<p>The simple answer is that atmospheric refraction makes the disk of the sun visible at sunrise or sunset, when it's actually <a href="http://piecubed.co.uk/atmospheric-refraction/" rel="nofollow noreferrer">half a degree or so below the horizon</a>:</p>

<p><img src="https://i.sstatic.net/mhGJu.gif" alt="enter image description here"></p>

<p>In reality, both the extent of refraction of the sun's disk and the refraction of the apparent horizon come into play. Both depend on the atmosphere's density and temperature profile; which changes irregularly. That makes it <a href="http://mintaka.sdsu.edu/GF/explain/sunset_time.html" rel="nofollow noreferrer">impossible to predict exact sunrise or sunset times</a> when there is an atmosphere.</p>

CC BY-SA 3.0
2014-11-26T15:58:44.547Z
2014-11-26T15:58:44.547Z
Wayfaring Stranger
<p>What is the effect of absence of atmospheric refraction on sin rise and sunset time?
Is it will be delayed or earlier for sunrise and sunset, and why?
Thank you:)</p>

<the-sun><atmospheric-effects>
Effect of the absence of atmospheric refraction to sun rise and sunset times
user9686
# Effect of the absence of atmospheric refraction to sun rise and sunset times

(Asked by: username_0 on 2014-11-25)

What is the effect of absence of atmospheric refraction on sin rise and sunset time?
Is it will be delayed or earlier for sunrise and sunset, and why?
Thank you:)

**Tags:** the-sun, atmospheric-effects


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## 1 answers

### Answer by username_1 on 2014-11-26. Score: 1 | Accepted answer

The simple answer is that atmospheric refraction makes the disk of the sun visible at sunrise or sunset, when it's actually [half a degree or so below the horizon](http://piecubed.co.uk/atmospheric-refraction/):

![enter image description here](https://i.sstatic.net/mhGJu.gif)

In reality, both the extent of refraction of the sun's disk and the refraction of the apparent horizon come into play. Both depend on the atmosphere's density and temperature profile; which changes irregularly. That makes it [impossible to predict exact sunrise or sunset times](http://mintaka.sdsu.edu/GF/explain/sunset_time.html) when there is an atmosphere.


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