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."
August 21 Eastern Time? Wow, great.
I don't know exactly why, but whenever I hear about dark matter, I'm reminded of Zippy The Pinhead.
You can't talk about Wikipedia's flaws on Wikipedia
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.
If you shine a torch at some dark matter what does it become?
Isn't dark matter just all the none illuminated items in the universe?
Rocks and stones and humans and plants and animals and silicon and paper and all these things are what I would consider dark matter, I might be wrong but someone could add some illumination on the subject I would be most grateful.
liqbase
Now dark and normal matter will be one big family again, obviously with court supervision.
See the normal matter's constant oppression, and segrigation of the dark matters, beliefs and people, have exasterbated, the mental condition of the dark matters perception of the reality it's place and purpose in this convaluted society. Thus causing a social backlash againts those percieved by the dark matters to be the sons, and daughters of the overseers and oppressors of former dimensional oppressions, which seed them selves in teh mind of the present black matter....
Power to the matter......
As long as NASA doesn't try to measure DM in metric units, everything should go just fine.
"We are all geniuses when we dream"
- E.M. Cioran
If you put dark matter in your pants, will it feel like any ordinary matter?
Or will there be a pleasant tingling sensation?
In Soviet Russia, dark matter discovers YOU!
Although In Soviet Russia, the presentation would probably be posted before the story.
stuff |
That is what you consider dark matter. There are calculable gravitational effects to those items. Those items are not what astronomers/astrophysicists consider dark matter.
Aren't these people supposed to be deciding whether or not to boot Pluto out of the Planet club?
Seriously, I can't take that whole Pluto thing seriously - there must have been some knobs around back when we had 6 planets and they though Uranus and Neptune shouldn't be included.
6 planets should be enough for anybody
A feeling of having made the same mistake before: Deja Foobar
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.
Cool! Now I can get started on my warp engine!
Yours, Zephram Cochrane
Dark Reflection
So what's the matter, NASA?
Full Tilt
But then I realized I couldn't identify the "normal matter" in that pair.
Will Hannibal Lector please stop eating the brains of astrophysicists.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Dark matter... not to be confused with it's biggot brother, anti-matter.
This just in! 3 out of 4 people make up 75% of the population.
We like to refer to it as "matter of color."
GetOuttaMySpace - The Anti-Social Network
Shouldn't that be "NASA Announces *Announcement Of* Dark Matter Discovery"?
How can one determine how "dark matter and light matter have been forced apart" when we haven't even conclusively determined the EXISTENCE of dark matter? Isn't that a bit like someone saying, "I've discovered why the Sasquatch hides from mankind?"
Don't you hate pants?
Astronomers will announce how dark and normal matter have been forced apart in an extraordinarily energetic collision at 1 p.m. EDT Monday, Aug. 21. - so who is Cartman's father? Is it Officer Barbrady? Chef? Jimbo? Ned? Mr. Garrison? Chief Running Water? Gerald Broflovski? Dr. Mephisto? Kevin, and the 1991 Denver Broncos?
What I mean is, I really wanna know.
You can't handle the truth.
Dark matter feels just like hot grits when you put it in your pants, everyone knows that.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
And on monday August 21, 2006 at 12:00 PM CST WDAF Channel 4 Fox News in Kansas City will air an hour long program detailing the latest news, weather and sports for their local viewing area.
Details as yet are unclear as to the specific content.
This would be terribly interesting if dark matter actually existed and wasn't just a fudge factor necessitated by a poor understanding of how general relativity relates to quantum mechanics.
No announcement until Aug 21st? I guess that is how long they are allowing for the peer review of their results.
"Education is not the filling of a pail, but the lighting of a fire." -- William Butler Yeats
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"...)
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It's never been about how many planets are enough, and it's not just about Pluto. It's about how you define a planet.
It's, in a nutshell, about science: attempting to actually classify and understand the universe. Just proclaiming "ok, I hereby do dub Pluto a planet" is ok for everyday life, but a bit too vague for science. It's like you can talk generically about "radiation" in casual conversation or in super-hero comics, but to a scientist that's uselessly vague. A scientist will be more interested in what _kind_ of radiation (i.e., the exact particle), at what energies, etc.
The same happens in astrophysics. You can't just say "ooh, that's a pretty star", because that doesn't give you much to work with. Is it a planet? An asteroid? A comet? A star? A nova? A white dwarf? What? There are very good reasons to split hairs there, because out of such splitting hairs comes the understanding of what they are and how they work.
E.g., from the splitting of hairs as to how we classify stars came such categories as "white dwarf." In turn, that let us wonder about how big a white dwarf can be, which gave us the Chandrasekhar limit. In turn that told us that when a star goes over (actually it later it turned out that when it's just right under) that limit, it goes *KABOOM* in a spectacular Type Ia supernova. Since it happens at the exact same point, it tells us that every Type Ia supernova is exactly the same as any other one. Which in turn lets us use them to measure distances and velocities in distant galaxies. And from those came a bunch of other astrophysics stuff.
_That_ is why for science it's important to worry about such distinction. Sure, you can get through your everyday life without ever worrying about the difference between Pluto and an asteroid, or between a Type Ia and a Type 1b supernova. But for scientists, it's an entirely different situation.
The informal proclaiming which is what also doesn't scale. When you deal with a whole universe worth of stuff, you have a continuum of things, ranging from individual nuclei all the way to the super-massive black holes in the centre of galaxies. And there are trillions of trillions of them. You can't just go proclaiming for each and every single one of them if it's a planet, an asteroid, or what. You need some rule you can apply there.
A polar bear is a cartesian bear after a coordinate transform.
Hey, we can't account for the mass of the Universe, so we'll just make some random crap up and call it "Dark Matter". We're scientists so they'll believe us.
What. Ever.
Most cold dark "matter" is dark energy, which in turn is dark information. The stuff that nemories are made of.
If this Chandra experiment is successful, we should hook it up to Google to search all the info we don't know about what didn't happen.
--
make install -not war
If this is true, I wonder what it means for the MOND and TeVeS theories that purport to explain many mysteries of the universe without invoking dark matter?_ gravity
:)
http://en.wikipedia.org/wiki/Tensor-vector-scalar
And they *just* made Discover magazine!
1) Turn off lights ...
2) stub toe on matter I can not see
3) patent dark matter and the process by which to make it
4)
5) profit
I'm god, but it's a bit of a drag really...
Will someone please think of the poor helpless penguins !?!
\
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)
Slashdot - Mutual Assured Discussion
The only dark matter is in these guys heads.
Hey, maybe I'm 10, you insensitive clod!!
sorry, couldn't resist (no, I didn't try very hard.)
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Because we can make tests and predictions that can or will prove or disprove notions of Dark Matter. No such test can be made for a God.
Parent is a Troll, Class A.
RS
Shoes for Industry. Shoes for the Dead.
Dark matter is something that effects things gravitationally, but doesn't emit or reflect any radiation. We can tell it's there because the galaxies hold themselves together. In fact, for the galaxies to hold themselves together it has to be something like nine times as common as normal visible matter.
So, if you shine a light on dark matter, nothing happens because the light passes right through it, possibly being defracted by the gravitational pull, but that's it.
The two biggest theories about what dark matter consists of are MACHOs and WIMPS.
MACHOs (MAssive Compact Halo Objects) are basically rocks floating in space that aren't big enough to ignite into a star (thus giving off light), and aren't close enough to another radiation source for us to see them. This theory is encouraged by findings that trans-neptunian objects are a whole lot more common than we thought they were, but is discouraged by the idea that these things don't float in and out of our solar system as often as we think they should.
WIMPs (Weakly Interactive Massive Particles), on the other hand, are a form of matter that just doesn't interact with normal matter except gravitationally. This theory is actually better supported than the MACHO one, but the reasoning is more complex. For instance, when you subtract all of the non-dark matter from our local dwarf galaxies they all turn out to have almost exactly the same amount of dark matter. There is no way to explain this with the MACHO theory. There is some evidence that individual WIMPs are 1000 light years across with a mass of 30 million suns, which is a tough thought to grasp.
Robert Rapplean
www.intellectualicebergs.org
Wake up - the future is arriving faster than you think.
Isn't this what a light bulb absorbs till it's full, and then you must throw it away?
I am the unwilling control for my Origin.
So why don't you explain it for us, instead of just dismissing generations of research with a non-funny insult?
It runs around being desructive with anything that it comes into contact with. It appears to be running a deficit all the time. And it can never be found in the places that you expect it. That reminds me of Bush.
The anouncement is supposed to be "how dark and normal matter have been forced apart in an extraordinarily energetic collision." So somebody is suggesting that dark matter moved, collided with non-dark matter and was forced away, releasing measurable energy in the process.
If nobody knows what dark matter is and if it can't be directly measured or detected then how does one go about measuring its motion and the energy released and know therefrom that it was dark matter that collided with the non-dark matter and not an altogether different unknown substance?
And if it was dark matter that collided with the non-dark matter then does this mean that it's no longer dark matter because it has now produced measurable energy?
It *is* possible that future advances in astrophysics and cosmology will nullify the dark matter argument. It's just as likely that there *is* some sort of mass carrying matter out that that we have yet to identify. Either way it just shows how much we have left to learn.
So, they're going to have a press conference yesterday. Not one fucking word about what was said at the press conference, not one fucking word what the discovery actually WAS.
A new low for slashdot. Did Zonk start smoking crack or something?
Would you like some Dark Matter or Light Matter?
legs or breast?
I would assume this is the Bullet Cluster (1E 0657-56) combined X-ray and weak lensing results that Maxim reported at the Six Years of Science with Chandra Symposium last November. The interesting bit is that in this merging galaxy cluster the hot gas (~ 30%) has collided and been brought to a stop while the dark matter (~ 70%) haloes which are collisionless have passed through each other and are offset from the gas. By plotting the weak lensing image (which shows the total mass) over the X-ray image (which shows the baryons/gas) you can therefore see the existance of dark matter, since the mass is in a totally different place from the gas you can see in the X-ray. This isn't a fundamentally new result but it is a very nice visual demonstration of the existance of dark matter. Rotation curves of galaxies and the temperatures of galaxy clusters had proved it already but with this you don't need to do any maths you can just see it. Page 25 of this 6.5 MB pdf is the one you want for the image.
I strongly suspect that this is about an observation of the "Bullet cluster" (or 1E 0657-56 to it's friends). It's a cluster of galaxies, or rather two clusters undergoing a merger. The merger is significant because the behaviour of dark matter and ordinary matter in a merger is expected to be quite different. The ordinary matter - a plasma of composed (mainly) of high temperature electrons and protons - is collisional and will experience drag as one cluster ploughs through another. This is the component that can be seen with Chandra. The Dark Matter (DM) is collisionless and so will not be so retarded during the merger - it will only interact slowly via gravity. The problem though is you can't see the DM and so this difference is nontrivial to detect. However since it accounts for most of the mass we can measure its gravitational influence. Specifically, General Relativity tells us that the gravitational field will bend passing light. We can measure this through visible distortions in background objects (actually I think in this case it's more like an overall slight distortion over many background objects).
So we have a way to measure where the luminous gas is and where the majority of the mass (expected to be in DM) is. We also have an expectation that these will be in different places. Moreover this expectation is different from that of most "dark matter" explanations that remove the need for additional matter but involve changing the law of gravity, since these always predict that the mass and light will be in the same place. That makes a nice test! The people doing the press release actually did the test and they find (unless their results have changed since I last heard about this) that the mass centre and light centre are significantly offset, providing support for the DM model.
I actually was about to say that, but you beat me to it.
Ignore the "p2p is theft" trolls, they're just uninformed
Yeah dude, that's "insightful". Like no one has ever considered the possibility that our theories of orbits (i.e., the laws of gravity) might be mistaken. Those foolish astrophysicists never thought of that.
Perhaps you'd like to check on the last 30 years of dark matter studies to see why people believe dark matter is the more plausible hypothesis. More recently, see how modified gravity theories like MOND still have a ways to go in both predictive power and theoretical justification before they can compete equally with dark matter.
its dark, but it doesn't matter.
Omry.
So I presume you have a better understanding of "basic" physics? Good! Please point me to some of your research papers so I can educate myself.
Why? Thanks for asking! I'll tell you.
/. readership nonetheless mods the few informative posts up high enough that I can see them and therefore actually learn something interesting.
Because, no matter how many people post pronouncements definitively proclaiming that they, as expert perl programmers or css jockeys or what-have-you, know *quite certainly* that the term "dark matter" is just meaningless mumbo-jumbo, demonstating their amazing mental superiority over the cretinous astrophysics community and its running-dog lackeys in the Mainstream Science Media, the emergent wisdom of the oft-maligned
So thanks to drxray, and thanks to riptalon, and thanks to the readers who modded them up into my view.
This atrangely resambles those cosole pre-release press conferences where nothing new of the product is said at all. Hype machine at work for a science briefing, what's next?
16,777,216 comments ought to be enough for any forum!
Is this an advertisement for Galactus pulling a tablecloth out from under dark matter dinnerwear on "The Universe Has Talent?"
This sig seemed like a good idea at the time....
Dark matter! what would we do without it...
Although the press release says nothing, I would assume that there is some good evidence pointing to the detection of dark matter.
In the August 2006 Discover magazine, there was an interesting piece about Mordehai Milgrom, a physicist who does not accept the dark matter theory. Basically, he has been able to retrofit Newton's equations to allow them to predict on the galactic scale (one of the reasons for the belief in dark matter). Being only an amateur physicist, I can't tell which method is the simpler, the one that only changes the equations, but (almost) no one buys, or the one that postulates the existence of matter that absorbs all electromagnetic energy. I can't wait to hear what this press release tells us.
As long as we're speculating about the discovery, let's not hold back! There's still debate as to whether anti-matter falls up or down. See:
r oject_Physics/Archive4
http://en.wikipedia.org/wiki/Wikipedia_talk:WikiP
If time slows down in gravity, it might speed-up in anti-gravity (the stuff that globs anti-matter together, yet repels regular matter). So here's a wild idea:
Maybe all the anti-matter didn't go away. Maybe it clumped together into large masses, spread out between galaxies. If so, it would help explain the acceleration of the expansion of the universe. If time for anti-matter were accelerated, perhaps all the antimatter stars burned out already, and went dark.
Beer is proof that God loves us, and wants us to be happy.
Then if you're willing to make a mockery of science by defining things by where culture put them, why stop there? Why bother having a science at all, for that matter? E.g.,
- at one point it was in the culture and literature, and all educated people knew, that the sun revolves around the earth, that there are no satellites except the moon, and that a cannonball twice as heavy falls twice as fast. That is, until that Galileo guy came and made a telescope, or actually dropped two cannonballs from a tower. So we should do... what? What do you propose? That for example Jupiter should have been honorarily proclaimed a planet without satellites, just to honour the tradition? That the heavier cannonball be honorarily proclaimed to fall faster, experimental values be damned?
- at one point it was in the culture and literature, and all educated people knew, that the earth is flat. Then came such people as Magellan who actually sailed around it. So what do you do there? Proclaim the Earth a honorary disc, just because that was the established mis-conception?
- at one point it was in the culture and literature, and all educated people knew, that everything is made out of 4 elements and the only thing that separates lead from gold is the proportion of those. I.e., that you could transform anything into anything else -- including the infamous lead-into-gold -- by just finding the right thing to mix it with, as to get the proportions just right for the target element. So we should have done... what, all along? Warped chemistry around that bogus notion, just to avoid upsetting the existing falsehoods? That instead of Mendeleev's table we should have a table with the proportions of the 4 elements for everything?
Etc.
Sad to break your illusions, but science is precisely about proving the existing theories false. That's _all_ that science is about: having nothing sacred or set in stone, and trying to prove the existing explanations false. It's _exactly_ about a "I don't care how many people already learned Newtonian mechanics in school, I don't care how much it would upset tradition to disprove Newton, I have a better theory and the data to support it" attitude. That's how every single discovery or progress have been made: someone had a better theory than the previous one.
The moment you start setting things in stone just because that's the pre-existing mis-conception, or caring more about winning popularity contests ("The alternative is for astronomers to be labeled a bunch of squabbling nuts"), that moment you're not doing science any more. Plain and simple.
A polar bear is a cartesian bear after a coordinate transform.
when we can sail to Pluto, we can revisit the issue.
The Kruger Dunning explains most post on
-Fry"This is a great, as long as you don't make me smell Uranus. Heh
heh."
-Leela "I don't get it."
-Professor "I'm sorry, Fry, but astronomers renamed Uranus in 2620 to end that stupid joke once and for all."
-Fry "Oh. What's it called now?"
-Professor "Urectum."
The Kruger Dunning explains most post on
Actual NASA Photograph of their Dark Matter discovery can be found Here
Kent Simon Multitheft Auto
...but it's too dark to see anything from here. (-: Them's grounds fer complaint! :-)
Got time? Spend some of it coding or testing
...would make that read about right. (-:
Got time? Spend some of it coding or testing
...seconded.
:-)
(-: Just science keeping us in the dark again.
Got time? Spend some of it coding or testing
This is a question still open to much discussion. There are plenty of observed effects (like the abovementioned galactic rotation) which UTTERLY FAIL to fit any (even half-rational) Big Bang theory. This makes Big Bang believers into suckers for superstition. Their god(s) simply went BANG quite early in the story.
Stumble over to a creationism site, they're up to the eyeballs in investigations and arguments. Try Answers In Genesis or the Institute for Creation Research or Geoscience Research Institute for a few examples.
Religion's answers have progressed with (and in some cases before) naturalistic science's.
Typically, the answer starts with words like think about this rather than science's believe or be declared apostate (and be kicked out of research and/or publication).
Sorry, which was the religion again?
...not a substantial amount, anyway. However, testing any worthwhile God involves testing a living being who knows more than you do, and is capable of saying "No", and maybe saying it in complicated ways. It would be like a fish trying to test its owners' vitality, even IQs, yes?
Because there have been (and presumably remain) plenty of scientific individuals and organisations willing to do exactly that. Yes, definitely including (almost specialising in) Atheists.
On top of this, there are many places where you can be killed for picking a diffferent and in your view better candidate in an election.
...the most-of-a-million words which a certain book has in it, which is the closest you'll get to a brief written record of people's interaction with said God, you'll discover that this abbreviation of said God has quite a bit to say about the workings of the universe. There's also what has been "written" on the universe itself. And what use are we while we're refusing to listen to any of this?
Your point was, again?
Got time? Spend some of it coding or testing
This means that they don't burn out as fast.
Got time? Spend some of it coding or testing
Good work! I've put up some more links to Markevitch's work here, and a simplified explanation of this colliding galaxy business:
This Week's Finds, Week238
I'm not an expert on this, so some of the details could be wrong. I'll fix them if corrected (please send email).
Ceres is a planet. Again.
A feeling of having made the same mistake before: Deja Foobar
Ahem.
"Can you see dark matter from your kitchen? Story at 11."