<p>They would if we could see them far enough away, but cepheid variables are only visible up to about 20 million light years distant. That may sound like a long way, but in astronomical terms it is nearby.</p>

CC BY-SA 4.0
2019-08-04T16:37:55.763Z
20 Mlyr is still enough to see a time dilation of 0.5%.
pela
CC BY-SA 4.0
2019-08-04T07:24:55.980Z
2019-08-04T07:24:55.980Z
Michael Walsby
<p>If a star that has regular pulses(standard candle) is flying away from us at relativistic velocity(very distant), would that pulses look like very sluggish compared to a non-relativistic velocity(close to earth)...something like a clock ticking in a relativistic spaceship and....... ofcourse red-shifted.Thanks.</p>

CC BY-SA 4.0
2019-08-03T21:35:25.353Z
I am not very sure, what you ask. Could you please elaborate?
peterh
CC BY-SA 4.0
2019-08-04T06:56:21.003Z
Wikipedia has a detailed page on [red shift](https://en.wikipedia.org/wiki/Redshift) and it's causes.  Light already has a "built in" pulse - it has a wavelength.
StephenG - Help Ukraine
CC BY-SA 4.0
2019-08-04T12:32:01.677Z
Is this the same for a super nova in the sense that its explosion will last more fore an observer with a relativistic difference in velocities regards the star.Hubble law says more distant a nova is the more its speed.So more speed away from us more slower the picture of its explosion because of Lorentz law..(?)
Janko Bradvica
CC BY-SA 4.0
2019-08-04T17:46:06.733Z
@JankoBradvica -- Yes. In fact, time dilation of Type Ia supernova light curves (and even the temporal evolution of their spectra) has been observed numerous times.
Peter Erwin
CC BY-SA 4.0
2019-08-04T20:08:18.130Z
It's not a Lorentz time dilation, though. It's general relativistic, but the result is the same $(1+z)$ factor as _if_ it were special relativity.
pela
<special-relativity><cepheids>
Lorentz transformation for stars
Janko Bradvica
# Lorentz transformation for stars

(Asked by: username_0 on 2019-08-03)

If a star that has regular pulses(standard candle) is flying away from us at relativistic velocity(very distant), would that pulses look like very sluggish compared to a non-relativistic velocity(close to earth)...something like a clock ticking in a relativistic spaceship and....... ofcourse red-shifted.Thanks.

**Tags:** special-relativity, cepheids

> **Comments:**
> **username_1**: I am not very sure, what you ask. Could you please elaborate?  
> **username_2**: Wikipedia has a detailed page on [red shift](https://en.wikipedia.org/wiki/Redshift) and it's causes.  Light already has a "built in" pulse - it has a wavelength.  
> **username_0**: Is this the same for a super nova in the sense that its explosion will last more fore an observer with a relativistic difference in velocities regards the star.Hubble law says more distant a nova is the more its speed.So more speed away from us more slower the picture of its explosion because of Lorentz law..(?)  
> **username_3**: @JankoBradvica -- Yes. In fact, time dilation of Type Ia supernova light curves (and even the temporal evolution of their spectra) has been observed numerous times.  
> **username_4**: It's not a Lorentz time dilation, though. It's general relativistic, but the result is the same $(1+z)$ factor as _if_ it were special relativity.  

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## 1 answers

### Answer by username_5 on 2019-08-04. Score: 0 | Accepted answer

They would if we could see them far enough away, but cepheid variables are only visible up to about 20 million light years distant. That may sound like a long way, but in astronomical terms it is nearby.

> **Comments:**
> **username_4**: 20 Mlyr is still enough to see a time dilation of 0.5%.  

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