<p>The rate of star formation in the universe <a href="https://astrobites.org/2016/11/11/the-changing-star-formation-rate-of-the-universe/" rel="nofollow noreferrer">peaked about 3.5 billion years after the Big Bang</a>, or <a href="http://www.space.com/18370-universe-star-formation-rate-decline.html" rel="nofollow noreferrer">2.7 billion years after it</a>, according to a different study—in any case, for most of the universe's lifetime fewer and fewer stars have been forming each year. Though I don't have precise data on the death rate, on the whole <a href="https://www.theguardian.com/science/2015/aug/10/universe-slowly-dying-gama-old-stars-fade-faster-than-new-ones-born" rel="nofollow noreferrer">the number of stars is decreasing</a> as more old stars die than new ones form.</p>

<p>Meanwhile, the light from old stars is being <a href="https://en.wikipedia.org/wiki/Redshift" rel="nofollow noreferrer">redshifted</a> out of existence by the expansion of the universe, which is itself accelerating.</p>

<p>I'm sure there's a mathematical model that can quantify this properly, but I think those two facts, combined, must be the answer to why the sky isn't getting brighter.</p>

CC BY-SA 3.0
2017-05-17T01:04:31.557Z
2017-05-17T01:04:31.557Z
pablodf76
<p>Night sky is dark because light from distant stars has yet not reached our earth. Light emitted by stars formed after the instant of creation i.e. 13.7 billion light years ago is on the way to reach us. As light from these distant stars reach us, night sky must keep getting brighter.<br>
How true is this? And to what extent? Can one day night sky become as bright as a day?</p>

CC BY-SA 3.0
2017-05-15T20:21:26.000Z
Have you looked up "Oblers paradox"?  There are some issues with your question, that may distract from it. Stars were not formed "at the moment of creation". They started forming some 100 million years later, and have continued to form since then.
James K
CC BY-SA 3.0
2017-05-16T06:24:38.410Z
Yes, the issue regarding instant of creation is now edited. Olbers paradox does gives an insight into this.
pooja somani
CC BY-SA 3.0
2017-05-16T20:18:41.220Z
It's a great question!
Fattie
<star><night-sky>
Is night sky getting brighter day by day?
pooja somani
# Is night sky getting brighter day by day?

(Asked by: username_0 on 2017-05-15)

Night sky is dark because light from distant stars has yet not reached our earth. Light emitted by stars formed after the instant of creation i.e. 13.7 billion light years ago is on the way to reach us. As light from these distant stars reach us, night sky must keep getting brighter.  
How true is this? And to what extent? Can one day night sky become as bright as a day?

**Tags:** star, night-sky

> **Comments:**
> **username_1**: Have you looked up "Oblers paradox"?  There are some issues with your question, that may distract from it. Stars were not formed "at the moment of creation". They started forming some 100 million years later, and have continued to form since then.  
> **username_0**: Yes, the issue regarding instant of creation is now edited. Olbers paradox does gives an insight into this.  
> **username_2**: It's a great question!  

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## 1 answers

### Answer by username_3 on 2017-05-17. Score: 4 | Accepted answer

The rate of star formation in the universe [peaked about 3.5 billion years after the Big Bang](https://astrobites.org/2016/11/11/the-changing-star-formation-rate-of-the-universe/), or [2.7 billion years after it](http://www.space.com/18370-universe-star-formation-rate-decline.html), according to a different study—in any case, for most of the universe's lifetime fewer and fewer stars have been forming each year. Though I don't have precise data on the death rate, on the whole [the number of stars is decreasing](https://www.theguardian.com/science/2015/aug/10/universe-slowly-dying-gama-old-stars-fade-faster-than-new-ones-born) as more old stars die than new ones form.

Meanwhile, the light from old stars is being [redshifted](https://en.wikipedia.org/wiki/Redshift) out of existence by the expansion of the universe, which is itself accelerating.

I'm sure there's a mathematical model that can quantify this properly, but I think those two facts, combined, must be the answer to why the sky isn't getting brighter.


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