Collision between the Milky Way and Andromeda and Redshift

In summary, the conversation discusses the potential influence of the Milky Way's movement towards the Andromeda galaxy on the redshift observed in other galaxies, and whether this could affect the conclusion of an accelerated expansion of the universe. However, it is noted that there are several reasons why this is not the case, including the fact that distant galaxies are receding from us in all directions at high speeds. Additionally, the potential impact of the Milky Way's local velocity on cosmologists' calculations is brought up, but there is evidence against this hypothesis. Overall, it is concluded that the accelerated approach between the Milky Way and Andromeda is already taken into account in explaining the accelerated expansion of the universe.
  • #1
MartinG
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4
Hi ! My question is the following:

If there is a redshift in astronomical observations with other galaxies, as our Milky Way galaxy is approaching with the Andromeda galaxy, they must surely be in an accelerated approach due to the force of gravity between the two galaxies, and as our galaxy Vía Milky already be in a accelerated movement, it can influence the redshift that occurs in the observations with the other galaxies.

In other words, it could happen that the redshift that is observed with the other galaxies and that would lead to the conclusion that the universe is expanding in an accelerated way, cannot be confused with this accelerated movement that our galaxy would already have in his approach to the Andromeda galaxy.

I ask just in case. Perhaps this situation is already contemplated in the conclusion that is drawn from the accelerated expansion of the universe when the redshift is observed in the observations with the other galaxies, but I ask this question to remove this doubt.

I thank you for the answers and send you greetings.
 
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  • #2
I don't understand a thing you wrote. It sounds like a personal theory, though.

One fact you may be unaware of: M31 is blueshifted.
 
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  • #3
I think what you are saying is that the speed of the Milky Way galaxy as it approaches Andromeda could be confusing our measurements of the redshifts of other galaxies. There are several reasons why this is not the case, including these:

(1) We see distant galaxies receding in all directions. There is no way for motion of the Milky Way to cause distant galaxies to appear to be receding from us no matter which direction we look.

(2) Distant galaxies are receding from us at speeds of 50,000 km/sec and greater. The speed with which the Milky Way is approaching Andromeda is only about 100 km/sec.
 
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  • #5
Vanadium 50 said:
I don't understand a thing you wrote.
The question is whether cosmologists have forgotten to include the local velocity of the Milky Way relative to comoving coordinates in their calculations? Is it possible that this subtlely could have been overlooked by generations of cosmologists?

Or, has the OP overlooked the fact that the local velocity of the MIlky Way would lead to anisotropic redshift/blueshift depending on direction, rather than redshift in all directions depending only on distance and not on direction?
 
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  • #6
PeroK said:
The question is
Got it.

While I agree that the hypothesis that generations of cosmologists (and the astronomers before them) are idiots is a difficult one to support, there is also evidence against it. There is evidence that the Earth is moving with respect to the uniform CMBR, it does not point in the direction of M31, and it is 6x larger.
 
  • #7
If it has already been explained to me that this effect of accelerated approach between the Milky Way and Andromeda is taken into account to explain the accelerated expansion that our universe has at this time.

Thanks.
 

1. What is the collision between the Milky Way and Andromeda?

The collision between the Milky Way and Andromeda is a future event that is estimated to occur in about 4.5 billion years. It is a merger between our galaxy, the Milky Way, and the neighboring galaxy, Andromeda. This collision is expected to result in a new, larger galaxy called Milkomeda.

2. How will the collision impact our solar system?

The collision between the Milky Way and Andromeda is not expected to have a major impact on our solar system. Due to the vast distances between stars, it is unlikely that any of the planets in our solar system will collide with another star during the merger. However, the gravitational interactions between the two galaxies may cause some disruption in the orbits of stars and planets.

3. What is redshift and how does it relate to the collision?

Redshift is a phenomenon in which light from an object appears to have a longer wavelength, shifting towards the red end of the spectrum. This is due to the expansion of the universe, which causes objects to move away from each other and the light to stretch. The collision between the Milky Way and Andromeda will cause a redshift in the light from both galaxies as they merge and move away from each other.

4. Will the collision between the Milky Way and Andromeda affect life on Earth?

No, the collision is not expected to have any significant impact on life on Earth. The distance between our solar system and the merging galaxies is so vast that any potential effects, such as increased radiation, would be minimal. Additionally, the collision will not occur for billions of years, giving any potential life on Earth plenty of time to evolve and adapt.

5. How do scientists predict the collision between the Milky Way and Andromeda?

Scientists use various methods, such as computer simulations and observations of the galaxies' movements, to predict the collision between the Milky Way and Andromeda. They also study the gravitational interactions between the two galaxies and their effects on surrounding objects. These methods allow scientists to make accurate predictions about the future merger of the two galaxies.

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