[Nataku X]

Magnetic argument, I believe, is that the Earth's magnetic field is decaying at a rapid rate such that it can't be more than a few K years.

[FactQuest]

Magnetic argument, I believe, is that the Earth's magnetic field is decaying at a rapid rate such that it can't be more than a few K years.

Oh, ok, thanks. Of course, that's based on the assumption the rate of decay is constant. Which is probably unproven. I wonder which way the preponderance of evidence leans.