Astronomers Make Important Dark Matter Discovery 223
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."
Hmm... (Score:2)
Re:Hmm... (Score:2)
The real question: Is NASA having fun yet?
Think that's bad? (Score:3, Informative)
Will Hannibal Lector please stop eating the brains of astrophysicists.
Re:Think that's bad? (Score:3, Interesting)
Re:Think that's bad? (Score:2, Informative)
clicky [cnn.com]
Re:Think that's bad? (Score:4, Informative)
I'm not an astrophysist, nor was I involved in the conversation before now, but I did read your linked article :)
Thanks for posting it, btw. I was taking what the parent said for granted, and it sounded pretty bad, but now it looks like it was a combination of bad reading comprehension and badly worded writing. The article you linked to at least, doesn't claim scientists are finding less deuterium than they expected and therefore expect more. Quite the contrary, they're finding a lot more than they expected, and thus are deciding that their theories need to be changed. I quote:
So, they thought there were massive amounts of deuterium was "destroyed" and that not as much was left. Destroyed is a pretty bad way of describing it, but they allude to it in the article that what they mean by it is, "was transformed into heavier elements by stellar fusion." Instead, they're finding out that the amount of deuterium in the galaxy now is only about 15% less than what they thought was the original amount available. They also mention it being in unexpected places, or rather, not distributed evenly, which they find unusual according to current theories.
Nothing to complain about here. Seems to me that the astrophysicists still have their brains intact, and realize their theory needs to be tweaked if it doesn't match the evidence.
Re:Think that's bad? (Score:2)
Re:Think that's bad? (Score:5, Informative)
"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.
Re:Think that's bad? (Score:2)
I suspect you're mistakenly referring to this study of deuterium near the galactic core [space.com], which says that the D-H ratio they found is consistent with other researchers' measurements that imply large amounts of dark matter.
Re:Think that's bad? (Score:2)
Re:Think that's bad? (Score:2)
Please, don't let it be in the form of deuterium ore [imdb.com].
Nothing to see, move along (Score:5, Insightful)
Re:Nothing to see, move along (Score:5, Funny)
Not at all. It's got plenty of mass, it's just dark.
Re:Nothing to see, move along (Score:5, Funny)
Like Oprah.
Hyping machine for a science briefing? (Score:4, Funny)
Re:Nothing to see, move along (Score:3, Insightful)
There is no data, other than what is given in the summary.
If there is no information, why would one want to post the same in
The only discussion that can happen on this would be pure guessworks, and maybe some funny comments.
Mods, mark parent insightful, not offtopic.
Re:Nothing to see, move along (Score:2, Interesting)
NOOooo...!!! (Score:5, Insightful)
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"...)
Re:Nothing to see, move along (Score:2)
Re:Nothing to see, move along (Score:2)
The coolest part is when you extend this comparison to include the Reality Distortion Field. The combination of that with dark matter and cosmology could yield some amazing res
Question. (Score:2, Interesting)
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.
Re:Question. (Score:5, Informative)
Re:Prevailing theories (Score:2, Insightful)
The only dark matter is in these guys heads.
Re:Prevailing theories (Score:4, Insightful)
Re:Prevailing theories (Score:2)
Re:Question. (Score:5, Funny)
Humans, at least alive ones, are not at zero degrees K, and therefore radiate energy, not much, but some. We might be said to be dim matter.
http://en.wikipedia.org/wiki/Dark_matter [wikipedia.org]This link will tell you more.
Re:Question. (Score:3, Funny)
You've never met my ex-wife
Re:Question. (Score:5, Informative)
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:Question. (Score:2)
It is worth pointing out (as I do every time this topic comes up on
Galactic dark matter, which is used to explain the flat rotation curves of
Re:Question. (Score:5, Insightful)
We look for explanations of what's going on, not just saying "it's God. Don't go there." Think of dark matter as a placeholder, not the end product. Over time, we should find a reasonable explanation of what's causing the discrepancy, at which point it will just become part of the "normal" physics.
Re:Question. (Score:3, Interesting)
Re:Question. (Score:2)
Re:Question. (Score:4, Funny)
Apparently, when you seperate dark matter from normal matter you get an extraordinarily energetic collision, whereas when you seperate a Christian from God you get a rational thinking being.
Re:Question. (Score:3, Insightful)
Not at all. Irrational people will continue to believe what they always have, and continue to be irrational, whether or not religon is involed. It just gets popularly scapgoated, by people who have some ax to grind in the first place.
Re:Question. (Score:3, Insightful)
There is no secondary 'effect' that infers the existance of god.
Be that as it mey, what this means is 'we have observed and effect, now we are looking for the cause.
They seem to be making head way.
Something falling is an effect of gravity. Oberving that effect is what lead to discovering all the cool stuff about gravity.
Re:Question. (Score:2)
I am an atheist and believe in a god-free universe. But if you were a deist, this would be a pretty reasonable explanation. the nice thing about deists is that they are rational and do not believe in miracles, unlike some of the superstitious who believe in god(s).
WRT the article - I can'
Re:Question. (Score:5, Insightful)
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:Question. (Score:3, Insightful)
Scientist: There's something we can't explain. Let's try to figure out what it is.
Believer scientist: There's something we can't explain. Let's try to figure out what God did.
Re:Question. (Score:3, Informative)
Re:Question. (Score:3, Insightful)
And next year, even better.
And next century, better still.
You may now switch argument tactics to "How can you trust science if it keeps changing its answers! Religion has been giving the same answer for thousands of years!"
Re:Question. (Mod Parent Down) (Score:2)
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
Re:Question. (Score:2)
There is no difference in that both are theories. However there is a big difference in the fact that one is just a theory, while the other is a scientific theory, and the difference between the two, is that one can be tested and has a chance of eventually being proven wrong. I'll let you figure out
Re:Question. (Score:2)
Hypothesis: thou art moron.
Re:Question. (Score:2)
A good logical question. I will attempt to answer it here. While both dark matter and God are both human conjecture, dark matter (and other scientific based conjecture) is different from believing in God in the following ways:
Re:Question. (Score:2)
Just for starters, you're not going to get some well-organized community deciding it's a good idea to kill you simply for offering a different and better explanation.
-
Re:Question. (Score:2)
I think this is a fair and interesting criticism - but easy enough to answer.
Science is the accumulation of human knowl
Re:Question. (Score:2)
Nobody has yet been killed for not believing in dark matter.
Re:Question. (Score:2)
That's the difference between faith: knowledge not proveable (or disproveable); belief: knowledge dis/proveable, but not actually dis/proven; and fact: knowledge dis/proven.
The difference results in fact more reliable than faith, but faith more important than fact. The difference also means the two are compatible, even when apparently contradictory, but that faith must yield to fact when faith can still exist without being dis/proven as fact.
Re:Question. (Score:2)
I should think that would be obvious enough, but if you need an analogy, here's one:
A man walks into a dark room and stumbles over a chair. The chair bumps into something and there is a sound of something shattering.
Scenario 1: The man designate
Re:Question. (Score:2)
How about: because there is evidence to suggest it exists. That's entirely different from believing in magic.
Seeing something move as if it is being pulled by gravity, and knowing that gravity is only known to come from matter, then conluding th
Re:Question. (Score:2)
Seriously.
A quick tutorial on Dark Matter (Score:2)
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
Together again (Score:4, Funny)
Measure DM (Score:5, Funny)
In Soviet Russia 101 (Score:2)
Although In Soviet Russia, the presentation would probably be posted before the story.
Please record (Score:5, Funny)
Warp 1 Mr. Sulu (Score:4, Funny)
Cool! Now I can get started on my warp engine!
Yours, Zephram Cochrane
Re:Warp 1 Mr. Sulu (Score:2, Funny)
That's anti-matter you nipplehead.
Re:Warp 1 Mr. Sulu (Score:4, Funny)
Re:Warp 1 Mr. Sulu (Score:2)
Re:Warp 1 Mr. Sulu (Score:2)
Re:Warp 1 Mr. Sulu (Score:2)
The importance (Score:4, Funny)
It's not "dark" matter (Score:5, Funny)
We like to refer to it as "matter of color."
Typo in title (Score:2)
Re:Typo in title (Score:4, Funny)
Re:Typo in title (Score:4, Funny)
-
August 21 (Score:2, Funny)
Details as yet are unclear as to the specific content.
Re:August 21 (Score:2)
Really, this is an annoucement so you can get into the telconference.
Tanks for the Nemories (Score:2)
If this Chandra experiment is successful, we should hook it up to Google to search all the info [westnet.com] we don't know about what didn't happen.
I can make my own dark matter (Score:2, Funny)
2) stub toe on matter I can not see
3) patent dark matter and the process by which to make it
4)
5) profit
Will Someone (Score:2)
Will someone please think of the poor helpless penguins !?!
Dark Matter (Score:4, Funny)
Nice visual demonstration that dark matter exists (Score:5, Informative)
I would assume this is the Bullet Cluster (1E 0657-56) combined X-ray and weak lensing results that Maxim reported [harvard.edu] at the Six Years of Science with Chandra Symposium [harvard.edu] 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 [harvard.edu] is the one you want for the image.
Re:Nice visual demonstration that dark matter exis (Score:2)
I love this place (Score:2, Insightful)
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
Is This an Advertisement? (Score:2, Funny)
Actual NASA Picture of Dark Matter (Score:3, Funny)
Re:The whole day? (Score:3, Interesting)
Re:The whole day? (Score:5, Funny)
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
Come off it, you know what it feels like (Score:2)
Re:Come off it, you know what it feels like (Score:2)
Not at all (Score:5, Insightful)
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.
Re:Not at all (Score:2)
Does it really matter though? Planet, to my understanding, had historically been used to distinguish between observable objects in the night sky that move (planets) and don't move (stars).
I don't think that a planet is something that needs a precise definition. If there were some propert
Re:Not at all (Score:3, Informative)
Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables for about five decades, until several other asteroids were discovered. You are arguing that Pluto should continue to be listed as a planet for the SOLE reason that it has the same "tradition in the cultures" for about seven decades.
[Ceres/Pluto] is merely
Re:Say What? (Score:2)
Oblig. "insensitive clod"... (Score:2)
sorry, couldn't resist (no, I didn't try very hard.)
Re:Say What? (Score:2)
Re:Say What? (Score:2)
By your reasoning, if two solar systems passed close enough that one star captured a jupiter-sized body from the other star, you would not consider that body to be a planet anymore?
Re:Say What? (Score:2)
If this reasoning isn't sound, what seperates an asteroid from a planet? Mass? Size? No, there is a bit more to it than that. How the body was formed plays a large part in that, and if you've paid ANY attention to why Pluto's status as a planet was up for debate, you'll see that it's origins are the main topic of debate.
Please research what scientists call planetary formation before you call their reasoning stupi
**SPOILER** (Score:5, Informative)
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. [cosis.net] (PDF)
Re:**SPOILER** (Score:2)
-drxray
Re:**SPOILER** (Score:2)
Re:**SPOILER** (Score:3, Informative)
Re:**SPOILER** (Score:2)
Re:**SPOILER** (Score:5, Informative)
The most relevant is probably http://arxiv.org/abs/astro-ph/0309303 [arxiv.org] .
Re:**SPOILER** (Score:2)
Umm... these observations only "disprove" MOND if you believe that MOND and dark matter are mutually exclusive theories.
Disclaimer: I hold no allegiences to either theory. I just find it irritating when people talk about "proving" or "disproving" theories when they're doing nothing of the kind.
Re:How can one be certain that it's dark matter? (Score:2)
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?
If there isn't a way to find out if it's "an altogether different unknown substance", then, for all intents and purposes (and sanity), it's not.
Re:How can one be certain that it's dark matter? (Score:2)
Re:In case anyone is wondering what this is about (Score:2)