Letter: Earth's odds

From Ralph Estling

You’re going to have to stop frightening the hell out of me. Robert Matthews
claims that there’s a 1 in 100 000 chance that Earth will be ejected from its
orbit, a higher possibility than my winning the Michigan state lottery
(This Week, 12 June, p 17).
I was terrified until I thought about it more carefully.

You don’t say how long a time period is covered by these odds, so I assume
you mean about 5 billion years, after which the Sun becomes a red giant and all
bets are off. I don’t know how often they have a draw on the Michigan lottery,
so let’s say it’s once a month.

That means I’ll have 60 billion chances to win it before the Sun toasts
Michigan to a cinder. Again, I don’t know what the odds are for winning it once,
but if I have 60 billion goes at it I think my odds won’t be all that
bad—and they should be considerably better than the odds of a passing star
using Jupiter to knock Earth for six.

Except that I don’t ever buy tickets for the Michigan state lottery. And even
if I did, I doubt I could keep it up every month for the next 5 billion
years.

Unless we compare like with like, my horse will always be faster than your
pig is fat.

Ilminster, Somerset