature) would have burst of electric neutral particles, extremely weakly (or none) interacting with ordinary matter, interacting only gravitationally..

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3 hours ago, Angelo said:

Space is a constant, the changes come from the mass moving thru space.

Do you have any evidence to support that, or does that just seem right to you?

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In its simplest interpretation, Angelo, light, or electromagnetic radiation, is a wave.
Consider a wave, positive and negative undulations of the Y value along the X axis, a sine wave if you will.
The peaks and troughs of this wave are regularly spaced, according to the frequency of the electromagnetic radiation.

Now the separation between objects where the gravitational binding is too weak to overcome 'expansion' is growing; In effect, for largely separated objects, think galaxies and clusters of them, the universe is scaling upwards.

Light that was emitted by these distant galaxies, was emitted long ago ( because of the finite speed of light ) and, as a result, the separation between the emitter galaxy ( long ago ) and the receiver ( us, now ) has grown according to this expansion or scaling.
This has the effect of 'stretching' along the X axis the distances between peaks and troughs of the light, making the wavelength longer.
We call this effect red-shifting, and it is proportional to distance.

Please ask about any concepts you don't understand, I, or others, will try to explain to the best of our abilities.

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Here is an interesting side note recessive velocity is based upon Hubble's law. The greater the seperation distance the greater the recessive velocity the formula is

$V_{recessive}=H_OD$

So beyond Hubble horizon based on that formula the galaxies appear to be separating at greater than c. However that is an Apparent velocity and not a true velocity. In point of fact those galaxies move at the same speeds as our own Milky way.

This brings a further side note expansion being described as greater than c uses the same seperation distance relationship.

However per Mpc in every location the expansion rate is only roughly 70 Km/Mpc/sec this rate is actually decreasing even though the expansion rate based on the seperation distance to our cosmological event horizon is accelerating.

So there is no violation of GR as recessive velocity is an apparent velocity and not a true velocity.

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Further to Mordred's point about apparent velocities and the effect of scaling on them...

I can easily move the bright dot of a laser faster than the speed of light across the surface of the moon, by moving the laser relatively slowly here on earth.

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Posted (edited)
On ‎1‎/‎7‎/‎2020 at 6:56 PM, Bufofrog said:

Do you have any evidence to support that, or does that just seem right to you?

Do you have any evidence about the speed of distant galaxies that eludes everyone else?

See anyone can say anything if they choose including those that say there is no universe just Gods hard drive.

Why do you tolerate people telling you that you do not really exist?

PS. I do not believe in Gods hard drive, that belief goes to great physicist that say they do not believe in God, then say God made everything

Is being that silly fun

On ‎1‎/‎7‎/‎2020 at 10:46 PM, MigL said:

Further to Mordred's point about apparent velocities and the effect of scaling on them...

I can easily move the bright dot of a laser faster than the speed of light across the surface of the moon, by moving the laser relatively slowly here on earth.

Funny how Einstein claimed that nothing was moving, that the universe was a static bubble

Edited by Angelo

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Posted (edited)
42 minutes ago, Angelo said:

Do you have any evidence about the speed of distant galaxies that eludes everyone else?

See anyone can say anything if they choose including those that say there is no universe just Gods hard drive.

Why do you tolerate people telling you that you do not really exist?

PS. I do not believe in Gods hard drive, that belief goes to great physicist that say they do not believe in God, then say God made everything

Is being that silly fun

Funny how Einstein claimed that nothing was moving, that the universe was a static bubble

Which, he conceded, was wrong. Einstein evolved with evidence. You could do the same.

Edited by StringJunky

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Posted (edited)

Expansion has been well established since Hubble. The evidence goes beyond merely noting recessive velocity of Galaxies but also includes thermodynamic evidence. The universe cools down as expansion occurs. The CMB itself wouldn't exist without expansion.

Science doesn't stop when Einstein died...

Edited by Mordred

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2 hours ago, Angelo said:

Do you have any evidence about the speed of distant galaxies that eludes everyone else?

See anyone can say anything if they choose including those that say there is no universe just Gods hard drive.

Why do you tolerate people telling you that you do not really exist?

PS. I do not believe in Gods hard drive, that belief goes to great physicist that say they do not believe in God, then say God made everything

Is being that silly fun

Funny how Einstein claimed that nothing was moving, that the universe was a static bubble

Your only questions are sarcastic and unhelpful. Your assertions have mostly been wrong, and have been pointed out to you, but you've chosen to ignore them. You're rejecting explanations without reason, simply because they don't seem intuitive to you. This isn't personal, it isn't about you. It's your approach to learning that's causing a problem in discussions.

I have to ask, is there any way to reason with you on this subject, or is your incredulity always going to be an impassable obstacle? How can we turn this discussion into a meaningful one? Several people have tried explaining what mainstream science says on this subject, but it's hard to have a conversation with you when half the effort is spent trying to get your fingers out of your ears.

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On 1/7/2020 at 10:30 PM, Sensei said:

Photons are practically the only thing that you, and scientists, see and are able to measure their properties and quantities. Have you been on the Moon, Mars or Sun? No. You just saw photons from them emitted or reflected. Measurement of mass of the Moon, Mars, or Sun, is done by observation how other cosmic objects in neighborhood reacts, and reversing Newton's law of universal gravitation.

Apart from photons there is very little amount of neutrinos (they are used as indicators of supernova explosions).

Apart from photons and neutrinos, there are cosmic rays.

So, you (and scientists) learn what material is by observation of photons emitted by that material (spectral emission and absorption lines).

Do you mean that all the information we get from the universe is reaching us with velocity C ?

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3 hours ago, Angelo said:

Funny how Einstein claimed that nothing was moving, that the universe was a static bubble

Which was based on the evidence and science available at the time. IOQW, he did not predict something that had no basis in evidence or theory, which is how science is supposed to proceed. (If you're making predictions any other way, you aren't doing science)

10 minutes ago, michel123456 said:

Do you mean that all the information we get from the universe is reaching us with velocity C ?

Some gets to us slower than c.

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15 minutes ago, michel123456 said:

Do you mean that all the information we get from the universe is reaching us with velocity C ?

He's saying all the data we receive is through photons.

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11 hours ago, Phi for All said:

Your only questions are sarcastic and unhelpful. Your assertions have mostly been wrong, and have been pointed out to you, but you've chosen to ignore them. You're rejecting explanations without reason, simply because they don't seem intuitive to you. This isn't personal, it isn't about you. It's your approach to learning that's causing a problem in discussions.

I have to ask, is there any way to reason with you on this subject, or is your incredulity always going to be an impassable obstacle? How can we turn this discussion into a meaningful one? Several people have tried explaining what mainstream science says on this subject, but it's hard to have a conversation with you when half the effort is spent trying to get your fingers out of your ears.

My assertion is that no one knows, do you know?

10 hours ago, StringJunky said:

He's saying all the data we receive is through photons.

All the data I just received from you is 0 and 1's.  They are irrelevant as it is your sentence in English that matters

10 hours ago, michel123456 said:

Do you mean that all the information we get from the universe is reaching us with velocity C ?

Unknown

Edited by Angelo

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2 hours ago, Angelo said:

All the data I just received from you is 0 and 1's.  They are irrelevant as it is your sentence in English that matters

You received Phi's reply via light emitted by the TFT screen of your computer.
No 1s and 0s came pouring out of your screen.
And unless you're blind, I don't think your computer 'reads' Phi's sentences to you.

And what does any of that have to do with discrepancies in the values obtained for Hubble's constant using two differing measurement methods  ?

The link you used to back up your opinions is lacking in relevance.

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46 minutes ago, MigL said:

The link you used to back up your opinions is lacking in relevance.

It's also evident the OP isn't aware the discrepancy is within a 6 km/Mpc/sec error margin. Both studies show the universe is expanding.

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