<p>The rate of shrinkage is decreasing. The reason is that the core of Jupiter is becoming increasingly electron degenerate. Electron degeneracy pressure is almost independent of temperature. Once degeneracy sets in, an object can continue to cool with almost no change in its interior pressure, and hence no radius change. A cosmic example is a white dwarf.</p>
<p>This is not an on/off process, so at no point will you be able to say &quot;Jupiter has now stopped shrinking&quot;, but Jupiter's radius will not reduce by more than about 10-20% from what it is now. The ultimate fate of Jupiter is to become a cold, ball of metallic hydrogen (with impurities).</p>

CC BY-SA 4.0
2020-07-27T19:50:16.217Z
By fall of metallic hydrogen, do you mean at 14 Kelvin on the surface or are you speaking more generally.   Wouldn't it maintain a helium atmosphere for some time past that?
userLTK
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2020-07-27T21:33:11.083Z
Why would it be at 14k a gazillion years in the future? @userLTK
ProfRob
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2020-07-27T22:05:14.573Z
That's the problem with "ultimate fate" questions, it suggests a ridiculously long time.
userLTK
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2020-07-28T05:07:51.247Z
As I understand it, it _will_ stop shrinking, but very gradually / very slowly or something?
Ioannes
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2020-07-27T18:39:31.987Z
2020-07-27T18:39:31.987Z
ProfRob
<p>Jupiter is currently shrinking due to the Kelvin-Helmholtz mechanism. Will this mechanism eventually hold or getting slower? If so, at what size of Jupiter will it stop and why? If not, what will eventually happen to Jupiter?</p>

CC BY-SA 4.0
2020-07-27T15:57:12.637Z
On a related note, Jupiter has a rather large diffuse core. See my answer [here](https://astronomy.stackexchange.com/a/35069/16685) for further info.
PM 2Ring
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2020-07-27T16:23:54.483Z
@PM2Ring Revealing, thank you.
Ioannes
CC BY-SA 4.0
2020-07-27T17:24:39.650Z
Eventually? Heat death, proton decay, entropy...
Ink blot
<jupiter><temperature>
Will Jupiter eventually stop shrinking?
Ioannes
# Will Jupiter eventually stop shrinking?

(Asked by: username_0 on 2020-07-27)

Jupiter is currently shrinking due to the Kelvin-Helmholtz mechanism. Will this mechanism eventually hold or getting slower? If so, at what size of Jupiter will it stop and why? If not, what will eventually happen to Jupiter?

**Tags:** jupiter, temperature
> **Comments:**
> **username_1**: On a related note, Jupiter has a rather large diffuse core. See my answer [here](https://astronomy.stackexchange.com/a/35069/16685) for further info.  
> **username_0**: @PM2Ring Revealing, thank you.  
> **username_2**: Eventually? Heat death, proton decay, entropy...  

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## 1 answers

### Answer by username_3 on 2020-07-27. Score: 4 | Accepted answer

The rate of shrinkage is decreasing. The reason is that the core of Jupiter is becoming increasingly electron degenerate. Electron degeneracy pressure is almost independent of temperature. Once degeneracy sets in, an object can continue to cool with almost no change in its interior pressure, and hence no radius change. A cosmic example is a white dwarf.

This is not an on/off process, so at no point will you be able to say "Jupiter has now stopped shrinking", but Jupiter's radius will not reduce by more than about 10-20% from what it is now. The ultimate fate of Jupiter is to become a cold, ball of metallic hydrogen (with impurities).

> **Comments:**
> **username_4**: By fall of metallic hydrogen, do you mean at 14 Kelvin on the surface or are you speaking more generally.   Wouldn't it maintain a helium atmosphere for some time past that?  
> **username_3**: Why would it be at 14k a gazillion years in the future? @userLTK  
> **username_4**: That's the problem with "ultimate fate" questions, it suggests a ridiculously long time.  
> **username_0**: As I understand it, it _will_ stop shrinking, but very gradually / very slowly or something?  

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