Universe Expansion And Galaxy Collisions

[TheeGoatPig]

There are lots of astrophysical theories being posited by a lot of people on a myriad of subjects. One of them is the Big Bang theory. Not the TV show, but the actual theory that all matter in the universe used to take up the space of a grain of rice, and then exploded into what we now see as the night sky. stars, planets, black holes, all came from this one event around 13.7 billion years ago. Throw in some dark matter and dark energy (forces that cannot be explained by modern science), and most scientists agree that the universe is still expanding at an accelerated rate in all directions, with every bit of matter moving steadily away from all other matter, expanding the universe to the point where gravity from one particle will someday cease to have any discernible effect on the particles around it.

So if the universe is expanding in such a way, and all matter is moving away from each other, how do galaxies collide with each other? You would think that they were all ready so far apart that their individual gravities will only have a tugging effect on each other, and that collisions would be a thing of the billion years ago past. And yet it is still happening.

It's times like this I wish I knew Neil Degrasse Tyson.

 

[TxRad]

There are lots of astrophysical theories being posited by a lot of people on a myriad of subjects. One of them is the Big Bang theory. Not the TV show, but the actual theory that all matter in the universe used to take up the space of a grain of rice, and then exploded into what we now see as the night sky. stars, planets, black holes, all came from this one event around 13.7 billion years ago. Throw in some dark matter and dark energy (forces that cannot be explained by modern science), and most scientists agree that the universe is still expanding at an accelerated rate in all directions, with every bit of matter moving steadily away from all other matter, expanding the universe to the point where gravity from one particle will someday cease to have any discernible effect on the particles around it.

So if the universe is expanding in such a way, and all matter is moving away from each other, how do galaxies collide with each other? You would think that they were all ready so far apart that their individual gravities will only have a tugging effect on each other, and that collisions would be a thing of the billion years ago past. And yet it is still happening.

It's times like this I wish I knew Neil Degrasse Tyson.

Simple answer: The galaxies are moving at different speeds and some at different angles due to blackholes among other things. Some overtake others or end up on collision courses.

 

[mynameisben]

My father drove a Galaxy until it was hit by a Comet.

 

[TxRad]

My father drove a Galaxy until it was hit by a Comet.

What do you get when you cross a Pontiac with a Mustang?

Poontang, of course.

 

[Handley_Page]

There are lots of astrophysical theories being posited by a lot of people on a myriad of subjects. One of them is the Big Bang theory. Not the TV show, but the actual theory that all matter in the universe used to take up the space of a grain of rice, and then exploded into what we now see as the night sky. stars, planets, black holes, all came from this one event around 13.7 billion years ago. Throw in some dark matter and dark energy (forces that cannot be explained by modern science), and most scientists agree that the universe is still expanding at an accelerated rate in all directions, with every bit of matter moving steadily away from all other matter, expanding the universe to the point where gravity from one particle will someday cease to have any discernible effect on the particles around it.

So if the universe is expanding in such a way, and all matter is moving away from each other, how do galaxies collide with each other? You would think that they were all ready so far apart that their individual gravities will only have a tugging effect on each other, and that collisions would be a thing of the billion years ago past. And yet it is still happening.

It's times like this I wish I knew Neil Degrasse Tyson.

I'd like to know; "If the universe is still expanding, into what is it doing it?"

 

[TxRad]

I'd like to know; "If the universe is still expanding, into what is it doing it?"

Into a realm of dark matter, The same stuff that fills in the regular universe.

The whole explanation took an hour on science channel to explain and it was a while ago that I watched it.


Edited to add: This is just theory since we can't really see the edge of the universe from where we are. Our galaxy is young and we don't have telescopes to see far enough to the edge.

 

[fuckwaffle]

The universe is infinite and infinity is growing all the time. Huh!

 

[soflabbwlvr]

Before you can intelligently discuss this idea, you need to get a good grasp on the concept of "Space-time." The best, easiest to follow discussion I have seen was presented in the season one finale of "The Universe." I can't find a complete episode on line, but here is a link to the summary of that episode. Universe. The Season 1 box set is available on DVD and Blu-ray, but that is more than you really need.

 

[lance gt]

The new theory is there are multiple universes that exist on different planes of frequency. We exist on one frquency and everything feels real, because we can touch and see it. These other universes are operating at different wave lengths and exist in the same space as us, but at a frequency we aren't able to see or touch. Much like radio stations that operate at different frequencies.

 

[dr_mabeuse]

There's no way of knowing what's beyond the farthest galaxies, just like there's no way of knowing what came before the Big Bang.

I don't mean that it's a big mystery and it might be full angels dancing on pins or something. I mean that it's simply unknowable. Our science and physics can only deal with matter and energy. Matter and energy define space and time. Space is the distance between matter, and time is motion through space. Without matter and energy, the concepts of space and time simply have no meaning.

The interesting question is which is bigger: the universe or our ability to understand it? When you get to the limits of the universe, I think our ability to conceptualize fails.

 

[lance gt]

The only thing they do know, is where it started. They put everything in reverse and saw where it started from, so they know the point of origin, but after that, it's a crap shoot to what has happened. They know our galaxy is on a collision course with our neighbouring galaxy, but not for millions of years yet to come.

 

[mynameisben]

The new theory is there are multiple universes that exist on different planes of frequency. We exist on one frquency and everything feels real, because we can touch and see it. These other universes are operating at different wave lengths and exist in the same space as us, but at a frequency we aren't able to see or touch. Much like radio stations that operate at different frequencies.

"The New Theory," huh? Is there any tangible evidence to support TNT? Just because something can be conceptualized doesn't make it a theory. At best, TNT is a crackpot hypothesis.

I can hypothesize that beyond the knowable limits of our universe there is a porno paradise, where males bristle with ten trillion penises, and female is Space. Female Space is a unified, pulsing vaginal infinitude that engulfs everything within the unreachable universe in which it exists. Time has no meaning there, because the entirety of that unreachable, undetectable and unknowable universe is in a constant state of orgasm, having no beginning and no end. And you can't prove my hypothesis wrong, because you have no means of detecting such a universe, not now, not ever. I could even call my hypothesis a "theory," but if tangible evidence is so lacking that no one else buys into it, I'm merely raving to myself.

I'm not saying the existential tunable frequency model of the interwoven multiverse cannot be. All I'm saying is, show me the radio.

 

[TxRad]

"The New Theory," huh? Is there any tangible evidence to support TNT? Just because something can be conceptualized doesn't make it a theory. At best, TNT is a crackpot hypothesis.

I can hypothesize that beyond the knowable limits of our universe there is a porno paradise, where males bristle with ten trillion penises, and female is Space. Female Space is a unified, pulsing vaginal infinitude that engulfs everything within the unreachable universe in which it exists. Time has no meaning there, because the entirety of that unreachable, undetectable and unknowable universe is in a constant state of orgasm, having no beginning and no end. And you can't prove my hypothesis wrong, because you have no means of detecting such a universe, not now, not ever. I could even call my hypothesis a "theory," but if tangible evidence is so lacking that no one else buys into it, I'm merely raving to myself.

I'm not saying the existential tunable frequency model of the interwoven multiverse cannot be. All I'm saying is, show me the radio.

The naked lady put her hands over her breasts and gave Ben a hard stare. "Don't even go there, short stuff. You ain't touching my knobs."

 

[dr_mabeuse]

The only thing they do know, is where it started. They put everything in reverse and saw where it started from, so they know the point of origin, but after that, it's a crap shoot to what has happened. They know our galaxy is on a collision course with our neighbouring galaxy, but not for millions of years yet to come.

Well, they don't really know "where" it started, because when it started, there was no "out there" to locate it in. Space was created in the same instant as matter. Before that there was nothing, Ain Soph, the Great Unknowable.

The other dimensions they talk about aren't based on frequency, because we know all about frequencies of radiation, and we can scan them all. Frequency is a measure of how fast something moves in space, and "thing,", "move" and "space" are all a firm part of this universe.

The idea of extra dimensions is best explained through analogy. Imagine a world of 2-dimensional beings, who all live in the plane of a piece of paper. That's all they knew, that plane of paper. They can move to and fro and back and forth, but they have no conception of up and down out of the plane of the paper. They'd see each other as lines, and they could move around, but only in that plane. They live in a 2-dimensional universe.

And now you come along from your 3 dimensions and look down at them and you can see inside them. You can see all of them at once. You try and explain to them that you come from a 3rd dimension but they can't wrap their little 2-D minds around it. You tell them your 3rd dimension is at right angles to their world, but they can't imagine what that means.

Similar to that, extra dimensions would be at "right angles" to our 4-D world. We couldn't see them or even imagine them, anymore than the little 2-D people could imagine 3 dimensions.

The only reason we have any reason to believe they might exist is because of mathematics. There are apparently ways to describe all of nature mathematically in terms of an 11-dimension universe. But even though the equations work, no one has any idea of what 11-dimensions means. It's just beyond our capacity to imagine.

 

[lance gt]

Well, they don't really know "where" it started, because when it started, there was no "out there" to locate it in. Space was created in the same instant as matter. Before that there was nothing, Ain Soph, the Great Unknowable.

The other dimensions they talk about aren't based on frequency, because we know all about frequencies of radiation, and we can scan them all. Frequency is a measure of how fast something moves in space, and "thing,", "move" and "space" are all a firm part of this universe.

The idea of extra dimensions is best explained through analogy. Imagine a world of 2-dimensional beings, who all live in the plane of a piece of paper. That's all they knew, that plane of paper. They can move to and fro and back and forth, but they have no conception of up and down out of the plane of the paper. They'd see each other as lines, and they could move around, but only in that plane. They live in a 2-dimensional universe.

And now you come along from your 3 dimensions and look down at them and you can see inside them. You can see all of them at once. You try and explain to them that you come from a 3rd dimension but they can't wrap their little 2-D minds around it. You tell them your 3rd dimension is at right angles to their world, but they can't imagine what that means.

Similar to that, extra dimensions would be at "right angles" to our 4-D world. We couldn't see them or even imagine them, anymore than the little 2-D people could imagine 3 dimensions.

The only reason we have any reason to believe they might exist is because of mathematics. There are apparently ways to describe all of nature mathematically in terms of an 11-dimension universe. But even though the equations work, no one has any idea of what 11-dimensions means. It's just beyond our capacity to imagine.

They had the expansion run backwards and found the point of origin, and as you say, where and what it started from is a mystery. Those in the know with the credentials, have supposed and theorized through probabilities, that other dimensions exist, because of the Black Holes that are present. They opine that another reality exists on the other side, because of the anti-matter, that destryos our matter. Because energy can't be destroyed, they theorize it is transformed. There's as many theories, as there are astro-physicists, but things are making more sense, because of them.

We're only aware of frequencies we can produce, or have equipment to measure, so how many more frequencies could be present? What's present in those frequencies? This is what the speculation is leading to. One thing they do know, is the expansion is speeding up.

 

[BONNIEBREA]

So if the universe is expanding in such a way, and all matter is moving away from each other, how do galaxies collide with each other? You would think that they were all ready so far apart that their individual gravities will only have a tugging effect on each other, and that collisions would be a thing of the billion years ago past. And yet it is still happening.

It's times like this I wish I knew Neil Degrasse Tyson.

I have a general, layperson's interest in the sciences, and had occasion to wonder about this, too.

The answer is that, although the fabric of space-time is expanding (the usual analogy is the skin of a balloon expanding as it is inflated, with every point on the surface getting farther away from every other point with each new added puff of air), that expansion does not overcome local gravitational attractions. Groups of astronomical bodies interact gravitationally in a way that is not associated with the expansion of space-time.

Think of the Earth-Moon system. The two bodies are so close together that any expansion of space-time between them is negligible. The Moon just orbits the Earth,or, more accurately, the two bodies orbit a common center of gravity, although that center is located inside the Earth. The Moon doesn't expand away from the Earth in a way that is more profound than the gravitational attraction keeping the two bodies together.

On a larger scale, the local group of galaxies (fifty-some of them, with the Milky Way (our galaxy) and the Andromeda Galaxay being the largest two) also interact gravitationally in a away that is more profound than the expansion of space-time. In fact, in about 4 billion years the Milky Way and Andromeda will "collide" into one another and eventually merge into one much larger galaxy. The "collision" will almost certainly not result in any spectacluar stellar collisions since the space between stars is so vast relative to their size. In fact, the Milky Way is right now "colliding" with several smaller galaxies and gravitationally absorbing them into itself.

We only observe this expansion of space-time with extremely distant objects (objects many billions of light years away, which we are seeing as they existed billions of years ago since their light has taken billions of years to reach us, and with which the Earth has only the most tenuous gravitational attraction), and that expansion is evidenced in the shifting of spectral absorbtion lines toward the red end of the spectrum (the rare objects moving toward us, due to factors other than space-time expansion, exhibit this shifting toward the blue end of the spectrum).

I had a character in a story once who was a college Astronomy major.

Hope the information is helpful or interesting.

 

[dr_mabeuse]

They had the expansion run backwards and found the point of origin, and as you say, where and what it started from is a mystery. Those in the know with the credentials, have supposed and theorized through probabilities, that other dimensions exist, because of the Black Holes that are present. They opine that another reality exists on the other side, because of the anti-matter, that destryos our matter. Because energy can't be destroyed, they theorize it is transformed. There's as many theories, as there are astro-physicists, but things are making more sense, because of them.

We're only aware of frequencies we can produce, or have equipment to measure, so how many more frequencies could be present? What's present in those frequencies? This is what the speculation is leading to. One thing they do know, is the expansion is speeding up.

Well, I know something about this. I worked for several years at Argonne National laboratory, right down the road from the Fermi Accelerator.

They posit that when the universe first formed, matter and anti-matter were created in equal amounts (one aspect of the Symmetry Principle). Why all the anti-matter disappeared is one of the big mysteries of cosmology. But we can create anti-matter here on earth in particle accelerators. There's nothing extra-dimensional about it.

The law of conservation of matter says that mass/energy can neither be created nor destroyed. Of course, they can be interconverted (e=mc^2), so matter falling into a black hole is converted mostly into huge amounts of energy, and the rest (as far as I know) just adds to the hole's mass. The idea that matter's shooting out into another part of the universe or into another dimension is just sci fi speculation at this point. There's no evidence for it.

Frequency is a term most commonly applied to waves, like sound (compression) waves or electromagnetic waves. Frequency is the reciprocal of wavelength, so that the higher the frequency, the shorter the wavelength It's this difference in frequency or wavelength that differentiates radio waves from visible light, or from X-ray, or gamma, or whatever.

We've examined the various frequencies of EM radiation (the electromagnetic spectrum) from the ultra-low frequency up to the ultra-high, where the wavelengths are smaller than the size of an atom (the practical limit, for quantum mechanical reasons) and we've seen no evidence of other dimensions hiding in there or anything that would indicate things are less than kosher. There are no other EM frequencies.

If other dimensions are a frequency phenomenon then it's not from EM waves. There would have to be some other, unknown kind of waves that we know nothing about and that don't interact with our universe. And if they don't interact with our universe, how are we ever going to detect them? Is it meaningful to even talk or speculate about them? We'd might as well say that extra dimensions are caused by ghosts.

 

[lance gt]

I watched a program the other night and they were talking about Quarks and the frequecies they operate on, They have noted 10 universes they operate in and how their frequencies don't correspond to normal waves, but operate harmoniously together.

I'm just a layperson who has a great interest in how it all works. The show was Steven Hawking's Grand Design and he talked of space and time and how the two operate differently from one another. One thing I don't understand, is why they think in mostly linear terms of both, that they move in one direction. Time isn't linear, it moves in at least two directions that we know of, forward and back. I noted this in the movement of waves in the water. Waves will roll in and hit a stationary object and rebound again. Instead of caneclling each other out, the rebounding waves moves through the incoming waves without impedance and continue on, until the energy of the wave is subsided. My thoughts are that time goes both ways through space, as we know it, as there is no interference of it, other than warping it.

 

[mynameisben]

I watched a program the other night and they were talking about Quarks and the frequecies they operate on, They have noted 10 universes they operate in and how their frequencies don't correspond to normal waves, but operate harmoniously together.

I'm just a layperson who has a great interest in how it all works. The show was Steven Hawking's Grand Design and he talked of space and time and how the two operate differently from one another. One thing I don't understand, is why they think in mostly linear terms of both, that they move in one direction. Time isn't linear, it moves in at least two directions that we know of, forward and back. I noted this in the movement of waves in the water. Waves will roll in and hit a stationary object and rebound again. Instead of caneclling each other out, the rebounding waves moves through the incoming waves without impedance and continue on, until the energy of the wave is subsided. My thoughts are that time goes both ways through space, as we know it, as there is no interference of it, other than warping it.

You have to realize that what gets presented on TV in a Science Show is necessarily dumbed down to appeal to a wide audience. Television producers, editors, etc. are not necessarily scientists working at the frontiers of astrophysics or quantum mechanics. Nor is it a high priority (or even an ability) of the scientific elite to take time away from their studies and research to condense decades of acquired knowledge in their field into an easily understood 5-minute blurb to a worldwide audience who will never understand a fraction of what they're saying anyway.

Quite often, what is presented on science shows as fact or theory is, in reality, merely the leading hypothesis of a leading scientist on the particular day that a microphone was shoved in front of their face. Science on the bleeding edge is in a constant state of flux, as experts grope for explanations and answers to phenomena they scarcely understand themselves. The leading hypotheses in quantum dynamics change daily, and leading scientists often proffer contradictory explanations to poorly understood phenomena. Lack of a consensus underscores how badly misused the word "theory" is. String Theory is a pop-sci and media darling, for whatever reason, but it would more properly be called the "String Hypothesis," as it does not have acceptance enough within the scientific community to be elevated to the status of a true "theory." Many of the scientific elite regard String Theory as pure baloney.

The point of all my windbaggery is this: don't take what I say or what another Lit poster says, or what you see on Nova or what Stephen Hawking writes in one of his Explaining-the-Universe books. As great an intellect as Hawking is, what he knows changes all the time. So, when it comes to sublime ideas of space and time and the nature of existence, don't feel bad if you don't get it. The reality is, with each new leap in understanding of the workings of the universe, the more we understand its complexity and how little of it we understand. The gap between discovered ignorance and understanding has been widening at an accelerating pace since day One, and the trend shows no signs of slowing anytime soon.

 

[TxRad]

What happens if you get a knot in your string theory?

Or heaven forbid, a kitten gets a hold of it?

One of the most intellectual posts I've ever seen from Ben.

Now, will the alien that swapped his brain please return the original.

 

[nicecthulhu]

OK, I'm no expert...

So if the universe is expanding in such a way, and all matter is moving away from each other, how do galaxies collide with each other? You would think that they were all ready so far apart that their individual gravities will only have a tugging effect on each other, and that collisions would be a thing of the billion years ago past. And yet it is still happening.

They are really far apart, but you have to keep in mind the time scale and the fact that the while the universal expansion may be fairly uniform on a large scale it isn't necessarily so on a small (cosmic) scale.
So, if I remember this right (it was over 25 years ago that I studied this), the theory is the big bang happens. The universe expands and the matter and energy within the universe spreads out in the expanding continuum. The analogy commonly used was an expanding loaf of raisin bread, where each raisin sees every other raisin is rushing away from it and generally the further apart two raisins are the faster they are separating.
Except, again if I remember correctly, the galaxies were starless in the beginning. These galaxies have enough time to form first and second (and third or fourth?) generation stars and black holes and other galactic doohickeys. On that massive time scale, some galaxies have time to allow a gravitational attraction draw them together into collisions.
The Big Bang Theory is the best one humans have come up with yet to describe a number of observations, but there are still big questions. Dark matter? How does something as large as a galaxy stay in one piece while being accelerated to its current velocity? How curved is space-time? Exactly how old is the universe? Is the time arrow going forwards or backwards and how do we really know if our perceptions can only see it one way? Where is momentum space? Is there sufficient mass in the universe to slow the universal expansion to a constant or will it eventually collapse? Is our current universe only one in a long chain of universes.
I seem to recall the missing anti-matter was explained as having something to do with creating an imbalance in the massive point that became the big bang. If the imbalance didn't exist then there would have been no big bang. I don't recall if that was from science or science fiction, though.
I also seem to recall that some of the great mysteries about the Big Bang Theory were explained away years ago as "if it didn't happen exactly that way we wouldn't be here to observe it". It wasn't an answer I was particularly happy with.
So many interesting things on this website...

 

[dr_mabeuse]

I'll second what Ben says, but with further remarks on just what we mean by 'understanding' or 'explaining' something. This is an argument in epistemology, which is the study what it means to 'know' something and how that knowledge is acquired.

Most scientific explanations allow us to create a mental model of some phenomenon. They allow us to understand the phenomenon in terms of what we're already familiar with. So if I tell you that atoms are like little solar systems where the electrons are planets and the sun is the nucleus, or if I tell you that gas molecules act like little tennis balls, you can 'understand' atoms or gas molecules because you relate them to known models you're already familiar with. So you're happy. They've been 'explained'.

But when you get to the edge of physics, things get too weird for models. On the very small and the very large scale, things do not act like anything we're accustomed to: particles are both there and not there. Matter becomes infinitely dense and space infinitely curved. Electrons are simultaneously waves and particles. There's simply no way to conceptualize these things into models we're familiar with.

Most of these far-out ideas come from scientists trying to figure out what a mathematical equation means. And more often than not, the scientists don't really care what it 'means' as long as the math's right. 100 years after quantum mechanics, there are still PhD's in physics who don't understand what certain aspects of quantum 'mean'. I know, because I had one of them for a teacher, and I spent years having to unlearn what he told us.

The point is, there is a limit to knowledge' as we understand it. We can't imagine the pre-Big Bang universe surrounded by absolutely nothing because we can't imagine what absolutely nothing is. When we think of nothing, we think of empty space with its 4 dimensions, which is not absolute nothingness at all.

Luckily (or by design?) our math can go where our models and imagination can't, and as far as we know the laws of mathematics apply everywhere in the universe, and can grasp a lot of things that are beyond our imagining.

J.B.S. Haldane: "The universe is not only stranger than we imagine, but stranger than we can imagine."

 

[Ruth12]

Thanks a lot

 

[lance gt]

http://news.ca.msn.com/world/eureka-physicists-celebrate-evidence-of-particle

No more theories, now they have proof.