<p>Because gravity holds the sun together.</p>
<p>The core of the sun is in a stable balance between gravity pulling it together, and the pressure generated by the heat which pushes out.  The balance is maintained.  If gravity were to start to &quot;win&quot; and cause the core to contract, the core would be compressed, which would increase the rate of fusion, heating the core and the pressure, which would cause the core to expand.  If you work out the maths, it turns out that this is nicely stable: you don't get pulsations of heating and cooling.</p>

CC BY-SA 4.0
2021-11-30T05:48:01.677Z
2021-11-30T05:48:01.677Z
James K
<p>Because of fusion inside the sun, it pushes it apart, why sun doesn't explode then? The pressure inside should make it explode right?</p>

CC BY-SA 4.0
2021-11-30T09:56:53.040Z
Why don't people explode? From https://en.wikipedia.org/wiki/Solar_core At the center of the Sun, fusion power is estimated by models to be about 276.5 watts/m³. Despite its intense temperature, the peak power generating density of the core overall is similar to an active compost heap, and is lower than the power density produced by the metabolism of an adult human. The Sun is much hotter than a compost heap due to the Sun's enormous volume and limited thermal conductivity.
PM 2Ring
CC BY-SA 4.0
2021-11-30T17:00:47.770Z
The pressure inside is produced by the gravity compessing the matter of the sun.  The heat and temperature at the core fuse hydrogen and produce energy, and that energy heats of the matter of the sun and causes it to try to expand.  Thus there is a balance between expansion and contraction in the Sun.
M. A. Golding
<the-sun>
Can the sun explode in fact?
Rutwik Kumar
# Can the sun explode in fact?

(Asked by: username_0 on 2021-11-30)

Because of fusion inside the sun, it pushes it apart, why sun doesn't explode then? The pressure inside should make it explode right?

**Tags:** the-sun

> **Comments:**
> **username_1**: Why don't people explode? From https://en.wikipedia.org/wiki/Solar_core At the center of the Sun, fusion power is estimated by models to be about 276.5 watts/m³. Despite its intense temperature, the peak power generating density of the core overall is similar to an active compost heap, and is lower than the power density produced by the metabolism of an adult human. The Sun is much hotter than a compost heap due to the Sun's enormous volume and limited thermal conductivity.  
> **username_2**: The pressure inside is produced by the gravity compessing the matter of the sun.  The heat and temperature at the core fuse hydrogen and produce energy, and that energy heats of the matter of the sun and causes it to try to expand.  Thus there is a balance between expansion and contraction in the Sun.  

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## 1 answers

### Answer by username_3 on 2021-11-30. Score: 4 | Accepted answer

Because gravity holds the sun together.

The core of the sun is in a stable balance between gravity pulling it together, and the pressure generated by the heat which pushes out. The balance is maintained. If gravity were to start to "win" and cause the core to contract, the core would be compressed, which would increase the rate of fusion, heating the core and the pressure, which would cause the core to expand. If you work out the maths, it turns out that this is nicely stable: you don't get pulsations of heating and cooling.


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