<p>As relativistic effects will cause clocks to run slower, a frame of reference must be chosen when considering the time of the "big bang". There is a natural and convenient choice of reference frame, based on the cosmic microwave background. The cosmic background appears to be extremely red-shifted light, indicating it is receding from us very fast, due to the expansion of the universe. If we choose a frame in which the CMB is receding equally fast in all directions, we have a convenient frame of reference. It is called the <a href="https://en.wikipedia.org/wiki/Comoving_distance" rel="nofollow">Comoving frame</a>. </p>

<p>Now that we have a frame of reference, we can talk about time and distance in a way that all observers that share this frame can agree. In the comoving frame, the "big bang" occurred about 13.8 billion years ago.</p>

<p>To directly answer the question: The time measured is the time in the comoving frame and relativistic time dialations (time-lapse) are considered.</p>

CC BY-SA 3.0
2015-10-19T21:11:48.430Z
2015-10-19T21:11:48.430Z
James K
<p>We say that our universe is 13.7 billion years ago. During the big bang, it doubled at least 90 times in trillionth of a second (as given <a href="http://www.space.com/52-the-expanding-universe-from-the-big-bang-to-today.html" rel="nofollow">here</a>), and other topological statements.</p>

<p>The question is which time are we talking about. Is the time-lapse considered? If yes, how?</p>

CC BY-SA 3.0
2015-10-19T18:47:29.607Z
Which time-lapse are you referring to?
Walter
<big-bang-theory><space-time><time-dilation>
Is the time lapse considered when estimating the age of the universe?
Shashwat
# Is the time lapse considered when estimating the age of the universe?

(Asked by: username_0 on 2015-10-19)

We say that our universe is 13.7 billion years ago. During the big bang, it doubled at least 90 times in trillionth of a second (as given [here](http://www.space.com/52-the-expanding-universe-from-the-big-bang-to-today.html)), and other topological statements.

The question is which time are we talking about. Is the time-lapse considered? If yes, how?

**Tags:** big-bang-theory, space-time, time-dilation
> **Comments:**
> **username_1**: Which time-lapse are you referring to?  

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## 1 answers

### Answer by username_2 on 2015-10-19. Score: 1 | Accepted answer

As relativistic effects will cause clocks to run slower, a frame of reference must be chosen when considering the time of the "big bang". There is a natural and convenient choice of reference frame, based on the cosmic microwave background. The cosmic background appears to be extremely red-shifted light, indicating it is receding from us very fast, due to the expansion of the universe. If we choose a frame in which the CMB is receding equally fast in all directions, we have a convenient frame of reference. It is called the [Comoving frame](https://en.wikipedia.org/wiki/Comoving_distance).

Now that we have a frame of reference, we can talk about time and distance in a way that all observers that share this frame can agree. In the comoving frame, the "big bang" occurred about 13.8 billion years ago.

To directly answer the question: The time measured is the time in the comoving frame and relativistic time dialations (time-lapse) are considered.


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