Well, it depends on how you define “getting bigger”. Distances between pairs of points in the Universe are increasing, and if that were happening for any finite object, we’d have no problem saying that the finite object was getting bigger. Does this definition of “bigger” extend to infinite objects? Well, maybe.
Part of this is that we have the joy of living in a time when discoveries are being made.
Plate Tectonics, for instance: fifty years ago, we didn’t know how the earth worked. We didn’t know why there were mountain ranges and deep-sea trenches. Now we do.
The extinction of the dinosaurs: fifty years, we didn’t know why they died off. Now we do.
Cosmology is changing, because of new data from the Hubble telescope, and from infrared telescopes, and from microwave telescopes. It’s great! We’re learning.
This is always tough for people who learned one thing, and now have to “unlearn” it. I learned that Special Relativity meant that objects got “more massive” as they travelled really fast. Now, I’m told they don’t use that model any more, but talk about an increase in energy, instead. Okay… Just means we have to work a little harder to keep up.
You know what, I would be okay with that. But what I’m not seeing is an acknowledgement that, yes, 20 years ago we used to think A, but now we know it’s B. It’s more like, it was always B, and you must have been confused somehow.
Sorry, that sounds more complaining than I intended. Nobody needs to acknowledge anything. It’s just that it feels strange to discover that something you always thought was the case suddenly isn’t the case, and apparently never was.
Rotation is about an axis, but that’s not what ‘relative’ means.
Two objects in motion - one travelling due north at 100mph, the other, due south at 50mph. It’s perfectly valid to have a reference frame in which one is considered stationary, whilst the other moves at 150mph, or another frame in which they are each moving at 75mph, or another in which one is moving at 1,000,000 mph and the other at 1,000,150mph, and so on. Furthermore, these frames are not only valid, but absent any other reference points, you can’t even tell which one is really true (they all are).
The same is not true of rotation. You can’t define a reference frame in which the Earth is stationary, and the universe is rotating about it, because that requires geostationary satellites to be staying up there for no reason at all. (not to mention also requiring distant objects to be making circuits of the universe at vast multiples of the speed of light)
Predicting OP creationist agenda disguised as innocent question to emerge around post #50 after extended silence, as prescribed in Creationist Promotion Techniques 101.
I apologise sincerely to the OP if that’s not the case, but that’s exactly what’s happened in the last 50 or so such threads starting with an innocent question about cosmology. It kinda feels like a spam campaign. If I’m wrong, I’ll put my hands up and plead guilty and apologise personally.
“Shut up and calculate” right. One thing I don’t understand though is how physicists can draw any conclusions from the math at all. How do you go from numbers on a page to “this implies the universe has no edge”? Is there a way of describing that process to a layman or does it involve doing something incredibly complex?
They’ve a 2002 registration date and no apparent creationist agenda; in 2005 they referred to themselves as a “confirmed atheist”.
No worries. But… I don’t know of any science writers who would ever say that! Isaac Asimov is one of the greatest ever science writers, and he always emphasized the role of discovery. Just as I did in my post, re Plate Tectonics and the dinosaur-killing asteroid event. We didn’t know about these things until recently. We didn’t know about the expansion of space until Edwin Hubble noticed that nearly all galaxies had an unbalanced red shift. It took a few decades, but it led to the Big Bang Theory.
Anyway who says “We should have known about the Big Bang prior to 1900” is totally full of tarantula gizzards. We couldn’t have known! The observational techniques didn’t exist!
I’m not saying you’re wrong in any way. I would venture to suggest that you may have had the misfortune to stumble upon some really bad science writers!
Thank goodness for that! I must admit, I’ve become really jaded with seeing the title of a cosmological question thread in the thread list.
To all of you I recommend The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos by Brian Greene.
The book’s theme, or really plot, is to enumerate that there are nine - yes, nine - mathematically distinct variations on the concept of a multiverse today. The brilliance of the book is that along the way Greene delves into every question that comes up here as threads along the way and gives the background, with tiny amounts of actual math.
So yes, he does talk about a flat universe that can be thought of as cylindrical (or, more exactly, that going off the left instantly returns you to the right, like the screen of an old video game). That’s probably not our universe, though.
And yes he talks about the implications of an infinite universe, and that a universe that is infinite must always have been infinite from the moment of creation and how that is possible, but also that when we talk about our universe we’re usually talking about the universe that must have been in contact with all parts of itself at the moment of creation (the visible universe, although some of it is not now visible) so it is meaningful to say that universe is getting bigger but is infinite simultaneously.
And yes he talks about the three possible types of curvature (positive, negative, and flat) and why the universe must be one of them and why they think it’s flat.
But he knows what he’s talking about and he still takes multiple chapters to lay this all out, one multiverse at a time. I’m sorry, but expecting to get understandable answers in a paragraph is simply impossible. Even though we have many real physicists on this site who are very good at explanations, including Chronos, the reality is that you on the other side have to have some level of understanding of the basics before making the leap to infinity. (And I definitely include me among you.)
None of it is intuitive. Much of today’s understanding is new. It’s not discontinuous from what was being said 20 or 30 or 40 years ago, but even the good popular science books back then didn’t talk about nine multiverses. Each one has its roots in work that is decades old, though. But also, the details, math, and meaning behind each one is heavily debated by top scientists. There is no current consensus and that makes it rough on those who just want an answer. It may be that 2 or all 9 types of multiverses are simultaneously true. If the Big Bang crogulated people, think of what nine types of multiverses will do to sound bites.
It turns out that reality is complicated beyond anything once imagined. There may never be a theory of everything that can be written on a t-shirt in place of E=mc[sup]2[/sup]. That’s not our loss; that’s our gain. But it makes for lousy message board paragraphs.
Non-solid objects which rotate tend to do so with inner layers rotating at different velocities than outer layers.
http://news.stanford.edu/news/2008/october29/sun-102908.html
Is there any evidence of one part of the universe “spinning” at a different rate than another place?
Apology accepted. I assure you I haven’t a creationist bone in my body and were I to find one I’d rip the bugger out. I must admit I’m a little puzzled. How does the rotation or non-rotation of the universe tie in with a creationist agenda anyway?
And thanks to all for the replies. I’m just a sucker for cosmological speculation and find it endlessly fascinating.
The general pattern is a seemingly innocuous question about cosmology (“is the universe expanding?”, “help me understand the Big Bang”, “what’s redshifting all about?”, that sort of thing). A load of people go out of their way to answer it, and often put in quite a bit of effort. After a couple of pages, the OP starts arguing with them about the physics (mainly nonsense - they don’t understand the scinetific theory, so their arguments against it aren’t real arguments); and then, a bit later, they start slipping in creationist or intelligent design rhetoric. After a while, it’s a creationism/ID discussion thread instead, which was presumably the original aim, and so Mission Accomplished.
I don’t know why they disguise it like that. It’s not like they’re prohibited from posting threads based on their beliefs, and there’s nothing wrong with doing so (however much others might disagree with those beliefs).
There’s also sometimes an aspect of “Scientists don’t know the precise details of one particular fine point, ergo, everything scientists say is 100% wrong”. Or even “I personally don’t know the precise details, ergo, the scientists are wrong”, like Jack Chick thinking that the Strong Nuclear Force is Jesus.
But in my experience, most questions about cosmology (at least at a board like this one) are sincere.