The Sun's Fire: Low O2 and Carbon Emissions

[gokhul]

There is only 0.77% of oxygen in sun
And only 0.29% of carbon
The question is
there is only small amount of o2 but how how sun is surrounded by fire with very less emissions of carbon
( referred to Wikipedia for amount of gas in sun)

 

[jfizzix]

The sun is surrounded by fire in that it is surrounded by gas that's hot enough to be glowing red (which is as good a definition for fire as any). Some of it's even hot enough to be plasma, but that's not the point to be made here.

Even though there's probably no significant amounts of chemical combustion going on, the nuclear fusion at the core certainly keeps the rest of the Sun hot enough to be the glowing ball of "fire" we see.

 

[davenn]

The question is
there is only small amount of o2 but how how sun is surrounded by fire with very less emissions of carbon
( referred to Wikipedia for amount of gas in sun)

its not fire in the sense of what is usually termed fire as the fire in a furnace or your home fireplace
nothing is burning, there are NO flames. As you noted, O₂ is almost non-existent

The heat from the sun is primarily caused by the nuclear reactions occurring in its core.
An interesting feature is the Suns corona which varies from 1 to 3 million Kelvin, very much hotter than the photosphere surface
that is around 5800 K
The jury is still out on all the causes for this, but the sun's magnetic fields do play a part.

The sun is surrounded by fire in that it is surrounded by gas that's hot enough to be glowing red (which is as good a definition for fire as any).

that is incorrect and quite misleading

Even though there's probably no significant amounts of chemical combustion going on

there is no combustion going on
regards
Dave

 

[gokhul]

its not fire in the sense of what is usually termed fire as the fire in a furnace or your home fireplace
nothing is burning, there are NO flames. As you noted, O₂ is almost non-existent

The heat from the sun is primarily caused by the nuclear reactions occurring in its core.
An interesting feature is the Suns corona which varies from 1 to 3 million Kelvin, very much hotter than the photosphere surface
that is around 5800 K
The jury is still out on all the causes for this, but the sun's magnetic fields do play a part.

that is incorrect and quite misleading
there is no combustion going on
regards
Dave

Then how when objects get near catch up flame

 

[gokhul]

its not fire in the sense of what is usually termed fire as the fire in a furnace or your home fireplace
nothing is burning, there are NO flames. As you noted, O₂ is almost non-existent

The heat from the sun is primarily caused by the nuclear reactions occurring in its core.
An interesting feature is the Suns corona which varies from 1 to 3 million Kelvin, very much hotter than the photosphere surface
that is around 5800 K
The jury is still out on all the causes for this, but the sun's magnetic fields do play a part.

that is incorrect and quite misleading
there is no combustion going on
regards
Dave

And what type of nuclear reaction takes place fission or fussion

 

[Drakkith]

Then how when objects get near catch up flame

Get near what? The Sun?

And what type of nuclear reaction takes place fission or fussion

Fusion reactions occur in the Sun's core.

https://en.wikipedia.org/wiki/Sun#Core

 

[davenn]

Then how when objects get near catch up flame

what objects ?

 

[gokhul]

what objects ?

space ships or comets

 

[jfizzix]

Okay, I'm here to learn as much as anyone else (mea culpa).

Are you saying that fire is not red-hot gas,
or that the Sun is not surrounded by gas?

Not counting the corona (which doesn't produce most of the light we see anyway)
the surface of the Sun's a mix of hot gas, and gas hot enough to become a plasma
If you work out the Boltzmann statistics for hydrogen gas, at around 5800K, you'll find that most of the surface of the sun's in the gas phase, and not in the plasma phase.

 

[DrClaude]

Okay, I'm here to learn as much as anyone else (mea culpa).

Are you saying that fire is not red-hot gas,
or that the Sun is not surrounded by gas?

I don't know if this is what @davenn had in mind, but I would also not call it fire, as there is no combustion taking place.

 

[davenn]

space ships or comets

spaceships ? ... well don't think any made on Earth have ever got close enough to the sun to worry about
I can't find any specific info links, maybe others more informed than me can confirm my thoughts @DrClaude , @mfb

spacecraft will be mainly metal and maybe some tanks of fuel and other than those fuel tanks exploding when the contents reaches ignition temperature
all the remaining metallic parts would simply melt and vaporise

The similar thing I suspect would happen to comets and meteoroids
Comets are mainly lumps of rock dust and ice. The ices are going to vent from the comet, melt and vaporise
Trapped pockets of ice and gasses could well cause lots of rock fracturing to occur, breaking sections of the comet apart
but in the end, the rock or ice is going to melt and vaporise once the required temperatures are reached

Regards
Dave

 

[rootone]

Then how when objects get near catch up flame

They don't, what has given you this idea?
No comet or other object approaching the Sun will catch fire because there is no oxygen in space.
They can get very hot though due to direct solar radiation, and comets have been seen to disintegrate.
These basically melted and fell apart, they didn't catch fire in the normal use of the word 'fire' (=combustion).

Also there are no flames around the sun, what you are seeing is electromagnetic radiation (light) which is generated by the fusion reactions in the Sun's core. (You can also directly feel infrared radiation from the Sun as heat on a clear hot day.)

 

[mfb]

If you work out the Boltzmann statistics for hydrogen gas, at around 5800K, you'll find that most of the surface of the sun's in the gas phase, and not in the plasma phase.

It is called plasma even if most atoms are neutral, as long as the ionized atoms and electrons dominate the behavior of the matter (and they certainly do that in the sun).

Then how when objects get near catch up flame

They do not. They can melt and evaporate, depending on their chemical composition some chemical reactions might take place, but unless you carry around oxygen in the spacecraft (or comet) no combustion with oxygen happens.

 

[davenn]

They do not. They can melt and evaporate, depending on their chemical composition some chemical reactions might take place, but unless you carry around oxygen in the spacecraft (or comet) no combustion with oxygen happens.

cool, so I covered it pretty well


Dave

 

[jfizzix]

I stand corrected