Register to reply

A rudementary question on dark matter

by hms.tech
Tags: dark, matter, rudementary
Share this thread:
hms.tech
#1
Jan26-13, 03:00 AM
P: 247
I think that there is mass associated with all dark matter in the universe and this mass is much greater than the total mass of the stars in a particular galaxy.

Now, if I were to classify the mass into two categories :
1. visible
2. invisible

How would I carry that out ?

Is dark matter invisible mass or would it be counted as visible mass ?
Phys.Org News Partner Astronomy news on Phys.org
Mixing in star-forming clouds explains why sibling stars look alike
Thermonuclear X-ray bursts on neutron stars set speed record
How can we find tiny particles in exoplanet atmospheres?
hms.tech
#2
Jan26-13, 12:16 PM
P: 247
let me rephrase that, is dark matter visible to the eye ?

Does it emit e.m radiation in the visible region of the spectrum ?
94JZA80
#3
Jan26-13, 12:45 PM
P: 121
Quote Quote by hms.tech View Post
let me rephrase that, is dark matter visible to the eye ?

Does it emit e.m radiation in the visible region of the spectrum ?
"dark matter" does not emit radiation in the visible region or any other region of the EM spectrum...otherwise we would be able to detect it, and not just theorize its existence. the best evidence of the existence of dark matter is indirect - that is, we can't detect dark matter directly, but we can see its effects on ordinary matter. take spiral galaxies for instance - surely their inner regions orbit their respective galactic centers faster than their outer regions...and yet the outer regions still appear to orbit their respective galactic centers much faster than their detectable masses suggest. and so some scientists theorize that there is a substantial amount of "dark matter" in those outer regions (that cannot be seen by any ordinary means of detection) that provide the additional gravity necessary to account for the faster-than-predicted orbits of the outer regions of spiral galaxies about their respective galactic centers.

so your hypothesis that there is mass associated w/ dark matter is in line w/ dark matter theory, b/c even though it does not radiate anywhere in the EM spectrum, its gravitational effects can be detected.

SpaceDreamer
#4
Jan26-13, 01:38 PM
P: 46
A rudementary question on dark matter

The existence and location of dark matter can be inferred by gravitational lensing. It is one of the best ways we have to locate it but even then it's not easy. I do remember a team of astronomers created a map of the dark matter, if I find it ill link it. However dark matter is still classified as invisible matter in your question. Visible matter are things like planets, stars, galaxies, etc. Dark matter is its own form of matter and does have mass and it is predicted to be much larger than the mass of what we can see.


Register to reply

Related Discussions
Dark Matter/Dark Energy Question Cosmology 4
Question about dark matter, dark energy, and MOND General Physics 24
Re: Question about dark matter, dark energy, and expansion General Physics 0
Re: Question about dark matter, dark energy, and expansion General Physics 0
Dark matter doesn't (or what's the matter with dark matter? or pick your lame pun) General Physics 4