The Dark Matter Mystery: Gravitational Lensing

A mystery exists! Galaxies do not seem to have enough mass for stars to orbit at their observed speeds. Galaxies should be flying apart, but they don't. Why not? Explore the surreal world of dark matter - one of the universe's greatest mysteries.

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This presentation is available to educators on DVD and comes complete with specially-crafted teacher notes.

The Mystery of Dark Matter Video Game

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A gravitational lens is formed when the light from a very distant, bright source (such as a quasar) is "bent" around a massive object (such as a cluster of galaxies) between the source object and the observer.

The process is known as gravitational lensing, and is one of the predictions of Albert Einstein's general theory of relativity.

The gravity from a massive object (such as a galaxy cluster or black hole) is warped space-time, bending everything in it—including the paths followed by light rays from a bright background source.

This alters the time taken for the light to reach an observer, and can both magnify and distort the apparent image of the background source.

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[TheUndertker]

Wow, the depth of detail in the universe is ridiculously amazing. We're still ignorant savages.

[Exilea]

Good sceptics looking in both directions THAT's Sience :D

[GrindInYOURcore]

Did everyone listen to what they had to say.. "Mysterious force"..."Something out there we can see".."We dont understand how things are working"..."Evidence always points to say place"..  "Maybe we got the picture completely wrong and we should be open minded"...  When you force the wrong puzzle pieces together the big picture is always wrong... Their model is leaving out the most fundamental pieces of the puzzle.. God...  Whats your interpretation of the presupposition assumption of  speculative presumable evidence??? 

[Jiggerj]

Why isn't Dark Matter and Dark Energy just considered a force? If they have no particles that can be detected why are scientists looking for a physical thing?

[JSprayaEntertainment]

WRONG ....
watch ( Primer Fields Theory )
Watch ( Electric Sun ) Stuff to understand things like plasmoids ...
there is a lot you would need to learn to understand gravity better, but we are far past dark matter in 2014 ... ( this was an ok upload for 2010 thou ) things are moving fast thou

[Levon]

@gogogeedus I agree with you we are not part of animal kingdom, but we use to be. The only reason we became to be who we are because ones in the life time our far ancestors couple million years back they were under achievers. We are like vessel for our cells because of them human brain grew larger past ancestors learn how to hunt food not to become food for other animals. And that progress went on up to date.

[Levon]

@gogogeedus I like the way you express your self about current scientists work it seems to me they more of dream chasers than realistic about true existence of universe. I'm amateur scientist it took me 32 years to comprehend how function our universe. I use simple physics & simple algebra to comprehend how things are functioning. I will tell you with confidence there is no anti matter or dark matter & light never bends. Things aren't that complicated the way scientists see it.

[Eugensdiet]

Thanks Shelly but I think your oversimplifying things. You can't use the center of the galaxy as the center of mass when using a star to determine the mass of the galaxy ( to much of the mass is distributed thru the galaxy) especially when you have already stated (not you) that the motion of the stars are not behaving the way they should. I know that was a little repetitious but I don't think you understood what I said the first time. One cosmologist questions its existence another makes a map?

[Eugensdiet]

In an earlier video it was explained that the stars in a galaxy maintain similar velocities going from inside out. That is not consistent with Newton's laws. It was then explained that this was caused by dark matter. He also calculated the mass of the galaxy erroneously. He makes two mistakes. He picks a star that he knows isn't behaving correctly and uses it's velocity to determine the mass of the galaxy. He treats the mass of the galaxy as a single point at it's center. That doesn't work . NMC

[ShellySummers]

You can figure out the mass of one object by figuring out the speed and path another object takes around it. The Stars move around the center of galaxies to fast to stay together. It's not a small number difference. That method gives you the "weight" of a universe. Now that much mass should produce a certain level of light. The galaxies light is way lower then the "weight" says. By Billions of stars. I hope that helped X)

[fieryelf]

I got my theory about dark matter, and the creation of the universe. IMO, basically, the universe was created by 2 universe coming together, one Positive and one Negative if you want, for X reason Positive Matter Starting pouring in the Negative one and Negative in Positive, like Water leaving a bottle to let the air go in, to us, Negative matter would be all that is to create stars and planets and the opposite for the negative world.
Dark matter would be unfilled space, void/positive matter.

[CBALLEN]

I don't agree with you that dark energy exists and neither do many others.There is also a school of thought that says our universe is filled with electricity and plasma, in fact, that could be the gravitational solution of how all the repelling and attracting is actually going on.

[Eugensdiet]

Dark matter does not explain why stars do not orbit in a galaxy the way they would be expected. If it does please show the formula that explains it. If you try you could come up with a bunch of theories that would replace dark matter. A three dimensional map depicting dark matter?you must be kidding.

[ShellySummers]

The velocity of the star. Is used to find out the weight of the universe. It only shows the weight as we can figure it. Not the actual weight. Hence either something radically changes at the galactic level. Or there is something else up there.

[GateMessenger]

.. I read that if there was not a balance between gravity & the solar wind the sun could not exist. There needs to be a balance between output of energy & input of gravity to sustain stars. At any moment if this balance were broken the star would either implode to a black hole or explode into a nebula depending upon the greater of the two actions. So seeing that for every action there is an equal & opposite reaction, I believe the same action creating the solar wind is also producing gravity.

[GateMessenger]

@puncheex How can I convey this in such a short message? At the core of a star or planet is completely opposite to empty space in every aspect. The core is extremely hot, space is extremely cold. The core is under extreme pressure, space is under extreme vacuum. Like any natural force there is an equal & opposite reaction to every action. The action which produces this causes a flow of energy out & a flow of gravity in, like that of low & high pressure air, each rushing to equal out one another.

[GateMessenger]

Yes the theory of gravity is wrong when even noting the universe's inflation. This is why Einstein did not theorize that the universe was inflating exponentially. If Relativity was right then it would have predicted observations. Gravity is a reaction to an action. For every action there is an equal and opposite reaction. The action of the solar wind is equal and opposite to the force of gravity on the sun so it must be the action causing it.

[mikefromspace]

IME MEASURES THE DEGREE OF DEFICIT IN THE SPEED OF LIGHT. SHADOWS OF CONTAINED REST ENERGY EXPRESS ALL VARIABLES AND ISOLATE THE DIFFERENTIAL. TIME IS EQUAL TO THE REFRACTIVE POTENTIAL IN LIGHT. L2=EM if; [(cv) (hv) (1/2mv2)]=L2. All interactions are particle kinetics using DeBroglie waves; λ = h/mv,

where λ is wavelength, h is Planck's constant, m is the mass of a particle, moving at a velocity v.
de Broglie suggested that particles can exhibit properties of waves.

[VirtualParadise]

@fieryelf - ...but then where did those original 2 universes come from? It's a good concept, but you need to reach a 'pin-point' in your theory for something to be considered possible and investigative, and "2 Universes coming together" isn't a pin-point, it just presents a deeper dilemma. A good thought though, plus you never reach the unknown without theorizing first anyway ;-)

[DrJones]

DO YOU KNOW WHAT A GOOD ASTRONOMY DOCUMENTARY SHOULD A DECENT FUCKING NARRATOR!!! For God's sake hire some actors! Stephen Fry, Morgan Freeman or something! People that can actually CONVEY something ORALLY!