Milky Way Is Being Pushed Across the Universe (cnn.com) 149
dryriver quotes a report from CNN: Our home galaxy, the Milky Way, is being pushed across the universe by a large unseen force, according to new research. Although it may not seem like a friendly gesture, the newly discovered Dipole Repeller is actually helping our galaxy on its journey across the expanding universe. Researchers have known that the galaxy was moving at a relative speed for the past 30 years, but they didn't know why. "Now we find an emptiness in exactly the opposite direction, which provides a 'push' in the sense of a lack of pull," said Brent Tully, one of the study authors and an astronomer at the Institute for Astronomy in Honolulu. "In a tug-of-war, if there are more people at one end, then the flow will be toward them and away from the weaker side." But this is no aimless journey of motion. Researchers have long believed that our galaxy was attracted to an area rich with dozens of clusters of galaxies 750 million light-years away, called the Shapley Concentration or Shapley Attractor. "We found a flow pattern reminiscent of streams of water that are organized by gravity to run downhill," Tully said. "In detail, we played a mathematical trick by inverting the sense of gravity to see where flows would terminate in this altered case. Flows ended at our Dipole Repeller."
Beware the Cosmic Drain! (Score:1)
Re:Beware the Cosmic Drain! (Score:5, Informative)
"Now we find an emptiness in exactly the opposite direction, which provides a 'push' in the sense of a lack of pull," said Brent Tully, one of the study authors and an astronomer at the Institute for Astronomy in Honolulu. "In a tug-of-war, if there are more people at one end, then the flow will be toward them and away from the weaker side."
But ... that doesn't mean the weaker team is 'pushing', does it?
(facepalm)
Re: (Score:2)
If you find yourself moving, look ahead and then look behind. If it is a push, there will be more stuff behind us. if it is a pull, there will be more stuff in front of us. This is important because it is unlikely that any attractive forces are fundamental, which means all apparent attraction is simply a side-effect of repulsion. This discovery adds to the body of evidence supporting that idea. The next challenge is, we need to prove that gravity is not an attractive force but the side-effect of a more fun
Re: (Score:2)
Haven't scientists the world over have known since Sir Isaac Newton that gravity is a one way force? Does this guy even know what he is talking about?
There is no push and pull of gravity.
or possibility B. We've learned something new in the last 300 years.
Re: (Score:1)
The push is created by differential attraction. The repeller is an area empty of matter which means that there is less gravitational pull from that area, the net result is a push..
It is very debateable whether true negative gravity exists, however all it requires is a negative curvature of space / space time so is theoretically possible.. Negative gravity could exist in certain conditions inside wormholes - or as the theoretical 'white' holes.
But we're flush with success! (Score:2)
I have not received any such information from either the elephants or the turtle. Therefore, I doubt the veracity of this.
However, should it prove to be true, I suggest we destroy all the observatories so this can never happen again.
Re: (Score:2)
It doesn't matter either way. It wouldn't change our reality.
How would you know?
Re: (Score:2)
There's a PARTY over there! Let's Go!
"Helping our galaxy on its journey" (Score:2)
What does this even mean in a non-teleological universe?
Wait, what does this even mean even in a teleological universe?
Re:"Helping our galaxy on its journey" (Score:5, Informative)
What does this even mean in a non-teleological universe?
"We're moving in the direction gravity is pulling us."
Re:"Helping our galaxy on its journey" (Score:4, Informative)
Mod +1. This is the second or third time I've seen summaries of the press announcement, and the first time it has been even obliquely acknowledged that the so called "repeller" is nothing more than a localized lack of PULL, not any sort of actual gravitational "push". -1 to the article itself for being misleading bullshit and creating a "dipole" like an electron and an electron hole create a "dipole" in a uniform neutral metal, no more.
Surely there is nothing surprising about this. People have been doing cosmological simulations for a LONG time with a large number of pointlike objects interacting with GMm/r^2 attractive forces but to simulate galactic evolution and universal evolution from the big bang. The interesting point being that in the center of a uniform mass distribution, there is no net force but nevertheless 1/r^2 forces with any kind of inhomogeneity in the underlying free mass distribution tends to accrete in some places and abandon others, especially if it can inelastically interact and clump together into bound subsystems. This must have been seen in simulations pretty much every time, and should come as no surprise in nature.
Re:"Helping our galaxy on its journey" (Score:4, Interesting)
The approach being used that identifies the repulsor is a valid one. Bicycle mechanics have been using it since at least 1890 in practical work.
When truing a bicycle wheel, it makes sense to talk about the push that a spoke exerts against the ground that keeps the wheel from collapsing. While you cannot push a string, the tensile pulling forces of all the spokes toward the top of the wheel are too complex to easily analyze. But fortunately it works out that you can invert your frame of reference and then not worry about those forces since in the inverted framework those tensile pulling forces become a single push through the one spoke that opposes the sum of the vectors of all the other spokes.
A miniaturized bicycle mechanic standing on the inside surface of a wheel's rim could use this pushing vector to figure out where the hub of the wheel was. That is never done only because bicycle mechanics are big enough to eyeball the entire wheel. But scale the metaphor up....
That is what is being done here. It is an interesting study, and much more than a theoretical sleight of hand. It suggests that the Milky Way is moving away from a specific point, which they are calling the "Dipole Repulsor", but which can also be described as the Center Of The Big Empty. I did not see anything in the article that suggests that we know how far away the COTBE is, but it looks like we at least know its direction from Earth, the Solar System, and the Milky Way. That's more than we knew before.
It has long been understood that the universe is expanding like the surface of a balloon that is being inflated. This work suggests that we may now know the direction to the center of the (possibly local) universe. I'm not entirely sure of the scale of the implications... this could be on the scale of the Copernican Revolution.
Re: (Score:2)
I think "center of the local universe" is going a bit far. To use a metaphor I used in another post further down, it's more like they've found the top of the nearest "hilltop" in the "rolling hilly countryside" that is the curvature of spacetime. The Shapley Attractor would similarly be the bottom of the nearest "valley". Both "hilltop" and "valley" in the sense that if you trace the lines that "water would flow" (to use the bit of good analogy the article does employ), they converge in a place downhill (th
Re: (Score:2)
Your hills and valleys analogy has stronger legs than my bicycle analogy. I'll go with it. Thank you.
Re: (Score:2)
Thank you. I did appreciate your bicycle analogy too, and didn't mean to put it down at all, just the "center of the universe" bit.
Re: (Score:2)
Now it could be that mostly empty space expands faster than this or maybe there is some other thing that happens in mostly empty space. The point is that we see matter moving away from the "repeller" and it maps more closely to how you would see particles moving between poles of a magnet than just being attracted by one object.
Re: (Score:2)
Wait, what does this even mean even in a teleological universe?
Milky Way got places to be, it ain't got no time for that.
Re: (Score:2)
Stop anthropomorphizing the Milky Way. She doesn't like that.
Re: (Score:2)
That almost leads into a "your momma so fat" joke...
Re: (Score:2)
Hm (Score:5, Interesting)
If I understood this right they are calling the lack of attraction, repulsion. There's no negative force, or dark energy style shit involved. Shouldn't they call it a non-attractor unless they show active repulsion? If I drop an object and it moves towards the ground I am not going to say my hand repelled it.
Re:Hm (Score:5, Informative)
If I understood this right they are calling the lack of attraction, repulsion.
Yes, you understood it right. They also provide the analogy of a tug-o-war rope being "repulsed" by the end with fewer people tugging on it. That is the stupidest analogy I have heard all day. The rope, of course, is not being "pushed" and neither is the galaxy.
Re: (Score:3)
Re:Blackholes don't have strong gravity (Score:4, Insightful)
Right! And what we call light bulbs are actually dark suckers.
You can joke if you wish, but in physics you may have heard of something called a "frame of reference," which specifies the default state you assume. That's not quite analogous to what TFA is doing, but it's something like that.
Newtonian physics assumes a default frame of reference that has no forces in it. Hence, we only talk about forces "existing" when they are non-zero.
But this "no forces" frame of reference doesn't really make sense when talking about the universe on large scales. Instead, the default state of the universe is a general curvature of space-time that galaxies exist within. You could perhaps think of it has a general "slope" on the rubber sheet model of spacetime. Or, if you insist on the tug-of-war analogy, the "default" state is with a certain level of tension. If you grew up as part of a "rope" within a universe like that, you'd probably develop a system of physics where the default "frame of reference" included tension forces pulling at you on both sides.
Anyhow, the "push" and "pull" and gravity doesn't quite make sense in terms of our normal analogy of grabbing onto something and physically pushing or pulling it. Rather, thinking of spacetime as curved, we change the slope. In the case of TFA, we have the default "slope" that pervades the universe, and previous research says our galaxy is moving in direction X more than the slope would suggest due to increased curvature in that direction. But it turns out there's also decreased curvature in another direction, which effectively decreases the threshold of the "default slope" in that direction.
If you lived as a "rope" in a continuous tug-of-war game since the beginning of time, which mostly had a default "tension" pulling at you from all sides... then you'd likely perceive a decreased tension as a "push" too. Since the whole "push/pull" thing is a bad analogy for gravitational spacetime curvature on a cosmic scale anyway, I'm not sure why everyone here is making fun of a bad analogy while upholding their bad analogy. They're both seriously flawed in this case.
Re: (Score:2)
In some cases, you can reformulate the math in a model so it's easier to work with at the cost of becoming non-intuitive. I don't know if this is one of those cases, but it's possible that treating empty space as a repulsor made it easier to calculate something.
Re: (Score:2)
Re: (Score:2)
Someone correct me if I'm wrong, but the idea of a "repulsive force" makes some sense here if you are viewing things in relationship to the overall pattern of universe expansion and motion.
That is, we know the Milky Way is moving at some velocity in relationship to the cosmic background radiation. If the cosmic background radiation can be thought of as the "stable earth" or whatever as a frame of reference, our galaxy is moving in relationship to it.
If I understand this study correctly, it's been previ
Re: (Score:2)
They also provide the analogy of a tug-o-war rope being "repulsed" by the end with fewer people tugging on it. That is the stupidest analogy I have heard all day. The rope, of course, is not being "pushed" and neither is the galaxy.
This explains why Physicists never win in the interdepartmental tog-o-war contests.
Re: (Score:1)
It is real repulsion, only it is differential repulsion rather than direct repulsion.
Re: (Score:2)
The ludicrousness of this becomes even more apparent when you think of actually pushing a rope.
Indeed, "pushing rope" is slang for trying to have sex with half a hard on.
Re: (Score:2)
It's really very simple: The Earth which could be above the object but isn't is pushing the object toward the Earth which could be below the object and is. You are a slow learner, Winston.
Re:Hm (Score:5, Informative)
If I understood this right they are calling the lack of attraction, repulsion. There's no negative force, or dark energy style shit involved. Shouldn't they call it a non-attractor unless they show active repulsion? If I drop an object and it moves towards the ground I am not going to say my hand repelled it.
That is the wonderful thing about maths. Math can be both fun and insightful for a great number of things beyond simply 'describing reality'.
You may say "This has 60% of some quantity" but that doesn't mean it in'ts equally true to say "This lacks 40% of some quantity" simply because you don't wish to describe it that way.
So long as the percentages add up to 100, both statements are true.
You are also making two very big mistakes in your assumptions, one of which I am going to fault you for.
One, math does not need to be restricted to describing reality.
You remind me of people that say "Computers should only exist to do X, and you are *wrong* for making software for any other purpose"
Two of course is - stop putting words in other peoples mouths! And shame on you for doing so!
These people never once claimed their math represents reality, and never claimed there is any such thing as a force of repulsion being proved here. You quite literally made that up and attributed that factually wrong statement as something they claimed.
In this case they are using the math as a little game. Reverse your point of view and focus on the other side of the equation just purely to see what happens.
After they did so, they were able to show not where gravity is pulling things, but where those things were prior to being pulled, thus showing more detail on the path they have traveled.
The really interesting thing that came out of this is when they pretended the math was correct and actually looked through a telescope to the place in space indicated as the start of the trip for our galaxy.
They noticed that, in reality, more galaxies than just ours are moving away from this point.
This provides insight that wasn't thought to be looked for previously.
Not only are there large clumps of mass gravitational pulling things to them, but there are also large areas with little to no mass they are being pulled away from.
It has always been thought that galaxies are 'born' in high mass galactic clusters and flung out by forces such as super novas and such.
We now have observational evidence this isn't always the case, which we did not have before.
Being just a starting point for what to observe, clearly there are few if any conclusions beyond that we can draw from this, but we now have a better idea of places to look that very well may be more interesting than previously assumed.
Maybe after checking the observations nothing comes of this, and this was just some strange coincidental anomaly that came out of the math for these two runs of numbers.
Maybe it will turn out this will be a useful method to trace back the path of galaxies in more detail than we had before.
But when you have trillions upon trillions of things in space to pick to look at, anything that can raise something to a higher priority instead of simply choosing at random is worth while.
And whatever criteria you used to choose does not need to be some mathematical proof of a deeper explanation of reality, it's only requirement is pointing us in a direction to look that has some, any, amount of meaning behind it above just rolling the dice.
An implicit claim of repulsion (Score:2)
These people never once claimed their math represents reality, and never claimed there is any such thing as a force of repulsion being proved here.
To be fair, they named this thing that isn't doing any repelling the "Dipole Repeller." That's an implicit claim of repulsion.
Re: (Score:1)
Differential repulsion.
Re: (Score:2)
Well, you see, the other comments around it sucked, because they were stupid, so if we reverse the math we can describe stupid posts as the norm and ones that lack stupidity as expanding or something.
Re:Hm (Score:5, Informative)
Attractor [wikipedia.org] and repeller are, in this case, being used as very technical terms to describe the behavior of those regions of space in the velocity field of the universe. Neither the repeller nor attractor needs to actually be exerting any physical force at all.
Re: (Score:3)
I think the (mildly) interesting thing here is hidden behind all the bad analogies, but they actually do mention a tiny bit of a good analogy.
Say you're a ball on a hill in a rolling hilly countryside, and so under gravity you're rolling downhill. You can easily calculate where you will eventually settle, when you reach some local elevation minimum too deep for your kinetic energy to escape you from. You can find those minima by "seeing where water would flow", which is the tiny bit of good analogy they tou
Re: (Score:2)
If I understood this right they are calling the lack of attraction, repulsion. There's no negative force, or dark energy style shit involved. Shouldn't they call it a non-attractor unless they show active repulsion?
Despite what some of the other answers have ranted in agreement, this is a not-uncommon phraseology in science and engineering. Maybe a few of you have heard of holes propagating in a semiconductor, for example. Try not to get all wound up about a simple way to describe system behavior using simple analogies.
Re: (Score:2)
They are not calling a lack of attraction a repulsion. They are specifically showing that this is not the case. They have mapped the velocities of objects and objects are moving from the Dipole Repeller to the Shapley Attractor but the velocities indicate that gravitational pull is not the only force in play. There might not be a force pushing objects away from the Dipole Repeller but objects are acting like they are being repelled. i.e. they are
Re: (Score:1)
It does seem like they are calling a lack of stuff in one direction a pushing or repelling force. By that thinking, our sky is a "pushing force" also because there is very little stuff there (nearby) compared to the ground (Earth).
"Dark Nothing"?
Dark matter, dark energy, dark gravity, I suspect there is dark bullshit going on; the Aether(s) of our time. Now they are using it for nothingness too.
Dark Fad.
It's all relative (Score:1)
"Researchers have known that the galaxy was moving at a relative speed"
Relative to *what* though?
Re: (Score:2)
Relative, as in "non-absolute" :)
Re: It's all relative (Score:3, Informative)
Still lacking an answer... (Score:1)
Re: (Score:3)
if there were, it should have been called "Shapely Attractor".
Re: (Score:3)
Oh please, that's just marketing. Remember "Greenland"?
Re: (Score:2)
Oh please, that's just marketing. Remember "Greenland"?
Yes. Tends to make you wonder if this is the true origin of all bullshit in marketing, given that "Iceland" exists...
Re: (Score:2)
And as soon as you have any kind of indication for this to possibly hold some water, we might even discuss it.
That's the point about science. Yes, we can all come up with all sorts of wacky ideas, don't worry, but in the end, what counts is to be able to at least show that it could be true.
What you're doing here is the equivalent of speculating what was before the Big Bang. There is no way whatsoever to even possibly begin to falsify your claim. And claims that cannot be tested are worthless from a scientif
Re: (Score:2)
Very true, but intuitively I know that the 'Big Bang' started with a box of spaghetti and some boiling water.
Re: (Score:2)
"... distances of ~20,000kms1 or more" ??? (Score:3)
Re: "... distances of ~20,000kms1 or more" ??? (Score:1)
It is definitly wrong to say it like that.
But, with some context it could be acceptable.
If you show a clear relation between distance and speed then you could refere as a distance where speed is X.
But becouse they are talking about 10^3 on onside and 10^5 on the other, i think it is a simple mistake in units.
Re: "... distances of ~20,000kms1 or more" ??? (Score:1)
Re: (Score:2)
Re:"... distances of ~20,000kms1 or more" ??? (Score:5, Informative)
This is what I read from the original article. To my very limited ability to understand, it seems that "Km s-1" is a speed, not a distance.
You may want to read up on the Hubble constant [wikipedia.org]. When talking about large distances in the universe, there is no direct way to measure them. Instead, we measure red shift. Red shift is used to calculate velocity. Velocity is used to calculate distance. There are various assumptions at each stage of calculations.
And then there are other complexities about what you actually mean by "distance." Astronomers have various ways to calculate it, but it's complicated by relativistic effects, not to mention the problem of how to talk about distance in relationship to things where you only know where they were by light that left millions or billions of years ago. So, are you talking about distance "then" or "now" or something else? And there's the fact that space is actually expanding over time, so are you talking about "proper" distance or comoving distance [wikipedia.org]. And your calculated "distance" could depend on the exact cosmological model you're using and assumptions about the future development of the universe.
To avoid some of those complications, it's more accurate to report the actual measurement you're taking when talking about "distance," which is redshift. Or you could go one step further and calculate the Hubble velocity based on the redshift, while ignoring the complications of "distance" mentioned above. That's what is being done here -- and it's quite common in astronomical literature. If you had bothered to read to the end of the second paragraph, you'll discover they actually explain this: "The Cosmicflows-2 dataset of galaxy distances provides reasonably dense coverage to R ~= 10,000 km s-1 (distances are expressed in terms of their equivalent Hubble velocity)."
I agree with you that it would probably have been clearer to people unfamiliar with this usage to put that explanation after the very first use of the Hubble velocity as distance... I assume they probably just didn't want to do that because stylistically it clutters the very first sentence of their article.
Re: (Score:2)
Re: (Score:2)
The problem is still the same: don't change the name of the things and don't assign new and different meanings to names!
If it's a speed, then it can be m*s-1, if it's a distance, then it's m.
If you need a different concept, then use its name and its definition.
A distance is a distance is a distance is a distance!
Isn't this a kind of proof that gravity is push? (Score:4, Interesting)
I think space itself is some kind of medium and not necessarily matter based. Currently, its composition is unknown. You can call this medium aether if you like, just do not confuse it with the luminiferous aether. There are several aether theories out there, one of the popular ones is the Superfluid Vacuum Theory.
Now, back to gravity. We know since Einstein that matter curves/disturbs space**. So, this medium, which is disturbed by matter, wants to be 'smooth' and it exerts a force on matter. This force is obviously a push force and we call it gravity.
From our perspective there is no way to differentiate between pull or push. Maybe until now.
** I know that according to GR gravity is a curvature of space-time and not just space. But if space itself is some kind of medium then the time dimension simply does not exist. What happens is that the disturbance of space prevents matter particles to interact with each other. We perceive this lack of interaction as if 'time' slow down since there is no change (We can only perceive 'time' by observing change). This picture is compatible with GR since relativity between moving bodies through space remains. However, it establishes a distinguished reference frame which is space itself.
Re: (Score:2)
Re: (Score:3)
Re: (Score:2)
Re: (Score:2)
I think space itself is some kind of medium and not necessarily matter based. Currently, its composition is unknown. You can call this medium aether if you like, just do not confuse it with the luminiferous aether. There are several aether theories out there, one of the popular ones is the Superfluid Vacuum Theory.
I guess its really true that everything old is new again [wikipedia.org]
Re: (Score:2)
What about those fat bottom cursive two's. Adding two of them together could be closer to 5 than the sum of a pair of little skinny two's.
Re: (Score:2)
What about those fat bottom cursive two's. Adding two of them together could be closer to 5 than the sum of a pair of little skinny two's.
That's what happens when you Round your numbers.
It's the most powerful force in the universe... (Score:5, Funny)
Re:It's the most powerful force in the universe... (Score:5, Funny)
You know why Hurricanes are named after women? When they arrive they are all wet and wild and when they leave they take your house, your card and everything else.
So much for your theory then.
Re: (Score:1)
Yea, it is the only force in the world that men spend billions upon billions of dollars on to obtain and never ever get.
Pesky titans! (Score:2)
I know I shouldn't care. Us mortals will not live to find out what happened...not even our children's children...but it's the principle damn it.
Stop playing tug-of-war with my galaxy! if you're not careful you'll push/pull/repulse/attract it off the side of the universe!
CNN fake news (Score:2)
They are not that bad. (Score:4, Funny)
If humans want to build a highway, they just build it and don't bother too much about the disruptions and dislocations caused. Despite what you might have heard about them sneakily filing a redevelopment plan and filing it in a dark basement guarded by leopards, in reality they move the entire galaxy away before embarking on such a project. We are just beginning to understand them.
Across the Universe (Score:2)
In other shocking news: Stars shine! (Score:2)
The Dipole Repellers (Score:3)
We are still going to crash into Andromeda (Score:2)
wtf ? (Score:1)
And I feel myself being pushed thru my chair by a strange force located someplace above my head ... wtf is this strange repulsive force ?
Geebus !
Re: (Score:2)
It's actually this electromagnetic repulsive force that keeps pushing you out of your proper worldline, meaning the one you'd follow through spacetime if there was no outside force (if you were in free fall). This is caused by the distortion of spacetime that makes worldlines tend to go near the center of the mass, and the fact that the mass repels itself electromagnetically at close range.
re: Milky Way Is Being Pushed Across the Universe (Score:2)
This HAS to be the best thing ever - all I will have to do is make sure there is nobody behind me and I can get my car to propel itself forward with NO FUEL EXPENDITURE - - - better than any application of 'flux capacitors'.
Just imagine, with nothing behind you, your mileage will go off the chart, since it won't require any fuel or engine usage to get you moving into the vast frontiers of ANY spatial locale, and all without ANY requirement for fuel ! ! !
Hell of a revolution in the physics arena, since you c
"The Shapely" attractor....Daisy, my 2nd wife (Score:1)
Ummm, coffee, anyone?! (Score:1)
This provides a 'boost' where there is a lack of 'sedating matter'!
Re: Exactly how does this affect my life? (Score:1)
You've stumbled onto the wrong site, this is the site you are looking for: https://www.reddit.com
Re: (Score:2)
You shouldn't invest in that real estate in Georgia, for Georgia is where we'll collide with Planet IX-533 in roughly 55.2 billion years.
Re: (Score:2)
Do you mean Georgia the American state, or do you mean Georgia the country?
Or Georgia, the chubby girl I went to school with?
Re: (Score:1)
Do you mean Georgia the American state, or do you mean Georgia the country?
Or Georgia, the chubby girl I went to school with?
It's all the same, ending with you crying, holding a tube sock and a tub of vaseline while browsing pr0nhub on a Friday night.
Re: (Score:3, Funny)
Re: (Score:2)
Do you expect the rest of us to give a shit about whether you give a shit? Because I don't.
As one of New Scientists' most successful editors once said "Science is interesting, and if you don't agree you can fuck off."
So go ahead, fuck off.
Re: (Score:2)
"I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today."
So, only really expensive designer brainburning drugs for you, eh? Or is it cheap brain enhancing drugs (he says, sipping his coffee...:-)
rgb
Re: (Score:2)
Re: (Score:1)
Causing (Score:1)
Re: (Score:2)
Midi chlorians.
Re: cause by (Score:2)
I'm not saying it's aliens, but... it's aliens.