Lord Kelvin was wrong but was he pessimistic? He wasn’t saying we could never know the answer, or visit the sun, or anything like that. Yes, he guessed wrongly, and too low, but it doesn’t seem to be the case that ‘underestimating a quantity’ is pessimism. If nothing else, the quantity might be ‘number of babies killed’.
It was pessimistic in the sense that under his estimate the sun was steadily cooling and so we’d all freeze to death long before the real sun will present us any trouble.
He estimated the sun was no more than 20 million years old, and presumably did not expect it to last for more than a few tens of millions of years more.
Not that I know of. Gravitational collapse is a really lousy, short-term source of energy, which is why he gave such a shorter estimate. Still on the scale of millions of years, I think.
Lord Kelvin was wrong but was he pessimistic? He wasn’t saying we could never know the answer, or visit the sun, or anything like that. Yes, he guessed wrongly, and too low, but it doesn’t seem to be the case that ‘underestimating a quantity’ is pessimism. If nothing else, the quantity might be ‘number of babies killed’.
It was pessimistic in the sense that under his estimate the sun was steadily cooling and so we’d all freeze to death long before the real sun will present us any trouble.
Did he give an estimate of when we’d all freeze to death?
He estimated the sun was no more than 20 million years old, and presumably did not expect it to last for more than a few tens of millions of years more.
Not that I know of. Gravitational collapse is a really lousy, short-term source of energy, which is why he gave such a shorter estimate. Still on the scale of millions of years, I think.