T20 errata?

[Nearside]

Howdy, all.

Just reading through the T20 book (skimming, really) and I think I've found a small mistake.

On page 372 (wow!) under Step 4 - Star Spectral Classification, it reads, for F,G,K...
"... they generally have lifespans numbering millions if not tens of millions of years."

Should those millions read billions?

 

[chron187]

Actiually the Sun is supposed to last for 6 billion more years before either going nova or going red though that wont be much of a problem because in 1 billion years our carbon dioxide will have all become one with the ground and all life on this planet will die

 

[Tanuki]

Originally posted by Chron:
Actiually the Sun is supposed to last for 6 billion more years before either going nova or going red though that wont be much of a problem because in 1 billion years our carbon dioxide will have all become one with the ground and all life on this planet will die

Sol will not go nova. It's too small for a supernova and novas happen on white dwarfs (long dead stars) in binary systems where they gradually build up hydrogen on the surface. Once they reach a critical amount, fusion begins catastrophically. Hydrogen burns to helium or is blasted away and everything settles back down until enough hydrogen builds up for another nova.

Carbon is continually cycled back into the environment by volcanoes and by weathering of carbon rich rocks. We are not going to run out of carbon.

 

[EvilDrGanymede]

Originally posted by Chron:
Actiually the Sun is supposed to last for 6 billion more years before either going nova or going red though that wont be much of a problem because in 1 billion years our carbon dioxide will have all become one with the ground and all life on this planet will die

ISTR the current thinking is that by about 1 billion years from now, the sun will have warmed up by enough to make life rather difficult on Earth (since main sequence stars get warmer as they get older). IIRC the increased heat would drive the CO2 *out* of the rocks and into the atmosphere and you'd get a runaway greenhouse effect. Or something like that.

As for the star ages, billions - tens of billions sounds right. Though Type A stars may have a main sequence lifespan of only a few hundred million years.

 

[Simon Jester]

Originally posted by Evil Dr Ganymede:
ISTR the current thinking is that by about 1 billion years from now, the sun will have warmed up by enough to make life rather difficult on Earth (since main sequence stars get warmer as they get older). IIRC the increased heat would drive the CO2 *out* of the rocks and into the atmosphere and you'd get a runaway greenhouse effect. Or something like that.

Since, in 1 billion years, mankind shall have either gotten far off this rock or killed itself off, it doesn't really matter one ay or another. Leave it to the rats and cockroaches to figure out which will happen.

Simon Jester