Can you explain dark matter in laymans terms?

Answer 1

"Dark Matter" is a commonly accepted, but tentative, proposal for a substance whose existence would answer some questions about the behavior of matter and energy in interstellar space that cannot, for the moment, be otherwise answered.

In a few words, "dark matter" is called "dark" because it neither reflects nor generates light. It is considered real matter because masses of it exert gravitational effects on other objects.

"We know it's there, because it attracts other things through gravity, but we can't see it, and don't know much about it."

Stay tuned for more knowledge in years to come.

Answer 2

Astrophysicists discovered something unusual about the rotation of galaxies. In our solar system, the further a planet is from the sun, the longer it takes to complete one revolution. This is consistent with Newton's laws.

In galaxies, that doesn't work. The whole galaxy rotates like a bicycle tire. That is, the stars on the edge of the galaxy make one revolution in the same time as the stars close to the center.

To resolve this, physicists think there must be some other matter that makes up the bulk of the galaxy so that galactic rotation conforms with Newton's laws.

Until very recently, there was no physical evidence of this stuff, and since no one could see it, they called it "dark matter".

I hope that helps.

Answer 3

If you check the set of serious answers to your question, you will find that each states in their own way that the concept of dark matter is completely contrived: it is the possible explanation for an observed activity, and quantified by presumption - very well studied presumption.
I don't think much about dark matter, because first of all, it is a really dumb concept, and second, because there is already a simple explanation for the phenomena.
I document a second universe (commonly called the 'Imaginary Universe'), which, overlays our own. If present, covers all of the phenomena described within the concept of antimatter. It is not a dimension, but a universe where all business starts at the speed of light and goes up from there.
Best of all, though it almost exclusively resides within suns & black holes, it maintains apparent inertia and mass in relation to the remainder of a galaxy's antimatter, and completely replaces the explanations which use dark matter mentioned by my distinguished answering companions.
I know antimatter and the Imaginary Universe are not in vogue because they don't kick out the funding structures like String Thought and Dark Matter models... a question of slavery to fashion, I guess.

Answer 4

"Can you explain dark matter in laymans terms?"

Not easily.

Dark matter is anything that we cannot "see" (which includes "detect" with any kind of instrument).

We can see stars, opaque gas clouds, ionised gasses, floating molecules, etc. We can measure how much of each there is with telescopes, radiotelescopes, X-ray and gammay ray detectors and all sorts of other instruments.

From that, we can estimate the mass and distribution of matter in the Galaxy (for example) and from that we can calculate how fast things should move around in the Galaxy (orbital speed depends on gravity, which depends on quantity of mass -- relatively simple calculation).

However, when we measure the real speeds, we find that things are moving much faster than they should. There must be much more mass than what we can see.

This mass is "dark" (because we can't see it) and it is matter (simply because it has mass).

Astronomers have tried to guess what kind of matter would be invisible to our instruments. Being comical kind of people, they have created two groups of suspects: WIMPS and MACHOS.

WIMPs (Weakly Interactive Massive Particles) are very tiny particles. Neutrinos are a good example of WIMPs: they have some mass (a very, very tiny amount) and they rarely react with anything (99.99999...% of those who arrive at Earth simply go right through the planet without even slowing down).

MACHOs (Massive Astrophysical Compact Halo Objects) are large objects, like wandering planets, made up of ordinary matter but too small (and too far) to be seen.
We can barely detect planets around other stars. Imagine a planet that has wandered away from its sun, alone and dark in the universe.

And yes, the name was created on purpose to end up with the acronym MACHO (the acronym WIMP was already around).

By the way, it appears that the WIMPs are winning (but the game is not over).

Answer 5

Dark matter was invented by astronomers to try to explain a situation that may not exist.
The arms of a galaxy are locked in step with the galactic center.
If the galaxy was a satellite system it would fly apart so dark matter was used to keep it together.
The dark mass would permeate the area of the galaxy and hold it together.

Answer 6

Dark matter is like a black hole in that it can not be seen directly because it doesn't give off light. We only know it exists because of its gravitational effects on the matter we can see. For example, the arms of a spiral galaxy, if left to themselves, would normally wind up around the core and disappear. Because they don't, scientists infer that galaxies are influenced by dark matter around the galaxies which keeps the spiral arms intact.

For more on dark matter, go to http://www.eclipse.net/~cmmiller/DM/
and read "NASA Finds Direct Proof Of Dark Matter at:
http://www.nasa.gov/home/hqnews/2006/aug/HQ_06297_CHANDRA_Dark_Matter.html

Answer 7

No one can and no one truly knows.

The Universe has a glow to it and some area of the universe are DARKER or BLACKER than others. We tend to call that DARK MATTER because photons of light and cosmic rays don't illuminate it.

We don't truly know what it is. We only postulate.

Answer 8

matter that cannot be directly detected but can be inferred from gravitational effects on visible matters such as stars and galaxies.

Answer 9

Dark matter is a unrevealed question like GOD.

Answer 10

It is a substance that scientese made up because they want to sound smart.