Terence Tao

But they can get closer over time.

The process of getting closer often means that you have to discard your initial intuitions.

Astronomy provides great examples.

An initial model of the world is flat because it looks flat, and it's big.

The rest of the universe, the sun, for example, looks really tiny.

And so you start off with a model, which is actually really far from reality, but it fits kind of the observations that you have.

So things look good, but over time, as you make more and more observations, bring it closer to reality, the model gets dragged along with it.

And so over time, we had to realize that the Earth was round,

that it spins, it goes around the solar system, the solar system goes around the galaxy, and so on and so forth.

And the universe is expanding.

Expansion is self-expanding, accelerating.

And in fact, very recently in this year or so, even the acceleration of the universe itself is evidence that it's non-constant.

And the explanation behind why that is... It's catching up.

It's catching up.

I mean, it's still, you know, the dark matter, dark energy, this kind of thing.

Yes.

We have a model that sort of explains, that fits the data really well.

It just has a few parameters that you have to specify.

But so, you know, people say, oh, that's fudge factors.

You know, with enough fudge factors, you can explain anything.