Member
Hello,
I came across this article while reading up as suggested in another post. Can someone help explain this in layman terms. The title says something wrong with the universe as in a bad way but the article mentions no worry and pycisists are intrigued. So is something wrong or not?
Thank you
https://www.google.ca/amp/s/www.wash...outputType=amp
Established Member
The link doesn’t work.
ETA: try this
https://www.google.com/amp/s/www.was...outputType=amp
Member
Established Member
Ok so it’s a story about the Hubble Constant and efforts to refine the constant into a more precise value. The story discusses a few ways as to why the values are different.
It’s a news story so the writers needed a jazzy “hook” so they characterized the universe as “mysterious”. Typical for what passes as journalism these days.
Order of Kilopi
Dumb title. There's nothing wrong with the Universe. There's something incomplete about our understanding of how it's expanding.
Grant Hutchison
Member
So why does the article talk about something wrong and things like that. For someone like me who is clueless it makes me feel like we are ducked
Example
The universe doesn’t look right. It suddenly looks . . . out of whack.
That is the strange message coming from astronomers and physicists, who are wondering whether they need to revise cosmic history.
Order of Kilopi
Because they're journalists, and they want you to click on the link. Which is more like to make you click: "Something Is Wrong With The Universe" or "We Still Don't Fully Understand The Universe"?Originally Posted by Sinbad
Grant Hutchison
Member
Thanks this also confused me with wording
So the disparity persists. That leaves open, Riess said, the tantalizing possibility: “No one’s wrong. Something else is going on in the universe.”
Also can you explain to me how the article specified is not something wrong but that we don’t understand it?
Last edited by Sinbad; 2019-Nov-12 at 10:02 PM.
Order of Kilopi
I don't understand what you're trying to say here. In particular, the French word étui doesn't seem to belong in the last sentence.
Grant Hutchison
Member
I fixed it my keyboard on my phone likes flipping.
What I meant was how can you read that article and understand that they are not Implying something is wrong but are stating that they need a better understanding
Order of Kilopi
There are a couple of more detailed (and serious) articles here:
https://www.forbes.com/sites/startsw...o-new-physics/
https://www.quantamagazine.org/cosmo...ding-20190808/
It may be an indication of something we don't understand, and maybe some new physics is required to explain that. But some cosmologists still think that the measurements need to be improved.
Watch this space (and watch out for dodgy headlines).
Last edited by Strange; 2019-Nov-12 at 10:46 PM. Reason: no idea what I meant
Member
Thank you for better links, what did you mean about improved and concerned
Order of Kilopi
This is a science article. Science never says that there is anything wrong with the universe! The universe is always right. Our models of the universe can be wrong. So any implication that the universe is wrong is journalism, not science.
Scientists are baffled: What’s up with the universe? has quotes from scientists saying that a better understanding is needed. New physics could alter the cosmological measurement of Hubble's constant to agree with "local" (from galaxies, etc.) measurements. Some results that disagree with both may be flawed (or correct and the other measurements are flawed!). The "local" measurements may change as we develop a better and more accurate cosmic distance ladder.
ETA: The news is that there is a conference on the Hubble constant tension with some new results. The Hubble constant tension itself has existed maybe since the CMB data was first analyzed to get the Hubble constant. The expectation was that as more accurate data came in with better analysis, the values would merge. A year or two ago it became clear that there were at least 2 distinct, not overlapping values.
Last edited by Reality Check; 2019-Nov-12 at 10:31 PM.
Order of Kilopi
Because that's what the article says, all the way through. Either some of the measurement techniques are wrong (for reasons we don't understand), or they're all correct measurements but their disagreement is telling us something interesting about the Universe (which we don't understand).
Grant Hutchison
Order of Kilopi
I have no idea. "Concerned" must have been an autocorrection of something, but now I don't know what! (Constrained? Concentrated? Constipated?)
Order of Kilopi
I think there's something more going on here than just journalistic license to try to increase drama. I think what we're seeing here is an all-too-commonly promoted misunderstanding about what science is. Many articles seem to stress that the universe must be governed by simple laws, kind of an "Occam's Razor" gone mad, and when you think the universe must be governed by simple laws, you think our job is to find those laws. So when we do find them, if we later discover the universe isn't following those laws, then the universe is doing something wrong-- it is "out of whack." That's such a mischaracterization of the relationship between science and the universe, that I'd say it does more harm to our understanding of the universe than it helps to notice that there is potentially something interesting going on that we haven't figured out. But of course there's something interesting going on that we haven't figured out yet, that isn't a problem with our science it is literally the definition of science.
Member
That went completely over my head Ken
Order of Kilopi
Or, to quote Neil deGrasse Tyson, "The Universe is under no obligation to make sense to us."
Order of Kilopi
Science is not in the business of providing simple answers. Science is asking questions, and examining the Universe to see if we're asking the right questions.
"I'm planning to live forever. So far, that's working perfectly." Steven Wright
Order of Kilopi
What I mean is, we don't want to make the mistake of thinking that it's the universe's job to be simple for us. We don't want to fall into the trap of imagining our relationship with the universe is like when we are parents and we lay out some simple rules for our kids, simple enough for them to follow easily, and then if they don't, we say they are misbehaving. Yet that's the mindset of the article you cited, which fails to see the key difference: the parent is choosing simple rules on purpose, and in science, we do something similar, but we are just looking for simple rules-- the universe is not misbehaving (or "out of whack") if it does not choose to follow said rules. We are not its parents, we are its children, and science is not about imposing our designs on the universe. It is about us trying to understand the universe by looking for rules we can understand, but expecting that the rules will likely be more complicated than that (which means scientists never run out of work!). The issue is that it is necessary to say all this-- because this is basically not at all the way science is often described in school and the media, it is made to seem (as the article tries to do) like science is imposing rules on the universe that it could be "out of whack" if it doesn't follow. Just think for a moment about what it means for us to imagine our relationship with the universe is to be its parents rather than its children! What trouble could a family get into when the children imagine they are running the show?
Last edited by Ken G; 2019-Nov-13 at 03:29 AM.
Order of Kilopi
You are completely misunderstanding what's meant by "something is wrong" and getting worried for something you don't need to be worried about. It's something that happens when you take new measurements. It's like a bit more than a hundred years ago, when somebody first took detailed measurements of the speed of light and found that "something was wrong," because it seemed to be the same in all directions, which didn't make sense to them. But then Einstein came along and gave a logical explanation for why it seemed odd, and now we understand. So it wasn't that something changed about the universe, but rather that the measurements were in conflict with what we assumed about the universe. And it's something like that that the article is talking about.
As above, so below
Order of Kilopi
Another analogy might be that of navigating around a strange town using a map. If we suddenly find that the features of the town don't match the features on the map, we don't suddenly declare that there's "something wrong" with the town. The town just is the way it is. We assume that either there's something wrong with the map, or with the way we're using the map.
Similarly, scientists don't declare that there's something wrong with the Universe when they discover it's not behaving according to current theory - they figure that they need to improve the theory, and/or better understand how to test the theory using experiments.
Grant Hutchison
Established Member
Some comments on the "Hubble constant tension".
It's real (the tension), but grasping what it actually is isn't all that straight-forward.
Very broadly, there are ~a half dozen, more-or-less independent methods of estimating the Hubble constant. Of these, ~three have "error bars"* small enough that the estimates are inconsistent, at the "several sigma" level. The other methods do not yet have "small" error bars (or no accepted estimates at all ... no observations!).
What's going on? Unrecognized systematics? Unrealistic estimates of "errors"? New physics? Something else? A lot of people are working on this. Pretty much full-time.
Three recent blog posts by telescoper (Peter Coles) are quite good; there are many others:
More Hubble Constant Tension
Gravitational Lensing, Cosmological Distances and the Hubble Constant
More Cosmic Tension?
* these are not your high school physics experiment error bars. One has to be very careful with them. These days they are spelled out in great detail, and are often compatible. In most cases they are based on very detailed analyses of the various sources of "error", and are actually distributions (which may or may not be Gaussian); the quoted "errors" are 1
Member
Can you explain what are error bars?
Order of Kilopi
Some people are convinced it *should* be simple and the fact that our models are getting ever more complex means they are wrong. That seems a crazy view to me.
It is remarkable that we are able to model the behaviour of the universe mathematically, sometimes using very simple math. But I don't know if that really means that the universe is "obeying" those mathematical rules; or if we just come up with these mathematical rules as reasonably good descriptions of what it does. And maybe this is why the math keeps getting more complex: because we doing so ever more complex "curve fitting" / epicycles to get a closer match between description and experiment.
But I then I think, "but why isn't it simpler?" Couldn't atoms just be made of electrons, protons and neutrons - with the latter being fundamental particles? Does the universe "need" quarks, neutrinos, etc? Why do they exist at all? (But they do, so we just have to try and describe them as well as possible...)
Order of Kilopi
Yes, that's probably the deepest question in physics, and there's no good answer in sight. People often talk about intelligence as a survival trait, but the kind of intelligence that is required to do quantum field theory never helped any cavepeople out of a tiger's den, as evidenced by the fact that abstract mathematicians are not known for being handy in tiger battles. More likely the ability to do advanced mathematics is purely a "spandrel" of the kind of intelligence that improves survivabiity, but the big question is, why are spectacularly successful physics theories such a short leap away from being smart enough to sharpen a stick?
Yet notice the subtle prejudice behind such a statement-- for atoms to really be made of electrons and so forth, wouldn't that require we mistake our models for the real thing? So your question basically comes down to asking, why doesn't the universe actually work the same as our models do? My answer to that would be, if our universe really did work exactly like our models of it, then the universe is very clearly a simulation, because that's essentially the definition of a simulation-- something that is really "governed by" some simple model. So we have this very interesting contradiction, that on one hand we want to imagine the universe really obeys a set of rules, and on the other hand, no one wants to think it's some kind of simulation embedded in some more complete universe. Yet those two things are just the same, you can't pick the one you want.ut I then I think, "but why isn't it simpler?" Couldn't atoms just be made of electrons, protons and neutrons - with the latter being fundamental particles?
Established Member
Say you want to know your weight, and have only an old scale (i.e. not a modern one with a digital screen). You step on, note the value, step off. And repeat.
The numbers you wrote down will, in general, be different from one another (though some may be the same).
How do you calculate your weight from these numbers? You take the average of them.
But how sure can you be that the average is your "true" weight? Or, put differently, from these numbers, what - realistically - could your "true" weight be?
To answer questions like this, you need to know how much your numbers differ from one another. One way to get an answer to that question is to calculate the "error bar". That gives you an idea of how much the numbers vary.
All this can be expressed in mathematical form. If you are interested, I (or rather someone else who can explain it better than I can) would be happy to explain further.
Note: for readers who understand this well, yes, the above is a simplification, and perhaps goes too far. If you think so, please comment.
Last edited by Jean Tate; 2019-Nov-15 at 01:51 AM. Reason: typo
Established Member
There's another aspect, emergence.
From models of what quarks and gluons (etc) do, how does one get atomic physics? chemisty? biology? geology? ecology? economics?
We think causation goes one way only (up), and AFAIK there is no evidence to the contrary.
Established Member
I haven't read any of the articles, but I expect it refers to a measurement, together with the level of uncertainty about the measurement.
If you make the same measurement repeatedly, you will get different results, because the measurement process isn't perfect - it has some random error. (Systematic error is much harder to deal with.)
The error bars (gross oversimplification coming up) are set so that the measurement will fall between the upper and lower error bar a certain percentage of the time. 95% is a common choice in some disciplines. So if you set your error bars based on a 95% level, then 95% of the time, the measurement will come between the upper and lower error bars. 5% of the time, it will come out either above the upper error bar or below the lower error bar. If your measurement process is very precise, then the upper and lower error bars will be very close together. If your process is not very precise, then the two error bars will be far apart.
The fact that the different studies have different results that lie outside of each others' "error bars" suggests that the discrepancies are probably not due to random variation in the measurement process, but some systematic problem. Maybe one of the methods is just wrong, for example.
Just to take a very simple example, if I were to measure the force of gravity at some point on earth's surface using two different methods, and I got two different numbers (9.832 m/s^2 vs 9.801 m/s^2), does that mean something is wrong? Well, if my measurements are not very precise, then the upper and lower error bars are far apart, and the difference could be due just to random variation in the measurement process. But if both of my measurement methods are very very precise, then the error bars will be very close together, and the fact that I'm getting two different answers suggests that most likely something is wrong with one of my methods.
Last edited by 21st Century Schizoid Man; 2019-Nov-14 at 06:23 PM. Reason: added "using two different methods" to last par
Established Member
Here's a graphic from Wikipedia that illustrates how error bars can look. This is just one example as there a various ways of applying the data to examine possible outcomes.
https://upload.wikimedia.org/wikiped...ceinterval.png
Posting Permissions
Reply With Quote