The sun is still thought to be about halfway through it's 10 billion year
life cycle. What's changed (or at least better understood) is that its
temperature is gradually increasing throughout the time it spends on the
main sequence. Well before it evolves into a red giant, this more gradual
warming is expected to trigger a runaway greenhouse effect on the earth,
turning it into another Venus. So instead of having 5 billion years left,
we may have 1 billion. (I suspect your friend remembered that part wrong
and thought they said million.)


"Carusus" wrote in message
...
A friend who is normally reliable, tells me he read an article in
Scientific
American recently about the temperature of the sun's corona in which it
was
stated that the sun's life expectancy was far shorter than we first
thought - about one million years (I suspect he may have got that bit
wrong)
Anyone know this article?
Thanks