What is dark matter and does it really matter?

10 comments

What do you think dark matter really is?
Why do you think it is important?
And does it REALLY matter?
Is that so, cosmo?

Then you can tell me what you think it is and why it we wouldn’t exist without it.

I assume you know exactly what it is after spending half your life studying?
Or have you no real answer?

Comments:

I like how you stated your question – very clever!

First – what is dark matter. Dark matter is dark because it is unseen and because it is unknown or more importantly unexplained. Lord Kelvin in the 19th Century estimated that if the Sun burned do to chemical reactions it would burn out in 30,000 years. But as it was discovered that the earth had a history much older than that, there must be something else that fuels the Sun and stars. It was not until nuclear energy was discovered and investigated in the 20th Century that we understood what happens within a star like the Sun.

Dark matter represents a similar mystery. If galaxies represent all the matter that matters, then as Zwicky first discovered we would expect a drop off in the velocities of stars as they orbit further from the center of the galaxy. Instead, Zwicky saw that galaxies have rotation curves as though they were orders of magnitude greater than what we see. The same holds for galaxy clusters of all sizes. So a mystery.

The other part of darkness – unseen – comes from the fact if we have unseen matter all over the place but yet can see back to the beginning of the universe, then the dark matter cannot interact strongly with light. Call that our first clue.

As to the second part of your question. It matters only if faced with a mystery you must find an answer. Of course it would be difficult to accept any of our current physical theories if they cannot explain this mystery, and in turn the validity of any scientific pursuit if mysteries as fundamental as where is matter can be left unanswered. Whether or not it is a big deal once the answer is found – don’t know, but maybe.

{ 10 comments }

Suspend Me Baby!!

Dark matter is the weird black spot in a spot where the sun don’t shine
its important to me but not so much that I took a picture of it and put it on my myspace (oh yes)
no

Elizabeth H

Most of the stuff in clusters of galaxies is invisible and, since these are the largest structures in the Universe held together by gravity, scientists then conclude that most of the matter in the entire Universe is invisible. This invisible stuff is called ‘dark matter’. There is currently much ongoing research by scientists attempting to discover exactly what this dark matter is, how much there is, and what effect it may have on the future of the Universe as a whole.

Scott Hoffman

Emptiness/stateless

I think its important, the universe would be a lot smaller without it.

I think it matters–it helps balance out the universe. Sort of like a person- you have traits that balance you out.

blamay22000

matter that doesnt produce light

The Usual $uspect

I took one look at it on Wikipedia and got confused as hell…

Radius Maximus

A leading theory is that all spiral galaxies rotate faster at the galactic edge. Thus, this dark energy (which doesn’t shine) is contributing to the total amount within the galaxy. Dark matter on the other hand, is simply matter which doesn’t reflect light. Both are important to the field of cosmology. Once we can confirm their existence, we will be closer to unraveling the Standard Model.

cosmo

If there were no dark matter in the Universe, there would be no galaxies and you wouldn’t exist.

We don’t know what dark matter IS, but we know how it acts. It acts like a particle that interacts with ordinary matter only through the force of gravity.

Galaxies are basically made of dark matter, with a little froth of ordinary matter that has fallen into the dark matter gravitational potential well. Without the dark matter, the ordinary matter would not accumulate into galaxies would not form stars, and the Universe would be a much colder and barren place.

stoove

It’s pretty much undetectable matter that is proposed to exist so to make astronomer’s mathematical calculations add up and make sense.

Emmanuel

Dark matter is important in the sense that we as humans are just meant to explore the unknown and discover, but at the same time it is not really important because it is nothing more than just regular matter in my opinion, regular matter that is consisted almost invisible massless particles that we have missed to detect due to our limitation of technology.
Uncertainty reigns in this universe and it always will, but what would science and life be like if we were 100% certain of everything.

Timothy K

I like how you stated your question – very clever!

First – what is dark matter. Dark matter is dark because it is unseen and because it is unknown or more importantly unexplained. Lord Kelvin in the 19th Century estimated that if the Sun burned do to chemical reactions it would burn out in 30,000 years. But as it was discovered that the earth had a history much older than that, there must be something else that fuels the Sun and stars. It was not until nuclear energy was discovered and investigated in the 20th Century that we understood what happens within a star like the Sun.

Dark matter represents a similar mystery. If galaxies represent all the matter that matters, then as Zwicky first discovered we would expect a drop off in the velocities of stars as they orbit further from the center of the galaxy. Instead, Zwicky saw that galaxies have rotation curves as though they were orders of magnitude greater than what we see. The same holds for galaxy clusters of all sizes. So a mystery.

The other part of darkness – unseen – comes from the fact if we have unseen matter all over the place but yet can see back to the beginning of the universe, then the dark matter cannot interact strongly with light. Call that our first clue.

As to the second part of your question. It matters only if faced with a mystery you must find an answer. Of course it would be difficult to accept any of our current physical theories if they cannot explain this mystery, and in turn the validity of any scientific pursuit if mysteries as fundamental as where is matter can be left unanswered. Whether or not it is a big deal once the answer is found – don’t know, but maybe.

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