Dark Matter, Dark Energy

Troubleshooter · 02-23-2005, 01:19 PM

I'm posting this here because it is so new and is reflective of many of the questions that are floating around right now.

We can't see it, but we can see its effects.

http://news.bbc.co.uk/1/hi/wales/south_east/4288633.stm

Astronomers say they have discovered an object that appears to be an invisible galaxy made almost entirely of dark matter.

The team, led by Cardiff University, claimed it is the first to be detected.

A dark galaxy is an area in the Universe containing a large amount of mass that rotates like a galaxy, but contains no stars.

It was found 50 million light years away using radio telescopes in Cheshire and Puerto Rico.

The unknown material that is thought to hold these dark galaxies together is known as 'dark matter', but scientists still know very little about what that is.

Dunlavy · 02-23-2005, 07:18 PM

let's send things into it! *jumps up and down*

Troubleshooter · 02-23-2005, 08:32 PM

One problem, it's not a black whole.

You could probably drive right by it and not notice.

Schrodinger's Cat · 02-23-2005, 10:51 PM

Good example of an unseen phenomena deduced by the application of the scientific method, Troubleshooter!

Physicists and astronomers had to come up with an explanation for the difference between the observed luminousity of a region of space versus the gravitational field generated in that same region. Going by luminousity alone, we shouldn't observe the configurations of galaxies and stars that we actually do. The ratio of luminosity to an object's gravitational field is such that these clusters should be flying apart - not staying together. About 50 years ago a guy named Fritz Zwicky finally figured out that galaxies consist predominantly of matter in some nonluminous form -"dark matter."

There are several theories about the nature of the particles which make up this dark matter. Cosmologists look to the conditions which existed in the early universe for possible models. Likely relics of the early universe are species of stable, weakly interacting particles. One example is the neutrino, if it possesses a small mass. Normally, the neutrino is assumed to be practically massless, but a finite mass is not implausible.

Another possibility is a very massive particle (more mass than a proton!). These particles have been given the acronym WIMP: for weakly interacting, massive particle. Exotic WIMPs such as the photino have been theorized to exist in enough quantity to close the universe. The problem is that there is no guarantee that these particles DO exist. Disregarding this uncertainty, the big bang theory predicts their density today, if they do exist and are stable over the age of the universe. (and you wonder why I choose to live in a black box!

)

Anyhow, I could go on, but I'm starting to detect that glazed look among the members of the audience and I have a bad cold which needs to be taken to bed with a bottle of brandy.

wolf · 02-24-2005, 01:15 AM

Quote:

Originally Posted by Schrodinger's Cat

... I have a bad cold which needs to be taken to bed with a bottle of brandy.

The least you could do is take it out for a nice dinner first.

xoxoxoBruce · 03-08-2005, 07:05 PM

Quote:

Good example of an unseen phenomena deduced by the application of the scientific method, Troubleshooter!

Or somebody needs a new grant or its back to working for a living.

Brown Thrasher · 03-08-2005, 09:19 PM

Sometimes, I think my grey matter may

be that far away. Sorry, need to get my telescope out and see if I can find it..... Get back with you (if) I find it......

02-23-2005, 01:19 PM	#1
Troubleshooter The urban Jane Goodall Join Date: Jan 2004 Location: Florida Posts: 3,012	Dark Matter, Dark Energy I'm posting this here because it is so new and is reflective of many of the questions that are floating around right now. We can't see it, but we can see its effects. http://news.bbc.co.uk/1/hi/wales/south_east/4288633.stm Astronomers say they have discovered an object that appears to be an invisible galaxy made almost entirely of dark matter. The team, led by Cardiff University, claimed it is the first to be detected. A dark galaxy is an area in the Universe containing a large amount of mass that rotates like a galaxy, but contains no stars. It was found 50 million light years away using radio telescopes in Cheshire and Puerto Rico. The unknown material that is thought to hold these dark galaxies together is known as 'dark matter', but scientists still know very little about what that is. __________________ I have gained this from philosophy: that I do without being commanded what others do only from fear of the law. - Aristotle

02-23-2005, 07:18 PM	#2
Dunlavy High Propagandist Join Date: Feb 2005 Location: Forgotten Grove Posts: 117	let's send things into it! jumps up and down __________________ "Two roads divirged in the wood and I, I took the one less travelled by, and that has made all the difference" -Robert Frost "The road to hell is paved with good intentions" -Old proverb

02-23-2005, 08:32 PM	#3
Troubleshooter The urban Jane Goodall Join Date: Jan 2004 Location: Florida Posts: 3,012	One problem, it's not a black whole. You could probably drive right by it and not notice. __________________ I have gained this from philosophy: that I do without being commanded what others do only from fear of the law. - Aristotle

02-23-2005, 10:51 PM	#4
Schrodinger's Cat Macavity Join Date: Jan 2005 Location: A Black Box Posts: 157	Good example of an unseen phenomena deduced by the application of the scientific method, Troubleshooter! Physicists and astronomers had to come up with an explanation for the difference between the observed luminousity of a region of space versus the gravitational field generated in that same region. Going by luminousity alone, we shouldn't observe the configurations of galaxies and stars that we actually do. The ratio of luminosity to an object's gravitational field is such that these clusters should be flying apart - not staying together. About 50 years ago a guy named Fritz Zwicky finally figured out that galaxies consist predominantly of matter in some nonluminous form -"dark matter." There are several theories about the nature of the particles which make up this dark matter. Cosmologists look to the conditions which existed in the early universe for possible models. Likely relics of the early universe are species of stable, weakly interacting particles. One example is the neutrino, if it possesses a small mass. Normally, the neutrino is assumed to be practically massless, but a finite mass is not implausible. Another possibility is a very massive particle (more mass than a proton!). These particles have been given the acronym WIMP: for weakly interacting, massive particle. Exotic WIMPs such as the photino have been theorized to exist in enough quantity to close the universe. The problem is that there is no guarantee that these particles DO exist. Disregarding this uncertainty, the big bang theory predicts their density today, if they do exist and are stable over the age of the universe. (and you wonder why I choose to live in a black box! ) Anyhow, I could go on, but I'm starting to detect that glazed look among the members of the audience and I have a bad cold which needs to be taken to bed with a bottle of brandy. __________________ Macavity, Macavity, there's no on like Macavity, He's broken every human law, he breaks the law of gravity. - T.S. Eliot, Old Possum's Book of Practical Cats

03-08-2005, 09:19 PM	#7
Brown Thrasher self=proclaimed ass looking for truth whatever that means Join Date: Oct 2004 Location: A treehouse Posts: 193	Sometimes, I think my grey matter may be that far away. Sorry, need to get my telescope out and see if I can find it..... Get back with you (if) I find it...... __________________ Let it rain, it eases pain.....

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