It seems that Mother Earth is like most women: often moody, mostly incomprehensible and she doesn’t like to admit her age.
Well, okay, I don’t know about most women, but it certainly applies to Momma Earth.
In fact she hates it so much, she endlessly undergoes surgery to remove any possible hints of age, what with her shifting, reforming and changing crust all the time.
The oldest rock we were lucky enough to find, a tough little zircon crystal picked up in Australia, was measured at 4.4 billion years according to its uranium decay.
So if she doesn’t want to give out her age, what do nosy scientists do?
After all, Luna is literally a chip of the old block, having broken away in a collision with the hypothetical planet Theia – an event aptly known as the Big Whack.
Moon samples brought back by the Apollo missions say earth may be 4 billion years old, as close as we can peg it.
But geologists swear not by the moon, the inconstant moon.
Other sources are also questioned of course, such as the highly independent meteorites. Nothing is left out.
The 12-zero-figures determined of all three sample elements correlate somewhat, putting Momma Earth’s age at somewhere between 4 and 5 billion.
More or less.
But that is just the technicality we are trying to dig up: the difference between 4 billion and 5 billion for example is, well, 1 billion.
As Ted Turner put it, that’s “a nice round number.”
Isn’t that a bit much to be vague about?
Well, compared to the age of the rest of the universe, it’s a fairly small error margin. We’re still learning, and Momma Earth is no easy lady to deal with.
Still, with these margins, don’t ever lend a geologist money — they consider a million years to be recent.