The Hubble Constant

[ysabetwordsmith]

There are two ways to generate the Hubble constant (the rate at which the universe expands) and they disagree.  One uses data from the early universe, another from the late universe.  Has anyone considered that they might both be right, and the rate was different in the early universe than in the late universe?

In general, if you're not sure what to do, try lots of different things and see which works best.  Get different groups of people coming at it from different angles.  Most importantly, offer the problem to young  mathematicians, physicists, and astronomers who are just entering the field and don't have a dog in the fight yet.  They're more likely to find a solution than the old people who already have a strong stance.

And don't worry too much about it.  You're not going to understand everything about the universe even after you solve this bit.  It's just one more step.  An important step, but not everything.  It's not worth freaking out because you don't have the answer.  You will never have all the answers, and that's what makes it interesting.

Comments

[heron61]

Yep, every time I see a factual disagreement like this I'm thrilled, because it means there's more for us to discover and we aren't far from doing so. I keep hoping we'll get FTL or even just relativistic travel out of one discovery or other, but given humanity at the moment, it's likely for the best if we grow up as a species a bit before we hit the interstellar stage.

Thoughts

[ysabetwordsmith]

>> Yep, every time I see a factual disagreement like this I'm thrilled, because it means there's more for us to discover and we aren't far from doing so.<<

I agree.

>> I keep hoping we'll get FTL or even just relativistic travel out of one discovery or other,<<

That would be great.

>> but given humanity at the moment, it's likely for the best if we grow up as a species a bit before we hit the interstellar stage. <<

Yyyyyeah. But I'm not feeling hopeful about Drake's Equation here.

[siliconshaman]

I believe the current model of the universe is exactly that. It went through an early inflationary period and then settled down to a slower rate, sort of like this

Okay ...

[ysabetwordsmith]

That makes more sense.

[zeeth_kyrah]

Almost like the universe is *vibrating* with large pulses or waves of spacetime. Or like the density of spacetime hit a plateau of some kind while relaxing, and unbound some more energies at that point, which are then able to spread out faster.

If you fill up a rubber balloon, the skin is quite tight at first (the molecules are crowded and bind to each other and many points), but then at an early point if the pressure is enough the structure suddenly becomes much easier to inflate (the molecules aren't binding so tightly in so many places anyore). Maybe this is like that - the system was originally bound tightly due to density and closeness, but eventually stretched enough that relaxing was easier than binding.