Does anyone know what 'dark matter' actually is? ?

Question

Add to that 'dark energy' as well. I keep hearing these two mentioned as being important parts of the Universe, but from what I can tell no-one knows what it actually is yet. Am I correct?

Answer 1

Dark matter was a hypothetical form of matter that did not emit light theorized because stars on the outside rims of galaxies have the same rotational period as the stars in the center. A sphere of unseen matter around the galaxy would explain why this is true. Recently Dark Matter was observed in a galaxy collision as the halos of dark matter began to emit some faint electromagnetic waves as they collided. Also when they collide protons a lot of the particles go in one direction despite this violating Newton's Laws so some think dark matter is coming out the other end.

We have observed that the expansion of the universe is not slowing down and is even speeding up. So, theorists came up with dark matter. An invisible force permeating space evenly pushing the universe apart. If you factor in how much energy/matter dark matter and dark energy take up with the energy/matter we know of (the stars, planets, brown dwarfs, black holes, etc.) we get that dark energy takes up 70% of the universe, dark matter 25%, and everything else the remaining 5%.

Dark matter is more or less accepted while dark energy is the predominant theory but is yet to be proved to any great degree.

Answer 2

It is a theoretical matter that can't be seen or detected yet which affect the nature of the universe..  Suggested reading is http://universeguide.com/DarkEnergyMatte...  

Answer 3

It is a "fudge factor" to make sense of observations which do not "jive" with an incomplete understanding of gravity.

Answer 4

You are correct. Studies of gravity indicate that there is much more matter in the universe than is visible. They've invented "dark matter" to try and explain the gravity but nobody knows what it is.

Answer 5

Dark matter is probably rather mundane stuff:

* Brown dwarf stars that shine primarily in the infrared part of the spectrum, however too dimly for our instruments to detect from Earth.

* Rogue planets & dwarf planets running through interstellar space unbound to stars.

* Comets of the same sort that come down to visit the sun once in a while.

The dark matter idea is probably just a theory that there's more of that kind of matter than we have previously supposed.

It's dark energy that's mysterious. Dark energy might be the energy needed to supply the "ground state" in which space exists. As the related Wikipedia article says, it's "the cost of having space."

Answer 6

Scientists say that dark matter must exist to "Balance" the universe, so for every star and planet there is in our universe there must be the same mass existing in dark matter form. I suppose it's the negative and positive of the universe! The only problem with that logic is  where the h**l is it? A very great puzzle, isn't it?

Answer 7

The term "dark matter" was invented by Fritz Zwicky who insisted that the orbital velocities of galaxies were too great to be due to the visible material.  He observed this in the 1930s.  

http://www.symmetrymagazine.org/cms/?pid...

http://en.wikipedia.org/wiki/Fritz_Zwick...

Nobody knows. There appears to be a lot of "dark" material in the form of dwarf stars, maybe big planets and general solid and gaseous stuff lying about as detected at the Mt. Stromlo observatory near Canberra Australia some 15 or so years ago by gravitational lensing observations.  These have been called MACHOS, massive compact halo objects.  

The other candidate for dark matter is WIMPS, weakly interacting massive particles.  A recent candidate for the title of WIMP is the neutrino, which may have some mass.

Maybe the large hadron collider will shed a little light on the matter.    

Answer 8

I Believe the Atom Smasher they are turning on in November will answer many of the questions on Dark Matter,,,,, that is of coarse if tiny black holes engulf the earth!!

Answer 9

Not only do they not know what it is.  There is also no proof any of it exists.  It is just the best theory going around for now.  It will probably (imo) pass away just like the ether and caloric fluid did.

Answer 10

It's a theory to account for discrepancies in calculations of galaxy mass and visible matter. They theorize that most of the matter in any galaxy is not what you see, but what you can't see.  

i.e. Picture a fish in a fish tank.  He sees plants and rocks but not the water.  The fish can only theorize the water surrounding everything.

Scientists see us as the fish and the Universe as the fish tank. Instead of the old saying "We can't see the forrest for the trees" we can now say "We can't see the Universe for the dark matter."