# Factor of how much linear size scale has changed

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• bobo1455
In summary, the linear size-scale of the Universe has changed by a factor of 1/(1+z) between the time the light was emitted from the galaxy and now. This factor can be calculated by finding the initial red shift z and using the equation linear size scale = 1 / (1+z). The linear size scale itself represents the factor of change in the size of the Universe.
bobo1455
Question: By what factor has the linear size-scale of the Universe changed between when the light was emitted from the galaxy and now?

The question gives the red shift z and I have the equation linear size scale = 1 / 1 + z and I know how to calculate the linear size scale. But I'm a little confused as to what the question is saying. It is asking about the factor of how much the linear size scale has changed right? So if I just give the linear size scale, the answer won't be fully correct. So I'm assuming to calculate the factor, I would need to find the initial red shift z and calculate the exponent which will give me the new linear size scale that I calculated previously? Thanks for your help.

I don't quite understand what you are asking. By definition, 'now' means z=0 and the scale factor a = 1. So when you calculate the size scale a = 1/(1+z) at the time of emission that tells you the factor by which the size scale has changed from then to now. If you are 6 feet tall today and were 3 feet tall when you were 8 years old, you were 0.5X as tall then as you are now.

Ok I understand. The linear size scale itself is the factor by which the size of the universe changed. I thought the question is more complex than what it really is asking. Thanks.

## 1. What is a linear size scale?

A linear size scale is a measurement of length or distance, typically in one dimension. It is used to describe the size or magnitude of an object or system. Examples of common linear size scales include millimeters, centimeters, meters, and kilometers.

## 2. How is the factor of linear size scale change calculated?

The factor of linear size scale change is calculated by dividing the final size or length of an object or system by its initial size or length. This results in a ratio that represents the change in size or length over time.

## 3. What factors can cause a change in linear size scale?

Changes in linear size scale can be caused by a variety of factors, such as growth or shrinkage due to physical or chemical processes, stretching or compression, or changes in temperature or pressure.

## 4. How does the factor of linear size scale change relate to other scientific concepts?

The factor of linear size scale change is related to concepts such as scaling, proportionality, and dimensional analysis. It is also important in fields such as physics, engineering, and biology, where understanding the relationship between size and function is crucial.

## 5. Can the factor of linear size scale change be negative?

Yes, the factor of linear size scale change can be negative if the final size or length is smaller than the initial size or length. This can occur, for example, when an object is compressed or has undergone a chemical reaction that results in a decrease in size.

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