Quote:
Originally Posted by PAPPACLART
Becuase the sun produces almost as much fuel as it burns. No gas is stored it just keeps burning and producing almost infinately  |
oh dear god, i can't let this one go unnoticed...
the sun does not produce fuel, it consumes it, it burns hydrogen at a rate of ~5 million tons every second, converting hydrogen into helium by fusion
the reason the sun doesn't explode out into space is because the outward force of the massive nuclear fusion reaction is about equal to the force of gravity trying to squeeze all those trillions of trillions of tons of gas back together.
as the sun converts hydrogen into helium, the helium will form a core, adding more helium to it as the sun uses up all the hydrogen until eventually the pressure due to gravity is enough to start helium fusion, converting the helium to heavier elements. the increased rate of fusion will cause the sun to swell until it is about the size of earth's orbit
when helium fusion runs out of fuel there will be nothing to support the sun and the gasses that formed the outer parts will drift to form a planetary nebula or similar. the now inert core will be left, barren and cold, having vaporised the first four planets, leaving the solar system alone in the cold dark vacuum of space
so, to answer the original question:
Quote:
Originally Posted by SoulKiss
Q: "Why does the sun go on shining?"
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the apparently infinite life of the sun is an illusion, due to the timescales of solar evolution...