How and how much does is the cosmological red shift affected?

In summary, when observing distant sources in deep space, we see a red shift in the light due to their receding motion from us. This red shift is further distorted by the gravitational potential of our local galaxy, resulting in a more blue shift or no change, depending on the direction of our motion. The impact of this effect varies depending on the velocity of the source and our own velocity relative to our galaxy. Gravitational effects are quadratic in velocity and can be significant when observing matter close to a black hole.
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LuckyNate
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When we look out into deep space we see a red shift in the light from distant sources because they are more or less all receding from us. How is the red shift distorted by passing through our local galactic gravitational well, before hitting us down here on the ground?(more red/more blue/no change) How acute is the impact of this effect?

Please say it so it's easy for me to read, I'm not a mathematician.
 
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More blue for the gravitational potential, and depending on the direction for our motion through the galaxy.
The same effect size is present at the source, if it is within a galaxy.

To estimate the effect sizes:
The motion relative to the galaxy leads to a linear frequency shift. Typical velocities are 200km/s, so the relative shift is ##\frac{200 km/s}{300,000km/s} = \frac{1}{1500}##. We know our own velocity relative to our galaxy, this can be taken into account. The motion of the source depends on the type of source.

Gravitational effects are quadratic in the velocity. Typical escape velocities are 300km/s, so the relative shift is ##\frac{(300 km/s)^2}{(300,000km/s)^2} = \frac{1}{1,000,000}##. This corresponds to a really tiny velocity difference (<1km/s).

This gets different if you observe matter very close to a black hole. There, gravitational redshift (together with the motion of the objects) is important.
 
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To go along with mfb's reply this thread has an article covering the various forms of redshifts and causes.

Its written in a easy to understand manner just scroll down to the Redshift and expansion article

https://www.physicsforums.com/showthread.php?t=705427
 
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FAQ: How and how much does is the cosmological red shift affected?

1. How is cosmological red shift affected by the expansion of the universe?

The cosmological red shift is a result of the expansion of the universe. As the universe expands, the wavelength of light from distant objects is stretched, causing the light to appear more red. This red shift is directly proportional to the distance of the object from us, meaning the farther away an object is, the greater its red shift will be.

2. How does the speed of an object affect cosmological red shift?

The speed of an object does not directly affect cosmological red shift. However, the red shift of an object can give us information about its velocity. For example, an object with a higher red shift is moving away from us at a faster speed compared to an object with a lower red shift.

3. Does the age of the universe play a role in cosmological red shift?

Yes, the age of the universe does play a role in cosmological red shift. As the universe has been expanding for billions of years, light from distant objects has had more time to travel and therefore experience more red shift. This means that objects farther away from us appear more red, indicating a greater distance and longer travel time.

4. How does the density of matter in the universe affect cosmological red shift?

The density of matter in the universe does not directly affect cosmological red shift. However, the amount of matter in the universe does affect the rate of expansion, which in turn affects the amount of red shift observed. A higher density of matter would result in a slower expansion of the universe and therefore less red shift.

5. Can cosmological red shift be used to measure distances in the universe?

Yes, cosmological red shift can be used to measure distances in the universe. By measuring the amount of red shift in the light from a distant object, scientists can determine the object's distance from us. This is known as the cosmological red shift law and is a key tool used in studying the large-scale structure of the universe.

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