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[Orbis Tabula]

Why would it not attract light if it does have a gravitational pull? Does it still attract other stuff, just not light?

The way Dark Matter bends light is actually key evidence that we know it's there. It's called gravitational lensing and is one of the phenomena described by general relativity. see here https://en.wikipedia.org/wiki/Dark_matter#Galaxy_clusters_and_gravitational_lensing

edit:


well, light has no mass, so it's natural to think of it as not being affected whatsoever by gravity. BUT, it turns out that the idea of a "gravitational pull" isn't so accurate. Basically, gravity is a result of distortions in space (and time, but whatever) so anything that effects can be observed by anything that travels through space (and time), such as light.

Yeah, sorry. Not trying to say that light isn't bent by it's gravitation. Just that dark matter doesn't interact with the electromagnetic radiation. It does still cause gravitational lensing. Sorry I wasn't more clear.

 

[m4st4]

I wonder if the universe gets crazier/different further out from us. Like, if it was like a layered cake, and we're in some pretty boring part of it

We're the hairy cherry on top.

 

[abstract alien]

Sounds like a microscopic version of the Bootes Void.

At nearly 330 million light-years in diameter[3] (approximately 0.27% of the diameter of the visible universe), or nearly 236,000 Mpc3 in volume, the Boötes void is one of the largest known voids in the universe, and is referred to as a supervoid.

https://en.m.wikipedia.org/wiki/Boötes_void


That's full of dark matter, right?

 

[Ether_Snake]

So is it possible that dark matter is the real "source" of gravity? As in, matter doesn't exercise a gravitational pull, dark matter does. When matter is attracted by dark matter, then naturally we get the impression that the matter is exercising a gravitational pull but it's really the dark matter that is doing so.

Dark matter would be just a lattice of sort, some parts have matter on it, some not, but in both cases it's the "dark matter" that is the only gravitational force present.

 

[SoulUnison]

I wonder if the universe gets crazier/different further out from us. Like, if it was like a layered cake, and we're in some pretty boring part of it

It gets weirder as you get closer to the center.

I'm not sure a game has ever managed to hype me up quite as much as the last hour or so of Mass Effect 2.
Real shame about the sequel, though.

 

[VaultBoy101]

It's where the upside down is located.

 

[Venture]

I've always been a bit skeptical about dark matter but this very interesting. The article doesn't go into any detail on how exactly they determined the mass of this thing.

 

[Gr1mLock]

I wanna see it. Show it to me.

 

[Woorloog]

So is it possible that dark matter is the real "source" of gravity? As in, matter doesn't exercise a gravitational pull, dark matter does. When matter is attracted by dark matter, then naturally we get the impression that the matter is exercising a gravitational pull but it's really the dark matter that is doing so.

Dark matter would be just a lattice of sort, some parts have matter on it, some not, but in both cases it's the "dark matter" that is the only gravitational force present.

What you describe sounds a bit like Higgs boson/field.
That field gives stuff mass, and mass is what causes gravity.
Dark matter happens to have mass though it isn't otherwise visible really (hence dark matter, who says scientists don't have sense of humor?). And because of dark matter's properties, it tends to clump, causing things like this newfound galaxy that has more gravity than it looks like it should have. Do note dark matter doesn't seem to be evenly distributed, so it cannot be the cause of gravity in itself.
EDIT Or something like this. I figure some astrophysicist is shaking his or her head at this, short version of how i understand this.

Funny stuff really.

I've always been a bit skeptical about dark matter but this very interesting.

Why be skeptical about it? As measured, visible matter and energy cannot account for all of the universe's mass-energy content, ergo there must be some mostly-invisible source of extra mass and energy. Mostly-invisible, because gravity lensing dark matter causes kinda reveals it.

 

[Insane Metal]

Came here to post this, haha! This is really cool news. Dark Matter is one of the greastest mysteries of our time. We need to study the shit out of this thing.

 

[Wyndstryker]

1% of the stars. Nah it's just all cloaked under the power of a super empire. It's a giant space trap.

 

[Omnii-chan]

300 million light years away

Even if we had light speed... like, fuck...

 

[Version 3.0]

There's no such thing as gravity; it's an illusion caused by mass warping spacetime. Right?

So why does Dark Matter have to have mass, causing "gravity"? It seems like a large assumption that mass is the only thing that can warp spacetime, considering.that we know nothing else about Dark Matter.

 

[Insane Metal]

There's no such thing as gravity; it's an illusion caused by mass warping spacetime. Right?

Wtf?

 

[katsubento]

So they found the source of my powers. Alright, plan b.

 

[karasu]

What ate up all the stars

Azathoth!

 

[Aikidoka]

So is it possible that dark matter is the real "source" of gravity? As in, matter doesn't exercise a gravitational pull, dark matter does. When matter is attracted by dark matter, then naturally we get the impression that the matter is exercising a gravitational pull but it's really the dark matter that is doing so.

Dark matter would be just a lattice of sort, some parts have matter on it, some not, but in both cases it's the "dark matter" that is the only gravitational force present.

No, normal matter most certainly causes gravitational phenomena.

What you describe sounds a bit like Higgs boson/field.
That field gives stuff mass, and mass is what causes gravity.

It's not really a good idea to directly tie the Higgs field with gravity/general relativity. For example, the Higgs is only responsible for at most ~1% the mass of the earth.

 

[Venture]

What you describe sounds a bit like Higgs boson/field.
That field gives stuff mass, and mass is what causes gravity.
Dark matter happens to have mass though it isn't otherwise visible really (hence dark matter, who says scientists don't have sense of humor?). And because of dark matter's properties, it tends to clump, causing things like this newfound galaxy that has more gravity than it looks like it should have. Do note dark matter doesn't seem to be evenly distributed, so it cannot be the cause of gravity in itself.

Funny stuff really.


Why be skeptical about it? As measured, visible matter and energy cannot account for all of the universe's mass-energy content, ergo there must be some mostly-invisible source of extra mass and energy. Mostly-invisible, because gravity lensing dark matter causes kinda reveals it.

No real rational reason I guess. Modified gravitational theory or our current lack of understanding of some other aspect of physics just seems more sensible to me. I've seen articles/papers about competing theories but I guess nothing explains things as well as dark matter yet.

 

[Woorloog]

There's no such thing as gravity; it's an illusion caused by mass warping spacetime. Right?

So why does Dark Matter have to have mass? It seems like a large assumption that mass is the only thing that can warp spacetime, considering.that we know nothing else about it.

Gravity-free theories are less popular than usual universe describing theories as far as i know. (EDIT Strike that, a small mix-up on my part. That's what you get when you think about physics stuff tired. Though undoubtedly someone has suggested gravity doesn't exists.) We're pretty certain gravity exists, it is after all usually classed as a fundamental force along with electromagnetism and strong and weak nuclear forces.

Mass causes gravity, which happens to warp space-time.
And mass is not the only thing that does this, energy kinda does so too (mass and energy are the same thing after all, per E=Mc^2). Dark energy for example, which seems to affect universe's expansion; i'd say that's pretty clear example of energy warping space.

Dark matter must have mass because it causes gravity lensing. As to why it has mass... it does. It is stuff that has mass but not much else, and no one has any real idea what it is.

It's not really a good idea to directly tie the Higgs field with gravity/general relativity. For example, the Higgs is only responsible for at most ~1% the mass of the earth.

Well, whatever explanation i've seen has been pretty wrong then. Or i understood it wrong. Or both.

Does Higgs cause mass only for certain things then?

 

[lastplayed]

Do we know what Dark Matter does exactly? Does it block light, can be used for fuel, what exactly?

Doesn't block light, as others have said, it's just invisible to all forms of detection, except gravity.

There's probably dark matter right in front of your eyes now.

 

[Lijik]

Ah, dark matter. Good thing I'm a platforming expert!

With your username i wouldve expected

 

[Air]

Keanureeveswhoa.gif

 

[cdyhybrid]

 

[Walter White Walker]

What percentage of the Milky Way is dark matter?

The universe is roughly 68% dark energy, 27% dark matter, and "normal stuff" (stars, planets, etc.) makes up less than 5% of it.

http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/

 

[foxuzamaki]

Can't wait to see what kind of fictional stories we get with this knowledge, tho it might just be the anti spiral story ad nauseum

 

[low-G]

Or a galaxy completely farmed of it's resources littered with the dormant mechanical purge-suits of its hibernating super-intelligent masters just waiting to be discovered...

Or they are cloaking / dimming their galaxy to blend in to the surrounding noise... Then again that's the first thing you'd look for if you were supreme overlord of the universe...

 

[HStallion]

So this means the Galaxy is total horse shit in the end?

 

[WillyFive]

What percentage of the Milky Way is dark matter?

Some estimates have it at 5 to 1 dark matter to normal matter, however you could also imagine it as water on a beach; the foam is normal matter, and the rest of the water is dark matter.

 

[Log4Girlz]

This news is falling in nicely with a possible new force of nature. They have detected what could be a new force and they believe it allows dark matter to interact with normal matter in a very, very, very weak manner. Like, unbelievably weak.


SCIIIIIENCE

 

[Aikidoka]

Well, whatever explanation i've seen has been pretty wrong then. Or i understood it wrong. Or both.

Does Higgs cause mass only for certain things then?

The Higgs field results in the masses of the electron, quarks, and other fundamental particles (namely muon, tau, W+'W-, and Z). Now, if you consider the proton, it is a very complicated object that does indeed get some of its mass from the fundamental quarks that make it up. However, the vast majority of the mass comes the energy due to the strong and electromagnetic interactions that bind the proton together. Simply put, the internal energy of an object can translate into seeing a different mass than what you'd expect from just adding up the masses of each fundamental particle inside the object.

 

[GAFmeansLIFE]

Populated entirely by:

 

[Armaros]

It doesn't block light, it just doesn't interact with it at all. That's why they call it dark. You can't find it by looking at how it reflects or refracts or absorbs light, because it doesn't do anything. We do know that it has mass, because it does exert a gravitational effect. That's the only way we can see it: By noticing that some large invisible gravitational force is doing something to its neighbors. For example, galaxies spin at a rate that doesn't make sense if you only add up the visible mass, so there must be invisible mass to explain how galaxies aren't constantly being flung apart by their own rotation.

And many galaxies literally couldn't exist without dark matter because when people did the math, the galaxy didnt have enough visible matter to have enough gravity to keep it all together.

Similar to the dark matter galaxy they discovered but on a lesser scale.

 

[Air]

This news is falling in nicely with a possible new force of nature. They have detected what could be a new force and they believe it allows dark matter to interact with normal matter in a very, very, very weak manner. Like, unbelievably weak.


SCIIIIIENCE

I saw that on Reddit but wasnt that dismissed? I thought I read something about those scientists being shady. Could be wrong though (and honestly I'd like to be, a new force of nature would be cool to learn about).

 

[Woorloog]

The Higgs field results in the masses of the electron, quarks, and other fundamental particles (namely muon, tau, W+'W-, and Z). Now, if you consider the proton, it is a very complicated object that does indeed get some of its mass from the fundamental quarks that make it up. However, the vast majority of the mass comes the energy due to the strong and electromagnetic interactions that bind the proton together. Simply put, the internal energy of an object can translate into seeing a different mass than what you'd expect from just adding up the masses of each fundamental particle inside the object.

So... Higgs accounts for mass of "physical" (for lack of a better word) part of particles but that's minor amount overall?

 

[Aaron Strife]

You can just steal some from the last boss in Final Fantasy IV.

 

[Clydefrog]

Dark matters matter

 

[Log4Girlz]

I saw that on Reddit but wasnt that dismissed? I thought I read something about those scientists being shady. Could be wrong though (and honestly I'd like to be, a new force of nature would be cool to learn about).

http://phys.org/news/2016-08-physicists-discovery-nature.html

Seems legit to me. I'm no expert tho

 

[The Technomancer]

So... Higgs accounts for mass of "physical" (for lack of a better word) part of particles but that's minor amount overall?

Sorta. Mass is a devilish thing to try and describe. It's a thing that gravity is proportional to. It's a thing that inertia is proportional to. That's really it. There's no "physical" mass, just different ways "things" can have those properties

 

[AxelFoley]

There are more things in Heaven and Earth, Horatio...

 

[Polioliolio]

300M light years away. Jesus Crisis.

I wish I could truly grasp this, but anything more than like 50 miles and it's just a big number.

300 million.. 300 million years to travel that distance if going the speed of light. For an object to travel at possible speeds, it would probably take the entire age of the universe as it is now, to get that far.

So much cold empty space. Amazing. I hope I love long enough to hear all kinds if cool shit about space and science... Freeze me and wake me up 1000 years from now.

 

[Version 3.0]

Dark matter must have mass because it causes gravity lensing. As to why it has mass... it does. It is stuff that has mass but not much else, and no one has any real idea what it is.

But that's my point: this is assumption. We know that mass (or gravity, if you insist, but my understanding is that Einstein said no; it was the cornerstone of his thinking for general relativity - no force could be instantaneous, as gravity was thought to be) warps spacetime. Mass (or gravity) is not directly causing gravitational lensing; the light is merely following the curve of spacetime.

So we can see that spacetime is curved, and we assume that curvature is caused by mass, because mass is the only thing we know of that does so. But why is that considered a safe assumption in the absence of all other information? "We know it has mass but nothing else", you say. I say no, we know spacetime is curved by the same amount X amount of mass would curve it, and that's all.

Spacetime curvature is often visualized with a sheet of fabric, with weights placed on it. What I'm saying is this: it's as if we said "only by placing weights can this sheet be curved". Then we see it's curved in a spot with no weight, and we say "there's an invisible weight placed there, because that's the only thing that can curve the sheet". What I'm saying is...what if the sheet's being pulled down from the other side? It's not a safe assumption that it's a weight. We don't know.

But I digress. The answer, as much as there is one, and even the actual question would be properly expressed in math that's beyond my comprehension.

 

[Air]

http://phys.org/news/2016-08-physicists-discovery-nature.html

Seems legit to me. I'm no expert tho

Thanks for the link. Crazy if true. If they open this can of worms im sure it's gonna get a ton of attention, so I would imagine if it's legit we'll be hearing more about it from other groups.

 

[opticalmace]

I'm getting Dark Souls vibes.

 

[Log4Girlz]

But that's my point: this is assumption. We know that mass (or gravity, if you insist, but my understanding is that Einstein said no; it was the cornerstone of his thinking for general relativity - no force could be instantaneous, as gravity was thought to be) warps spacetime. Mass (or gravity) is not directly causing gravitational lensing; the light is merely following the curve of spacetime.

So we can see that spacetime is curved, and we assume that curvature is caused by mass, because mass is the only thing we know of that does so. But why is that considered a safe assumption in the absence of all other information? "We know it has mass but nothing else", you say. I say no, we know spacetime is curved by the same amount X amount of mass would curve it, and that's all.

Spacetime curvature is often visualized with a sheet of fabric, with weights placed on it. What I'm saying is this: it's as if we said "only by placing weights can this sheet be curved". Then we see it's curved in a spot with no weight, and we say "there's an invisible weight placed there, because that's the only thing that can curve the sheet". What I'm saying is...what if the sheet's being pulled down from the other side? It's not a safe assumption that it's a weight. We don't know.

But I digress. The answer, as much as there is one, and even the actual question would be properly expressed in math that's beyond my comprehension.

The only thing known to bend spacetime is mass/energy. Any other claim is baseless.

 

[The Technomancer]

The only thing known to bend spacetime is mass/energy. Any other claim is baseless.

Right. There could be some mechanism imparting mass into a form of matter we don't understand yet, but by semantic definition if it bends spacetime it possesses mass.

 

[DiipuSurotu]

Sounds like a microscopic version of the Booted Void.



https://en.m.wikipedia.org/wiki/Boötes_void


That's full of dark matter, right?

 

[Version 3.0]

The only thing known to bend spacetime is mass/energy. Any other claim is baseless.

Exactly my point! "The only thing known". But we're discussing something that is unknown, not something that is known. There is something unknown bending spacetime. Look back through history. How many times was something "the only thing known" and yet is not today?

Have you ever seen Neil deGrasse Tyson talk about UFO believers? He mocks them by 'quoting' them like so: "I don't know what it is...it MUST BE aliens" and says that sentence should end before the assumption. Here's a link:

https://www.youtube.com/watch?v=Ugten5d1HTU

Similar scenario: Something is bending spacetime that we can't (otherwise) detect. We don't know what it is...it MUST BE a new kind of invisible matter.

Except that I don't think that's what happened. I'm asking. I'm not naive enough to think I'm the only person who ever thought to question this. But I've seen very little about any competing, but dismissed, hypotheses. So I wonder, what was the process, or evidence, by which other possibilities were ruled out, or at least deemed less likely, since dark matter is obviously the leading hypothesis. I seriously doubt that mechanism was "it is known".

 

[Dreams-Visions]

super fascinating

 

[sono]

What if something lives there, something that we aren't meant to disturb

Like SMAUG

 

[Erevador]

Another fascinating discovery. Exciting to live in an age where we learn more and more about the universe with each passing day.