Sun

[CedrikG]

Hey everyone

I woud like to know what you think about this. Sun really fascinate me, I see it like a giant camp fire ( which I know it has nothing to do with camp fire, its the fuzion of hydrogen gaz, not wood ). But still, thats the way I see it a little.

I have been teaching primitive survival skill in the forest for years and so, I made many many thousand of fire. A fire can be stable, I can put a certain amount of wood and know that I will be fine for X time, but sometimes, theres something that fail in my fire, making it collapse, or considerably reducing its production time.

We say that sun still has 5 billion years of life approximately. But ... in this ENORMOUS fire, would it be possible that something fail, something collapse, capable to destroy the sun tomorrow ... or is this big fire EXTREMELY stable, impossible for anything to change its helium production. From my experience ... fire is unstable.

Share what you think!

[michael.h.f.wilkinson]

As you say, it is not a fire. What we have is a HUGE ball of plasma, and nothing in the neighbourhood that could fall in (like a comet) would make the slightest impression on it. The ball is stable under its own gravity (quite unlike the fire), and needs no external feed of oxygen or fuel, like a fire does. Fire can collapse on its own because some structure supporting the pile breaks (because it is consumed by the fire). In a ball of plasma, no such collapse can take place, because there are no larger solid structures than atomic particles present.

[David Smith]

In your fire there will be many unknown variables that determine how hot it gets and how long it will burn for e.g. quality of the fuel (including contaminants such as moisture), surrounding environment, airflow, etc. None of these will apply to the Sun so you would think it a little easier to calculate the Sun's life span. However, we still do not fully understand the workings of our star which could throw up something unexpected and cause us to re-think our expectations.

[CedrikG]

Extremely interesting. Thanks a lot!

There is not one single example of sun failure seen from Hubble ?
Also, these X-Flare eruption and highly twisted magnetic field could not disturb anything?

[jabeoo1]

Extremely interesting. Thanks a lot!

There is not one single example of sun failure seen from Hubble ?

Also, these X-Flare eruption and highly twisted magnetic field could not disturb anything?

I don't think we need to worry, these highly twisted magnetic fields that can lead to mass ejections are hardly a significant mass loss to something as massive as the sun.  A main sequence star won't just go bang, its far too happily stable.  Remember our sun is 99% (+ some more even ?) of the total mass of our solar system, there is hardy enough of anything within a light year in any direction from the suns surface to have a pop at it, let alone significantly add or knock mass off it.  The material deep down inside the sun is so dense that a photon generated inside the core takes 10,000-70,000 years to get from the core to our planet.  If it can make a photon struggle its way to the surface you can imagine how difficult it is to upset it by chucking stuff at it.  Just look at what puny Jupiter made of that rubbish comet !      

Sudden changes can occur in binary systems where significant mass exchange takes place between the 2 stellar bodies that orbit one another via a Roche Lobe.  This is where balances are tilted, albeit balances that are on the edge anyway.  Think of it as 'that extra shovel of mass that broke the camels back'. These stars were on the brink, one shovel too much and ignition !  Recurrent nova systems also exist, it seems that even when there is a spanner in the works one is not enough as in nearby RS Ophiuchi.

It is more likely to be relevant to think about what a very large CME could do to us if lined up well enough ! 

[CedrikG]

Great input man. Seeing it this way, I understand better the stability. I watched that video about photon taking sometimes 100 000 years to reach the surface. We can see how DENSE is this soup. Forgot about this detail though, thank for reminding me.