If This Type of Dark Matter Existed, People Would Be Dying of Unexplained Wounds (sciencemag.org) 106
sciencehabit shared this article from Science magazine:
Dark matter, the mysterious substance that makes up most of the mass of the universe, has proved notoriously hard to detect. But scientists have now proposed a surprising new sensor: human flesh. The idea boils down to this: If a certain type of dark matter particle existed, it would occasionally kill people, passing through them like a bullet. Because no one has died from unexplained gunshot-like wounds, this type of dark matter does not exist, according to a new study... [It's title? "Death by Dark Matter."]
This experiment doesn't rule out heavy macro dark matter altogether, says Robert Scherrer, a co-author and theoretical physicist at Vanderbilt University. It merely eliminates a certain range of them. Heavier macro dark matter would not occur frequently enough to measure, notes Katherine Freese, a theoretical physicist at the University of Michigan, and other forms wouldn't kill people. "There is probably still room for very heavy dark matter," says Paolo Gorla, a particle physicist at Italy's underground Gran Sasso National Laboratory, who is not involved with the study.
This experiment doesn't rule out heavy macro dark matter altogether, says Robert Scherrer, a co-author and theoretical physicist at Vanderbilt University. It merely eliminates a certain range of them. Heavier macro dark matter would not occur frequently enough to measure, notes Katherine Freese, a theoretical physicist at the University of Michigan, and other forms wouldn't kill people. "There is probably still room for very heavy dark matter," says Paolo Gorla, a particle physicist at Italy's underground Gran Sasso National Laboratory, who is not involved with the study.
It is title? (Score:1)
Keeping the standards up as usual, Ediduh Javaid.
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Basicly, there is an detector of about 50,
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https://youtu.be/oNxr_mrEoRo?t... [youtu.be]
Wounds, Like Split DNA? : ) (Score:2)
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If a small particle of dark matter is traveling slowly, we won't notice it any more than we would a molecule of nitrogen hitting our skin. No gunshot holes. And that assumes that dark matter can interact with other our bodies. Neutrinos travel VERY fast, but we don't see people dropping dead peppered with neutrino
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Neutrinos travel VERY fast, but we don't see people dropping dead peppered with neutrino holes.
That is because neutrinos almost never interact with matter, they are close to massless, and are exceptionally tiny. When you combine all three features, it's no wonder people are dropping over.
However, this type of dark matter, if it exists at all, is large, heavy, and energetic. Looking at the pdf of the study, they estimated this type of dark matter could be several microns in size and weigh up to 50 kg. If
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Would it leave a mark if it doesn't interact with matter? Part of the reason that neutrinos go right through us and some light years of lead is that they only interact through the weak force (and gravity), so basically have to directly hit an atom as the weak force is such a short range force.
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But might seriously fuck up one of a pair of atomic clocks if it is common enough to "matter"?
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The "oh my god" particle, https://en.wikipedia.org/wiki/... [wikipedia.org] had the energy of a baseball traveling at 58 mph. Being a particle, likely a proton, pretty sure it would go straight through somebody and severely mess with any DNA in its way.
There's been a further 72 similar events observed.
If these particles don't kill people, why would dark matter particles kill people? Are they supposed to be bullet sized?
Instead of "Death by Dark Matter" . . . (Score:2)
. . . can I have "Death by Snu-Snu" instead . . . ?
Well, clearly... (Score:2)
Well, clearly they would not be unexplained because this hypothesis explains them, unless these spontaneous deaths altered the timeline so as to prevent the creation of this hypothesis.
Though, if anything, I'd expect people to look more closely into these unexplained deaths in such a universe.
Though maybe such a preponderance of random deaths might have slowed down the developments of hominids to the point where you could still refer to them as 'People' but they wouldn't have developed sufficient scientific
Another Interesting Natural Constraint (Score:5, Funny)
This joins a couple of dozen different types of natural observations that constrain what dark matter is. We know it exists, because of its gravitational effects, and can map its distribution in the Universe that way, but we have no idea what it is. Many, many theories have bitten the cosmic dust at this point as observations have piled up that eliminate by showing their predicted consequences do not exist. Hint: if you just thought of something you think dark matter might be, you are wrong - it will already be disproven, usually trivially so.
We are beginning to run low on plausible theories for something that appears to interact with everything (and itself) by gravity alone and nothing else.
BTW, if dark matter is evenly distributed in space, then based on known local galactic density an average adult (world average) would have 4*10^-20 grams of dark matter in their body at any moment, for North Americans 30% more, and for slashdotters probably somewhat more still.
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Interesting, but based on long observation, the notion of something in our bodies of unknown properties, and not subject to physical analysis, is an idea to be immediately dismissed out of hand here on Slashdot.
Bonus karma if you work in a reference to Dawkins.
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Except it cannot be evenly distributed because it interacts with matter gravitational. Think about that for a minute.
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It did not take me a minute to realize this is ignorant BS.
DM can be evenly distributed on a small enough scale. Like, within the galaxy itself. Dark matter particles are bound gravitationally to the Milky Way and thus have average velocities somewhat less than the galactic escape velocity which is 550 km per second. No structure within the galaxy has gravitational binding energy high enough to significantly cluster these particles that are in galactic orbit.
As I warned in my post the brilliant insight that
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DM can be evenly distributed on a small enough scale. Like, within the galaxy itself. Dark matter particles are bound gravitationally to the Milky Way and thus have average velocities somewhat less than the galactic escape velocity which is 550 km per second. No structure within the galaxy has gravitational binding energy high enough to significantly cluster these particles that are in galactic orbit.
If they're in orbit then they are by definition not evenly distributed.
No structure within the galaxy has gravitational binding energy high enough to significantly cluster these particles that are in galactic orbit.
It doesn't have to do that to make them not evenly distributed. All it has to do is measurably redistribute them. If they interact with gravitational masses, which are themselves not evenly distributed, then they can't be evenly distributed around the galaxy.
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As I warned in my post the brilliant insight that flashed through your head was stunningly wrong.
..... they instantly see things that hundreds of astronomers working on this for years have missed.
Interesting. Then maybe we should approach the problem with thousands or millions of astronomers while it is still possible for humanity to do so.
Once we get set back by the overwhelming forces of nature that constantly occur in time, we'll be like the dinosaurs: another fossilized fuel supply for a newer iteration of life on earth whose days are numbered. To figure out the big picture....or the little picture, as the case may be, we need to be less divisive, self-serving, egocentric in the approach. A
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What I don't understand is, why is dark matter uniformly distributed in space? If gravity is the (only) way it interacts with non-dark matter, it should then cause it to accumulate in stars and other massive objects, no?
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Dark matter isn't uniformly distributed in space at all, it's bunched up in ways that hold galaxies together. What it isn't is all sucked down to the middle like the central black hole, and this is because as best we can tell, dark matter is completely collisionless. This means it has no way to shed excess momentum, so it never forms macro scale compact objects. At least that's the idea.
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this is because as best we can tell, dark matter is completely collisionless. This means it has no way to shed excess momentum, so it never forms macro scale compact objects. At least that's the idea.
THANK YOU, good sir! This is really a very clear and succinct explanation that makes a lot of sense. Thank you very much for having taken the time to explain it - I am genuinely very appreciative.
Re: Another Interesting Natural Constrai (Score:2)
So far dark matter is the theory that best fits the observations. Why should it be rejected?
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Gravity is not a fundamental force. Gravity is just an artifact of space and time interacting.
Space is far more complex than just saying, "these two points are 12 inches apart", and time is far more complex than, "these two events happened 12 seconds apart". This becomes semi-obvious close to the speed of light... but what is the opposite of the speed of light? Is there an absolute zero "speed"?
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but what is the opposite of the speed of light?
The speed of dark?
HeeHaw Mike got it in Frisco (Score:2)
It's been a long time since I studied physics (Score:2)
But, on the face of it, it seems one would want to be careful speculating about the properties of a theoretical substance we've been unable to measure or even observe.
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Slashdot problem (Score:2, Insightful)
At time of writing there is about 37/40 posts above that are basically anti-Jewish / neo nazi type posts. If it's basically approaching 80%+ of posts Slashdot has a serious problem on its hands.
They seriously need to update the regex posting filters. Or, if a post contains "f--k the Jews", perhaps it should at least start at -1. It's getting out of hand and this isn't really a laughing matter anymore.
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Who cares if there is a filthy sewer under the street as long as I never go down there?
Odd way to measure (Score:3)
This is borderline ridiculous. There are much better ways to measure these kinds of effects than to claim the particles would cause damage in people.
We have all these detectors and big tanks of fluids all over the world, tailor made to precisely measure these kinds of interactions (mainly for cosmic rays and neutrinos), so why would scientists want to use imprecise measurements such as undefined damage done to human bodies? How do you even prove the damage was done by particles from outer space anyway?
I'm not sure I'd call this science anymore...
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All particles are "from outer space."
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Terrestrial gamma ray flash from lightning [wikipedia.org]. Also lightning generated neutrons [arstechnica.com].
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OK, now look up "conservation of energy" and figure out if what you said makes sense, or if I'm just going to point out that you didn't create any new particles you only rearranged them?
And check your links better. That link to the Arse of Tech where Pedo Peter Bright works doesn't say what you seem to think it says. It describes the theory you're pushing, but it also says that the evidence from this single study basically disproves that. You're confusing the fact that the researchers wanted to prove that w
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It is what they call a natural experiment. Nothing at all ridiculous about that. In fact aside from the few particle detectors we have built to look for these, all of our sources of data on DM are natural experiments.
Astronauts in space see light flashes caused by cosmic rays. The hypothesized effect would be similar (using the body as a detector) but scaled up many orders of magnitude in deposited energy (and fortunately scaled down in frequency).
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Now Having Read Some of the Underlying Papers (Score:4, Interesting)
What this line of work is distinguishing between the two fundamental options for explaining the non-detection of dark matter beyond gravitational mapping. One is that they are extremely weakly interacting (possibly zero interactions it is increasingly appearing) beyond gravity, or that that do interact but are simply really rare. In the latter case, since we know the mass density in the galaxy, they must have a lot of mass -- at least 100 grams and less than 100 billion tons.
The "no dead people" constraint creates a constraint of less than 50 kg (and so 0.1-50 kg) (to make he injury of passage small) or more than something like 1000 kg (to make it sufficiently rare). Actually I think the extended "no dead people" constraint (considering smaller and smaller injuries) combined with other constraints (mineral observations) make the lower ratio range quite small, logarithmically speaking (like 100-1000 grams or something). The >1 tonne Macros are still on the space-table.
The effect of one of these cosmic messengers of death would be more precisely like a thin filament of high explosive that stretches through your body detonating.
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Here is another reason why we see no dead people. There is no dark matter in our solar system or it's vicinity. A fact that is pretty easy to deduce with a bit of logical reasoning.
Remember dark matter makes up 85% of the matter of the Universe (assuming the figure in Wikipedia is the current assessment for the amount there is, regardless it is a high percentage). We know it interacts with ordinary matter gravitationally because that is how we have "detected" it in the first place when we tried to explain t
Re:Now Having Read Some of the Underlying Papers (Score:5, Informative)
Reasoning without bothering to do the math is in no way logical.
In a post above I caution against posting wild-ass guesses about dark matter. Posting your conclusion about dark matter without (clearly) bothering to do any reading on the subject, or doing even any arithmetic, at all is a sure fire way to be wrong or at least silly. I posted data on the local density in the other post above (in astronomical terms 0.01 solar masses per cubic parsec), and it is available by Googling.
Believe it or not, astrophysicists have actually examined the consequences of dark matter in the local region and its measured mass density in the Milky Way. The key problem is your unspecified value of "significantly". I think you have in mind the tautological definition of "significant means something too low to detect in the solar system gravitationally" and you would be correct. But that figure is far higher than the average mass density of dark matter here. Inside the orbit of Pluto the amount of dark matter is 10^-13 solar masses, or one millionth of the mass of the Moon. We do not know the amount of normal matter in the Solar System to this precision. We would need to add something 10 orders of magnitude to our ability to measure it, before this became a constraint).
https://science.slashdot.org/s... [slashdot.org]
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Perhaps they have (Score:2)
I doubt, that our policemen would suspect dark matter when encountering such a death, they'd suspect ice projectiles (frozen bullets) or other methods first.
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Cops around here would just shrug and say, "It's a mystery" and file it by date in the cold case bin.
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I doubt, that our policemen would suspect dark matter
They just file it under black people.
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Cops do not determine cause of death.
No one's died of unexplained gunshot-like wounds? (Score:1)
Clearly the Mafia / Russians / CIA got to these physicists before anyone could put together Oswald and magic dark matter.
A test for this stuff, micro-black holes, etc.. (Score:3)
I propose the following experiment. Get about 20 tons of steel pipe in thick sections that can nest. Support them on the ends with bearings and a clockwork drive. Turn each piece VERY slowly at a different rate, such that they only overlap at the beginning of the experiment, and perhaps again at the end. Let them sit in a temperature controlled environment (or just heat them all to a common temperature (which is cheaper))... after a few decades, take the whole thing apart and scan the entire surface of the outside layer for holes using a tunnelling electron microscope.... if holes are found, scan the inner layers for matching holes... any hole that goes through multiple layers can tell you the date and direction of the source.
You don't even have to grind the surface first... you could do it at the end, it wouldn't really matter.
Elegant, and affordable. What do you all think?
Of course an even cheaper experiment would be to take very old structural steel and polish and scan it. The older, the better.
Maybe,,, (Score:4, Funny)
these bullet-style wounds are not found because those who are hit by the particle also spontaneously combust and burst into flames? ;-)
Spontaneous Combustion? (Score:2)
JFK (Score:2)
So Lee Harvey Oswald didn't really shoot Kennedy?
Incoming new SyFy movie (Score:2)