<p>As many calculations have been done on whether metallic hydrogen is metastable or not in low-pressure environment, It occurred to me that by the fact that we have not observed any metallic hydrogen so far in space, shouldn't this be a strong case for supporting the notion that metallic hydrogen is not stable without pressure?</p>
<p>It seems likely to me that metallic hydrogen could be pulled from the core of a gas giant, as in the case of Hot Jupiters, which are so close to their star, that they eventually are ripped apart by tidal forces; in this events their insides would be &quot;gutted&quot; out, including metallic hydrogen, which could be observed, were such an event to happen.</p>

CC BY-SA 4.0
2021-11-10T11:44:40.907Z
I guess you would have to re-read your references what 'low-pressure' really means in the specific context. I don't know of a single claim that metallic hydrogen exist at pressures in upper atmospheres / open space.
AtmosphericPrisonEscape
CC BY-SA 4.0
2021-11-10T16:00:18.157Z
"There is a physically reasonable hypothesis about the
metastability of small pieces of the metallic hydrogen
during a very long time interval (∼Gyrs), initiated by the
theoretical works on the possibility of the zero-pressure
metastable state" - https://arxiv.org/pdf/1202.5920.pdf
ksousa
CC BY-SA 4.0
2021-11-10T21:34:27.387Z
@ksousa Indeed! In Physics SE: [Are there published predictions that hydrogen could remain metallic at ambient pressure?](https://physics.stackexchange.com/q/308290/83380) and also [For the recently reported production (January 2017) of metallic hydrogen in the laboratory - what is the evidence exactly?](https://physics.stackexchange.com/q/308155/83380) and in Space SE [Better understanding of the "Rivers of metallic hydrogen" in the atmosphere of Jupiter?](https://space.stackexchange.com/q/21649/12102)
uhoh
CC BY-SA 4.0
2021-11-10T21:34:52.163Z
and [Helium rain inside metallic hydrogen within Jupiter, conditions and experiments?](https://astronomy.stackexchange.com/q/25478/7982) and more tangentially [Has (theoretically) metastable metallic hydrogen been considered for use as a propellant?](https://space.stackexchange.com/q/19947/12102) and [Would (theoretically) metastable solid metallic hydrogen even need an oxidizer?](https://space.stackexchange.com/q/19950/12102)
uhoh
CC BY-SA 4.0
2021-11-11T00:21:29.317Z
@ksousa as you have described, there are models that put metallic hydrogen's metastability at the Gyrs/Billion year time period. My point is, the absolute lack of observational evidence for metallic hydrogen should weaken the very long-lived models, as if it were to last so long, we would have detected them by now. If we can detect radionuclides from Przybylski's star and others with very short lived half-life's, then it seem's doable were M.hydrogen to be stable for so long.
C-Consciousness
<observational-astronomy><spectroscopy><gas-giants><hot-jupiter>
Could we optically observe metallic hydrogen in space?
C-Consciousness
# Could we optically observe metallic hydrogen in space?

(Asked by: username_0 on 2021-11-10)

As many calculations have been done on whether metallic hydrogen is metastable or not in low-pressure environment, It occurred to me that by the fact that we have not observed any metallic hydrogen so far in space, shouldn't this be a strong case for supporting the notion that metallic hydrogen is not stable without pressure?

It seems likely to me that metallic hydrogen could be pulled from the core of a gas giant, as in the case of Hot Jupiters, which are so close to their star, that they eventually are ripped apart by tidal forces; in this events their insides would be "gutted" out, including metallic hydrogen, which could be observed, were such an event to happen.

**Tags:** observational-astronomy, spectroscopy, gas-giants, hot-jupiter

> **Comments:**
> **username_1**: I guess you would have to re-read your references what 'low-pressure' really means in the specific context. I don't know of a single claim that metallic hydrogen exist at pressures in upper atmospheres / open space.  
> **username_2**: "There is a physically reasonable hypothesis about the metastability of small pieces of the metallic hydrogen during a very long time interval (∼Gyrs), initiated by the theoretical works on the possibility of the zero-pressure metastable state" - https://arxiv.org/pdf/1202.5920.pdf  
> **username_3**: @username_2 Indeed! In Physics SE: [Are there published predictions that hydrogen could remain metallic at ambient pressure?](https://physics.stackexchange.com/q/308290/83380) and also [For the recently reported production (January 2017) of metallic hydrogen in the laboratory - what is the evidence exactly?](https://physics.stackexchange.com/q/308155/83380) and in Space SE [Better understanding of the "Rivers of metallic hydrogen" in the atmosphere of Jupiter?](https://space.stackexchange.com/q/21649/12102)  
> **username_3**: and [Helium rain inside metallic hydrogen within Jupiter, conditions and experiments?](https://astronomy.stackexchange.com/q/25478/7982) and more tangentially [Has (theoretically) metastable metallic hydrogen been considered for use as a propellant?](https://space.stackexchange.com/q/19947/12102) and [Would (theoretically) metastable solid metallic hydrogen even need an oxidizer?](https://space.stackexchange.com/q/19950/12102)  
> **username_0**: @username_2 as you have described, there are models that put metallic hydrogen's metastability at the Gyrs/Billion year time period. My point is, the absolute lack of observational evidence for metallic hydrogen should weaken the very long-lived models, as if it were to last so long, we would have detected them by now. If we can detect radionuclides from Przybylski's star and others with very short lived half-life's, then it seem's doable were M.hydrogen to be stable for so long.  

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## 0 answers

