B Sun powered by quantum tunneling - question

[brajesh]

I recently found out that for nuclear fusion to occur the temperature needs to be around 100 Million Kelvin and that the hottest part of the sun is only at 27 Million Kelvin. And that the reason nuclear fusion is occurring in the sun is because of quantum tunneling—allowing a very small fraction of the hydrogen to fuse to helium even below the 100MK requirement.

Is this correct?
If so, I have a question.

Q - Is this what prevents the sun from blowing up? In other words, if it was at 100MK then all the hydrogen would fuse to helium and the sun would be used up almost all at once right?

 

[Vanadium 50]

if it was at 100MK then all the hydrogen would fuse to helium and the sun would be used up almost all at once right?

Certainly a lot faster, yes.

 

[PeterDonis]

I recently found out

Where? Please give a specific reference.

I recently found out that for nuclear fusion to occur the temperature needs to be around 100 Million Kelvin

First, there is not a hard cutoff between "occurs" and "doesn't occur", even without taking quantum effects into account. The temperature is only the average kinetic energy of the particles; the relevant quantity is not whether a particular reaction will occur (such as fusion), but how the rate at which it occurs depends on the temperature, which basically amounts to what fraction of the gas particles at a given temperature will be expected to have energies at or above the threshold energy for the reaction.

Second, the threshold energy, and therefore the rate as a function of temperature, depends on the particular fusion reaction; some reactions have lower thresholds than others. See, for example, the graph towards the end of the "Requirements" section in the Wikipedia article on nuclear fusion.

https://en.wikipedia.org/wiki/Nuclear_fusion#Requirements

the reason nuclear fusion is occurring in the sun is because of quantum tunneling

"Quantum tunneling" might be too narrow a term. But it is true that reaction rates calculated with quantum effects taken into account are significantly different than reaction rates calculated without them, and that the former are more accurate.

 

[brajesh]

@PeterDonis nice chart, thank you for the explanation.
I googled "what temperature is needed for fusion" and out popped the result "100M Celcius"

 

[KingGambit]

Where? Please give a specific reference.

I think this is after the OP question.
Because I just watch this video and looking explanation in PF Forum.

 

[brajesh]

 

[PeterDonis]

View attachment 281748

Google is many things, but a single authoritative source for scientific facts is not one of them. I have already explained in a previous post what is wrong with the claim shown in the quote above. The Wikipedia article I linked to earlier is a better starting point; also it gives good references to better sources.