universe may not be accelerating in expansion

[motlan]

Hubble explained he discovered other galaxies accelerating away from our milky way galaxy but could it be that those galaxies are being pulled away by the gravitational pull of other galaxies?  It is a fact that the Andromeda galaxy is pulled toward our galaxy by gravity and gravity accelerates the direction of the pull.  Perhaps it is not that space is spreading the galaxies away at an accelerated pace but rather other galaxies are pulled by an accelerated gravitational force towards each other away from us much like andromeda galaxy is being pulled towards our milky way galaxy.  just a thought.

[swansont]

How would you explain such an acceleration? How is it consistent with the mass distribution we observe, which is basically isotropic?

[motlan]

19 minutes ago, swansont said:

How would you explain such an acceleration? How is it consistent with the mass distribution we observe, which is basically isotropic?

why is andromeda galaxy pulled towards us by gravitational pull at an accelerated pace?  while other galaxies are moving away from us at an accelerated pace probably due to its accelerated gravitational pull by other distant galaxies.  Dark energy building up to accelerate the expansion of the universe does not cut it.  energy cannot be created or destroyed.  it will be diluted in time.

[MigL]

The energy fueling expansion acts very much like the Cosmological Constant in the original Einstein field equations of GR.
As a constant, of very small value/effect, it doesn't become apparent until the effects of gravity have decreased considerably with distance.
That distance, where the threshold is exceeded, happens to be in the order of galaxy cluster distances.
That means galaxies like the Milky Way and M31 ( in Andromeda ) can still be gravitationally bound, but our local group, and the surrounding others, are not.

[swansont]

9 hours ago, motlan said:

why is andromeda galaxy pulled towards us by gravitational pull at an accelerated pace? 

What is your evidence that it is?

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while other galaxies are moving away from us at an accelerated pace probably due to its accelerated gravitational pull by other distant galaxies. 

But those distant galaxies need even further distant galaxies to accelerate them, and they need more of them to make that happen. And those need galaxies beyond them, and so on, and so on.

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Dark energy building up to accelerate the expansion of the universe does not cut it. 

Dissatisfaction with the current model does not constitute evidence of your proposal.

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energy cannot be created or destroyed.  it will be diluted in time.

Let's focus on the current nonsense before getting to this nonsense.

[joigus]

10 hours ago, motlan said:

Dark energy building up to accelerate the expansion of the universe does not cut it.

Why?

[Halc]

13 hours ago, motlan said:

Hubble explained he discovered other galaxies accelerating away from our milky way galaxy

Hubble helped provide evidence for the expansion, but did not discover it.  He certainly didn't discover the acceleration of the expansion, which wasn't known for over 4 decades after his death.

 

could it be that those galaxies are being pulled away by the gravitational pull of other galaxies?  It is a fact that the Andromeda galaxy is pulled toward our galaxy by gravity and gravity accelerates the direction of the pull. Perhaps it is not that space is spreading the galaxies away at an accelerated pace but rather other galaxies are pulled by an accelerated gravitational force towards each other away from us much like andromeda galaxy is being pulled towards our milky way galaxy.  just a thought.

Yes, but that kind of motion (peculiar motion) is caused by local mass distribution, just like Earth's motion is largely effected by nearby masses, notably the sun. With peculiar motion, every change in momentum in one direction must be countered by some other opposite momentum change in the opposite direction. The peculiar motion of the Milky Way is actually more or less away from Andromeda, being largely influenced by the VIrgo supercluster, the Great Attractor, and ultimately the Shapley Attractor, all of which are vaguely in the same direction somewhat away from Andromeda.  That will of course change when Andromeda passes us and gets on the other side in its slow dance to eventually consume us.

None of this motion has anything to do with accelerated expansion of space.

Accleration is observed by noting that Hubble's constant (rate of change in proper distance as a function of comoving distance) is not constant, but has been increasing since a minimum was reached about have the age of the universe ago.  Before then it was considerably higher, and decelerating, mostly due to gravity predominating over dark energy during a time when the mass density of the universe was sufficiently high.

[motlan]

2 hours ago, Halc said:

Hubble helped provide evidence for the expansion, but did not discover it.  He certainly didn't discover the acceleration of the expansion, which wasn't known for over 4 decades after his death.

 

 

Yes, but that kind of motion (peculiar motion) is caused by local mass distribution, just like Earth's motion is largely effected by nearby masses, notably the sun. With peculiar motion, every change in momentum in one direction must be countered by some other opposite momentum change in the opposite direction. The peculiar motion of the Milky Way is actually more or less away from Andromeda, being largely influenced by the VIrgo supercluster, the Great Attractor, and ultimately the Shapley Attractor, all of which are vaguely in the same direction somewhat away from Andromeda.  That will of course change when Andromeda passes us and gets on the other side in its slow dance to eventually consume us.

None of this motion has anything to do with accelerated expansion of space.

Accleration is observed by noting that Hubble's constant (rate of change in proper distance as a function of comoving distance) is not constant, but has been increasing since a minimum was reached about have the age of the universe ago.  Before then it was considerably higher, and decelerating, mostly due to gravity predominating over dark energy during a time when the mass density of the universe was sufficiently high.

As of January 2018, measurements from multiple telescopes showed that the rate of expansion of the universe is different depending on where you look. The nearby universe (measured by the Hubble Space Telescope and Gaia space telescope) has a rate of expansion of 45.6 miles per second (73.5 kilometers per second) per megaparsec, while the more distant background universe (measured by the Planck telescope) is a bit slower, expanding at 41.6 miles per second (67 km per second) per megaparsec. A megaparsec is a million parsecs, or about 3.3 million light-years, so this is almost unimaginably fast. this confirms that it is the uneven distribution of gravitational pull by galaxies on galaxies situated in different regions of space.  I believe the universe is expanding at constant velocity.

[zapatos]

16 hours ago, motlan said:

Hubble explained he discovered other galaxies accelerating away from our milky way galaxy but could it be that those galaxies are being pulled away by the gravitational pull of other galaxies?  It is a fact that the Andromeda galaxy is pulled toward our galaxy by gravity and gravity accelerates the direction of the pull.  Perhaps it is not that space is spreading the galaxies away at an accelerated pace but rather other galaxies are pulled by an accelerated gravitational force towards each other away from us much like andromeda galaxy is being pulled towards our milky way galaxy.  just a thought.

How do you explain the fact that according to your hypothesis we would be right in the center of the universe? Dumb luck? God?

[motlan]

20 minutes ago, zapatos said:

How do you explain the fact that according to your hypothesis we would be right in the center of the universe? Dumb luck? God?

there is no dark energy being created to accelerate the expansion of the universe.  energy cannot be created.  they have no evidence of such energy.  the universe is expanding at constant velocity.  perhaps albert einstein perceived the cosmological constant correctly and predicts the universe will eventually collapse upon itself contracting spacetime.  I do not know the implications of this effect.  thus adhering to my reverse order mathematics for all physics equations.

[swansont]

56 minutes ago, motlan said:

As of January 2018, measurements from multiple telescopes showed that the rate of expansion of the universe is different depending on where you look. The nearby universe (measured by the Hubble Space Telescope and Gaia space telescope) has a rate of expansion of 45.6 miles per second (73.5 kilometers per second) per megaparsec, while the more distant background universe (measured by the Planck telescope) is a bit slower, expanding at 41.6 miles per second (67 km per second) per megaparsec. A megaparsec is a million parsecs, or about 3.3 million light-years, so this is almost unimaginably fast.  

When you quote from another site you should give the link. https://www.space.com/25179-hubble-constant.html

Passing off other peoples' work as your own is plagiarism, and improperly using other work without attribution is a copyright violation.

 

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this confirms that it is the uneven distribution of gravitational pull by galaxies on galaxies situated in different regions of space.  I believe the universe is expanding at constant velocity.

But the snippet you quoted makes a distinction based on distance, not direction. Where is the evidence that this is based on an "uneven distribution of gravitational pull"?

[zapatos]

49 minutes ago, motlan said:

there is no dark energy being created to accelerate the expansion of the universe.  energy cannot be created.  they have no evidence of such energy.  the universe is expanding at constant velocity.  perhaps albert einstein perceived the cosmological constant correctly and predicts the universe will eventually collapse upon itself contracting spacetime.  I do not know the implications of this effect.  thus adhering to my reverse order mathematics for all physics equations.

Nice dodge.

[MigL]

2 hours ago, motlan said:

As of January 2018, measurements from multiple telescopes showed that the rate of expansion of the universe is different depending on where you look. The nearby universe (measured by the Hubble Space Telescope and Gaia space telescope) has a rate of expansion of 45.6 miles per second (73.5 kilometers per second) per megaparsec, while the more distant background universe (measured by the Planck telescope) is a bit slower, expanding at 41.6 miles per second (67 km per second) per megaparsec.

Further to Swansont's comment about linking such postings, it is also customary to quote the error of the measurements.
If both measurements are +/- 5 km/sec , very likely when dealing with astronomical distances ( and possibly not quite standard candles ), then they are equivalent in the range of 68.5-72 km/sec.
They might not be different measurements after all.
 

[Bufofrog]

3 hours ago, motlan said:

As of January 2018, measurements from multiple telescopes showed that the rate of expansion of the universe is different depending on where you look. The nearby universe (measured by the Hubble Space Telescope and Gaia space telescope) has a rate of expansion of 45.6 miles per second (73.5 kilometers per second) per megaparsec, while the more distant background universe (measured by the Planck telescope) is a bit slower, expanding at 41.6 miles per second (67 km per second) per megaparsec.

You do realize this is evidence that the expansion of the universe is accelerating.  When you look at the rate of expansion long ago, you find that it is slower that the rate of expansion in the more recent past.  In other words the rate of expansion is increasing with time.

You then write:

3 hours ago, motlan said:

I believe the universe is expanding at constant velocity.

Then why did you quote an article that refutes that?