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Yay, progress!
But maybe the measurement methods are not correctly understood either, as profen by the brightness of white stars used to determine age, lately.
It’s almost like cephid variable measurement is a shitty metric for measuring universe expansion because you’re not actually measuring the edge of the universe just the rate of travel of two objects.
How can you measure the edge of the universe? Firstly anywhere you hold the tape you are in the universe secondly its expanding faster than the speed of light which is a limit for movement without space not the expansion of space.
TLDR: Depending on where we look, the universe is expanding at different rates. We can now confirm it’s not measurement error.
It’s not a matter of where we look, it’s the method we use to calculate the expansion. The 2 methods to calculate the expansion rate give us different results. For a good explanation, here is a YouTube playlist of videos by Dr. Becky Smethurst where she discusses & explains the “Crisis in Cosmology”: https://www.youtube.com/playlist?list=PLd19WvC9yqUf5TRqYoMYxEwjT6JIDW4Zn
Oh. Well. That’s. Terrifying?
don’t worry, we’re expanding with it!
I’m not expanding! It’s just my big bones, y’know!
Uh, why?
I’m afraid of things I can’t understand.
You can make a religion out of that!
Good riddance, the answer can never be too simple.
The human need for ‘constants’ may already be too simple. Gravity for example is treated as a constant value in Physics but is actually variable.
Your understanding of what constitutes “Physics” (tip: it’s not a bunch of kids in a classroom) tells me that we can safely ignore your opinion.
I might have missed something, but AFAIK, gravity is the same everywhere. Bigger things, bigger gravity, sure, but two equal things in different locations don’t have different gravitational attraction
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The
cakeBigBang is a lie.
original source :
https://iopscience.iop.org/article/10.3847/2041-8213/ad1dddsee also :
https://en.m.wikipedia.org/wiki/Hubble’s_law
Hubble tension
In the 21st century, multiple methods have been used to determine the Hubble constant. “Late universe” measurements using calibrated distance ladder techniques have converged on a value of approximately 73 (km/s)/Mpc. Since 2000, “early universe” techniques based on measurements of the cosmic microwave background have become available, and these agree on a value near 67.7 (km/s)/Mpc. (…)
(…) The most exciting possibility is new physics beyond the currently accepted cosmological model of the universe, (…)Can someone give me the spark notes I started reading but I’ll never get through that or probably even understand all of it
As I understand it, there are two measures of cosmic distance/expansion rate in which we are pretty confident.
One is using supernovas as a measure. Since one kind of supernova has very particular characteristics, it is easy to calculate the distance. It is like knowing that everyone has the same kind of candle, if you see a bunch of lights around you, you could make certain assumptions about how far they are from you by how bright they are. Also, with more precise measurements, we can use the doppler effect to know how fast they are moving. We have observed the area around or Galaxy and have come up with a very precise measurement for how fast the universe is expanding.
The other measurement is by looking at the cosmic wave background. This is the “first” thing we are able to see after the big bang. I don’t really understand the details of this one, but scientists have also been able to calculate the expansion rate of the universe very accurately with this radiation.
As we have done more experiments to measure these two numbers, instead of converging on the same number, the results are actually diverging. Recent results have even made it so the error bars no longer overlap.
So, we have some big questions -
- Are our measurements wrong? There are no strong candidates for alternative understandings of how we measure things, so we don’t really know how.
- Are the expansion rates at the beginning of the universe and current times different? Maybe, but again, we don’t have any theories for why.
- Does the Universe expand at different rates in different places? Maybe, but again, we don’t have any strong candidates that we can test.
All of this is called the Hubble Tension. It is probably one of the biggest questions in cosmology currently.
Thanks this is both an uncomfortable and exciting thing to read.
It’s simple, imagine you’ve got two smart friends that both have an opinion about a TV show you didn’t watch - you can’t tell who is right but the fact they disagree suggests they might be wrong when they say you can’t have flying cars and time travel.
Basically,
Everything you know is wrong.
Black is white, up is down, and short is long
I wish I had more upvotes for the random Yankovic!
And everything you thought was just so important doesn’t matter. Everything you know is wrong. Just forget the words and sing along. All you need to understand is, everything you know is wrong.
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One day science will reach the Orphic understanding of the origin of the Cosmos.
Well, maybe at least this version:
Next after them, Epicurus introduced the world to the doctrine that there is no providence. He said that all things arise from atoms and revert back to atoms. All things, even the world, exist by chance, since nature is constantly generating, being used up again, and once more renewed out of itself—but it never ceases to be, since it arises out of itself and is worn down into itself.
Originally the entire universe was like an egg and the spirit was then coiled snakewise round the egg, and bound nature tightly like a wreath or girdle.
At one time it wanted to squeeze the entire matter, or nature, of all things more forcibly, and so divided all that existed into the two hemispheres and then, as the result of this, the atoms were separated.
- Epiphanius of Salamis, Panarion book 1 chapter 8
Very fun in the context of Neil Turok’s CPT symmetric universe theory as an explanation for the baryon asymmetry problem, so its discussion of matter being squeezed and then splitting into two which divided the particles may end up on point even if incorrect in their interpretation regarding the atmosphere.
Over and over again. That scope is really opening things up.
It was the same for the Hubble telescope back in the day (and still!)
Why couldn’t this still be “big bang”? Look at a grenade for example. When it explodes, a shock wave expands from it in a near perfect sphere, but the fragments previous packed inside of it explode out at different speeds depending on their mass.
If you were in the center of that explosion, measuring the speed of fragments traveling away from you, they’d travel at different speeds. Only the initial shockwave would be constant.
Maybe because the speed of things is not the same thing as the speed of space expansion.
This is more like you measure the fragment speeds with both a laser and with radar, and get different readings off the same fragment.
This problem is not AT ALL about the geometrical shape of the expansion of the universe. It’s about 2 different formulas that should give the same result for the rate of the universe, but give different results. I don’t blame you, the article title is extremely misleading.
Seeing the universe expanding at different rates could just mean we’re not as close to the center as we thought, and the parts further away from the center are moving faster. That’s my layman’s hypothesis though
There is no center of the universe fwiw, there is no middle everything is expanding out from. Just a substrate that exists everywhere that inflates
It’s fun to think it might just start going backwards or something because we have literally no idea what is actually happening, like it’s very possible we’ll never actually be able to see or measure anything outside the universe but there could be all sorts of things going on.
That’s what I believe as well. AFAIK from what we know the universe could be infinite or simply bigger than the observable part. But I think the only reason people default to assuming that it’s finite is that infinity is hard to grasp and that illustrations of the big bang show a point and then disks of expanding size. People assume that means the universe is a sphere but nothing contradicts what you say so there’s no reason not to believe that it’s infinite.
There is no center.
Yes there is and it is me.
Can I have some money?
Loose the centre assumption and you are there.
Our section of the universe is not as uniform as it should be.
When people are talking about the center they mean the relative center, in other words, our point of reference. This definitionally is where we are as the observer.
We’re not thought to be at the center at all.
We’re at the center of what we can see. But that’s just a limit of the speed of light and the age of the universe. The universe almost certainly goes beyond what we can see. And there’s no way of knowing how big the universe is beyond that.
It’s like being on a ship in the ocean. You can see the horizon is 20miles in every direction. That doesn’t mean you’re in the center of the ocean. You’re only in the center of what you can… Sea
I sea what you did there. Whale done.
Kurzgesagt’s latest video actually covers this. I found the hypotheses they covered pretty interesting.
It’s a decent testable hypothesis. If there were a center. Which seems obvious in the familiar mechanical way of say a firecracker. It certainly has a center with debris going every direction from that point.
However (to use a problematic oversimplification): what if the universe has a similarity to the surface of a balloon being blown up, where is the center?
Wherever you put your finger, the whole rest of the surface of the balloon is expanding away from that point. One center point is earth. Every other place in the universe also appears to be a center.
When looking at the evidence, data from telescopes and such, describing the expansion of the universe is closer to the balloon surface theory than the firecracker theory. Even though the firecracker theory is easier to comprehend.
Yay!
Is it capitalism? Please let it be capitalism.
Do you ever take a break from the political stuff? Seriously man…. Take a rest.
I didn’t know you cared.
About you? I don’t. But I care about all the others that have to be annoyed by this shit. This isn’t a political post. How about taking a break and just enjoy things for what they are instead of your usual attempts to manufacture arguments.
Says the person who took the bait 😆
You think this was me taking bait? Nope. This is just calling out a troll.
Shill*
They consistently parrot russian and chinese talking points under the guise of being objective
Gotta be careful what you call them. They can get you banned.
I hope not, politics define almost every single moment of our existence. It’s like physics, but with more assholes.
Yay! We are learning something new!
This is what I was very very excited for. The Hubble photos were more exciting because they’re visual spectrum. The James web is all about discoveries.
But moooom, I hate learning new things
From my limited understanding, the discrepancy comes from the two ways to measure the universe’s expansion: calculation from cosmic microwave background and calculating a cepheid variable, which uses pulsating stars (pulsars?)
Isn’t it more likely that one, or both, ways of measuring are wrong? As in, they’re not useful for measuring the universe’s rate of expansion?
Isn’t it more likely that one, or both, ways of measuring are wrong? As in, they’re not useful for measuring the universe’s rate of expansion?
Now, scientists using the James Webb and Hubble space telescopes have confirmed that the observation is not down to a measurement error.
I’m trying to understand the distinction you are making. Could you elaborate?
Not a scientist but the article seems to mean that they checked that the tools themselves had no defects giving incorrect measurements.
This comment seems to be questioning the methodology of how we measure the rate of expansion so tackles a different aspect of the conversation.
But that’s about as much as I can contribute haha
Pretty much this. In a (hopefully) more direct metaphor, are we sure we’re using a ruler to calculate the length of a line, and not using a ruler to calculate the temperature of a paper?
I think the distinction is between arguing that there’s a discrepancy because the measurement is bad, or because the measurement doesn’t measure what we think it measures.
Is the theory right and we have a measurement error, or is the theory flat out wrong?
The model is wrong. Get hype
