Dr. Eric Haseltine

So you can see how far away something is by the amount of redshift, assuming you have a standard star with a standard emission spectrum, which is an assumption, which may not be true because the things that are farther away, maybe they had different chemistry or something at that time.

Then there's somebody who said, well, no, maybe light gets tired after traveling for X billion years.

Maybe it loses some energy.

Well, that's been, quote, disproven.

But then some people say, well, maybe it hasn't been disproven.

But you have the Hubble tension.

You have different measurements of the expansion of the universe, which are completely incompatible, but both true, which tells you, hmm, some basic things we understood about the universe cannot be true.

Dark energy, dark matter.

And so I think that we know because of things like dark energy and dark matter and Hawking radiation and things like that, we know we're very limited really in what we know.

And so because we know that we don't know, I think that's where these things are.

I think they are most likely some really shocking fundamental physics that we just can't get our heads around right now.

You know what it's not.

We don't know what it is.

And it may not be true.

I mean, there are some theories that say that it's just gravity isn't constant across the whole universe in time.

Like maybe the laws of physics actually change over time.

Well, yeah, maybe.

Who says that Planck's constant has to stay the same throughout all time?

Totally.

Do we understand why it is what it is?