Astronomers Make Important Dark Matter Discovery

saudadelinux writes "To quote a press release on NASA's site, astronomers using the Chandra X-ray Observatory have discovered 'how dark and normal matter have been forced apart in an extraordinarily energetic collision.' There will be a briefing at noon, August 21 ET, on this discovery, with streaming media provided by NASA, and some details of the research posted on Harvard's Chandra site just beforehand."

Comments

Nothing to see, move along

[dreamchaser]

How about waiting for the 21st and THEN posting a story. There is literally nothing of substance yet. Oh wait, this is Slashdot. We'll just have it posted again in two days, then on the 21st, then on the 25th, etc.

Re:Nothing to see, move along

[Tackhead]

> There is literally nothing of substance yet.

Not at all. It's got plenty of mass, it's just dark.

Re:Nothing to see, move along

[WED Fan]

> There is literally nothing of substance yet. Not at all. It's got plenty of mass, it's just dark.

Like Oprah.

Re:Question.

[SupremoMan]

Not at all sir. http://en.wikipedia.org/wiki/Dark_matterThis should enlighten you a bit.

In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation (light) to be detected directly, but whose presence may be inferred from gravitational effects on visible matter such as stars and galaxies.

It's a blanket term used for stuff in the universe we think is there but haven't seen because we can not detect it's presence.

Re:The whole day?

[ackthpt]

August 21 Eastern Time? Wow, great.

This is news to announce there will be news at a later date.

the future will be here, any day now

Please record

[4solarisinfo]

Due to recent events at NASA, we'd appreciate everyone helping out by recording the stream of the event, and puttting it... well somewhere you can find it later.

NOOooo...!!!

[The_REAL_DZA]

Someone's giving us ADVANCE NOTICE on Slashdot and you're COMPLAINING?!?!?!
 
I can't count how many times I've read something on Slashdot about something cool that's already happened, just barely, and said "Once again, information I could have put to much better use YESTERDAY!!!
 
Zonk, pay no attention to the criticism; I for one WELCOME some in-advance info (might even vote for it for "overlord"...)

**SPOILER**

[drxray]

They're referring to the Bullet Cluster. It's a merging system where a small cluster is passing through a large cluster leaving a shockwave that looks like a bullet's wake, hence the name.
Dark Matter is collionless, i.e. the DM from the smaller system hasn't been slowed down by the collion and just zooms through. The gas is slowed down. So, the DM and gas are no longer in the same place. We can see the gas in an X-ray telescope (Chandra) and detect the mass by the gravitational lensing effect on the background galaxies.
This is the first time that this has been shown, and it basically disproves the entire category of theories that DM is an illusional caused by us not understanding the action of gravity at long ranges (MOND).

Abstract from a conference talk about this. (PDF)

Re:Question.

[Anonymous Coward]

Because the flow of information is reversed- scientists infer the nature of dark matter from indirect observations of secondary effects. If there wasn't evidence from these secondary effects, then these inferences would be wrong, and scientists would have to come up with a new theory. Sure, there are some scientists who have a lot invested in dark matter, just as there were many prominent scientists who built their careers on the study of luminiferous aether or phlogiston. Time, and science, proved them wrong.

Religionists, OTOH, believe in a Supreme Being a priori, and attribute whatever they cannot otherwise explain to the "mysterious ways" of the divine. The edifice of cosmology would withstand the discovery that there is no dark matter. Would religion be able to withstand the discovery that there is no God?

Re:Think that's bad?

[The Great Pretender]

There was a recent article in Discover that profiled a physist (Mordehai Milgrom) who had come up with modification on Newtons law to explain the planets orbits (forgive me, I'm a layman in this but it seems that dark matter started as a way to explain the weird plant orbits in extended galaxies - I encourage you all to correct me).

"Mordehai Milgrom never wanted to be a heretic. Twenty-five years ago, while poking around for a meaty research problem, he found one that changed the course of his career--and that might yet transform our most fundamental understanding of the universe. His ideas, long relegated to the fringes of physics, where all but cranks fear to tread, have finally become too intriguing for his mainstream colleagues to ignore. Milgrom's heresy? He denies the existence of dark matter, the shadowy and thoroughly hypothetical stuff generally held to make up 80 percent or more of all matter in the universe. Even though dark matter has eluded all attempts at detection, most cosmologists are convinced it must be out there."

So potentially there may not be any dark matter and the vast money being spent on it's pursuit is being wasted. For the record I don't believe in string theory either. I have to say that I would love to subscribe to the simplicity of Milgroms ideas, but it's just a gut check that fitting the theory to the data is better than creating a fudge factor - which dark matter ultimately seems to be.