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this post was submitted on 16 Mar 2024
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It seems odd to me that the universe would be expanding at the same consistent spherical shape. I've seen plenty of explosions and they never look like that. The big bang, which consisted of literally all matter in the universe would surely be no different.
Except it’s not that they are finding the expansion rate is different in some directions. Instead they have two completely different ways of calculating the rate of expansion. One uses the cosmic microwave background radiation left over from the Big Bang. The other uses Cepheid stars.
The problem is that the Cepheid calculation is much higher than the CMB one. Both show the universe is expanding, but both give radically different number for that rate of expansion.
So, it’s not that the expansion’s not spherical. It’s that we fundamentally don’t understand something to be able to nail down what that expansion rate is.
It’s because CMB stopped for coffee, obviously.
(That was a great explanation, btw.)
It just wraps around, like a videogame. Duh...
Just to confirm, the expansion is the same in different directions under both methods of measuring?
Under the CMB method, it sounds like the calculation gives the same expansion rate everywhere. Under the Cepheid method, they get a different expansion rate, but it’s the same in every direction. Apparently, this isn’t the first time it’s been seen. What’s new here is that they did the calculation for 1000 Cepheid variable stars. So, they’ve confirmed an already known discrepancy isn’t down to something weird on the few they’ve looked at in the past.
So, the conflict here is likely down to our understanding of ether the CMB or Cepheid variables.
I wish the article had broken it down the way you did. Thanks!
Ah ok. Thanks for the correction.
The only thing spherical is the visible universe from earth that we can see. Both in time and distance. Due to the expansion of space that volume is increasing.
The entire universe could be infinite and take on any number of infinite shapes. Our local universe could be completely different from the rest of the universe and we'll never be able to know..it's wild.
Recent experiments trying to determine what the curvature of space-time is in the visible universe has concluded that it's pretty much flat But it's entirely possible that we're just on a very very very large (infinite?) curved surface of spacetime that just looks flat to us..
I would bet on it in fact. It makes logical sense to from my perspective.
I'm no way an expert in this, but I've been told it's wrong to think of the expansion of the universe like an explosion where everything moves away from a single point, but rather that the space between each object is expanding, comparing it to the way the surface of a balloon expands (if you were to paint multiple dots on the surface of a balloon they would all move away from each other when you inflate the balloon), though I like to think of it as yeast bread expanding since that's 3d.
Have you considered the universe may actually be a torus instead of a sphere, eg: bagel-verse?
Dodecahedron. Fight me
Yes that sure is an option, but it doesnt fit in my pastry-centric theories of the universe.
Spherical? We don't know if the universe is of finite size.
As far as we know, it could just as well be infinite, and the expansion happens everywhere.
Everything is relative so the only thing we know is that the distance between galaxies increases. But we don't know if there's a “border” of the universe or not.
The big bang (if it is still a valid theory) would have been unlike any explosion you have ever witnessed. The big bang was not an explosion of only matter, since time and space were both created during this event as well.
Really, calling it an explosion is not right in the first place. It's one of those unfortunate cases of bad naming in science, another being 'The God Particle' (which was originally supposed to be The Goddamn Particle.) Physicists prefer using the word 'expansion.'
I think it gets more spherical the larger it gets. The initial explosion from nukes are fairly spherical if you look at the old film. https://www.npr.org/sections/pictureshow/2010/09/28/130183266/abomb
One of the images from that slideshow begs to differ.
I like the donut universe.
https://www.livescience.com/the-universe-might-be-shaped-like-a-doughnut-not-like-a-pancake-new-research-suggests
There's some interesting ways of understanding "dark energy." This is just one.
I feel (intuitively (which is almost certainly wrong)) that it's expanding like a fluidic wave. Think lighting a gasoline puddle on fire.