Anyone here an expert on Scalar-Tensor-Vector Gravity (STVG), Tensor-Vector-Scalar Gravity (TeVeS) or f® gravity?
I took an undergrad course in stargazing, so I’m basically an expert in… whatever that is…
Prof was a big spectroscopy nerd, so we mostly focused on that.
What I gather from this article is that we still don’t know what dark energy is. We haven’t for decades. So the new telescope has failed to enlighten us about a mystery that’s been around longer than half of the users here.
Maybe Maybe there’s something seriously wrong with the Universe? Why is it always US who are wrong?
The universe is, frankly, a complete shitshow.
I’ve heard this has made many people very angry and is widely regarded as a bad move
I mean it’s got some valid points but let’s not get ahead of ourselves.
Hey, it’s me, the Universe. I just wanted to say, this is no longer working for me. And if it makes you feel better, sure it’s not you, it’s me. Please don’t call.
I like to think that whenever we discover something new, the universe just got an update and we discovered the patch notes.
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.
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.
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.
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!
It just wraps around, like a videogame. Duh…
It’s because CMB stopped for coffee, obviously.
(That was a great explanation, btw.)
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 on the surface of the 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
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.
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.’
There’s some interesting ways of understanding “dark energy.” This is just one.
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 feel (intuitively (which is almost certainly wrong)) that it’s expanding like a fluidic wave. Think lighting a gasoline puddle on fire.
What are the different rates? How much variance is there?
From memory it varies between about 67km/s per megaparsec to 74km/s per megaparsec.
Also it’s really weird to describe something in terms of km/s when you look at an area over millions of lightyears
Those are weird units indeed :
(1 km /s) / 1 mega parsec =
(1000 m/s)/(106 x 3.0857×1016 m) =
1/3.0857×1019 seconds =
1/978 x109 years.So, when we multiply by the rates (which are either 67 or 74) we get :
1/ 14.6 giga years or
1/ 13.2 giga years
… basically ( 1/ “age of the universe”).Meaning physical observation disagree about the age of the universe …or the theory is faulty.
Dogulas knew:
I always said there was something fundamentally wrong with the universe.
– Arthur Dent, the Hitchhiker’s Guide to the Galaxy Radio Series.
Sounds more like Arthur knew…
It’s like the stars when observed at veryx2 far distance they start to behave weird. Blinking a bit faster than normal this might cause the reason for much faster expansion when calculating. Entropy suppose to be improbable right but at far distance all those improbable they probably all eventually add up. Just my thought anyway.
Have you ever had a dream that
That you, um, you had, you’ll, you would
You could, you do, you would you want you
You could do some, you…
You’ll do, you could you, you want
You want him to do you so muchYou could do anything, do anything
Have you ever had a dream
You could do anything, do anything
Have you ever had a dream
You could do anything, do anythingLmao
Perfect!
“The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny…'” --Isaac Asimov
TIL Columbo was the ultimate scientist.
“Oh, just one more thing…”
The scientific spirit at work!
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.
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.
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
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.
Yay!
We have a very limited view of the universe so it’s no surprise that our theories are often wrong or incomplete. The beauty of science is that when a theory proves inadequate, it gets replaced with a more complete one.
It’s always funny to me when people bring up how science was wrong in the past, as evidence for why we shouldn’t trust it now.
You know what replaced the bad science? Good science.
Or rather, we replace the bad science with the best explanations we can offer, right now.
I’ll take the plumb pudding model over “deity did it, stop asking questions” any day, because you can still do something useful with it.
Doesn’t even matter if our understanding is wrong and will be updated later.
Science is the best philosophy 💪
I’ve always liked the adage: science doesn’t tell us what’s true, only what isn’t.
We don’t know the best way to treat cancer, but we know leeches don’t work.
yeah, but it’s always a shitshow when someone brings alternate theories to the big bang. it’s almost like back in those days when they burned people for suggesting the earth may be slightly less flat than expected.
Don’t dare question dark matter in front of a physicist.
That’s because alternative models like MOND or string theory end up breaking more things than they solve. Fixing the leak in your roof is great, but doing so by breaking the living room wall isn’t really an acceptable solution.
Isn’t string theory basically dead at this point?
In optimization problems, you can get stuck at a local maxima. It looks like any direction you go makes things worse. But the only way out of that is to try something that does make things worse and try refining from there to see if you can get to something better. Maybe that living room wall does need to come down in the process.
TLDR: Depending on where we look, the universe is expanding at different rates. We can now confirm it’s not measurement error.
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!
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
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!)
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?
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?
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?
The Hubble constant seemed determined not to be constant.
Sounds like a quote from the Hitchhikers Guide
Get your freaking towel and get outta here, man!
Now that’s a hoopy frood who knows where his towel is
The Hubble Suggestion just doesn’t sound the same.
It’s called Webb-constant now.
