I’ve decided that dark matter wants to turn every piece of matter inside out. I think that’s what makes gravity…. Dark matter is gravity without the matter. So take everything out of the universe. No big bang, no matter, no gas, no anything. There wouldn’t be any gravity because dark matter has nothing to pull on. Then put a spec of dust in space…and dark matter already pulls on it and this spec now has a little gravity. Because dark matter is all around, it pulls in every direction, so put a planet in the universe now…and it wants to pull everything to the center. Now fast forward and put more matter in the universe… Everything (that isn’t already attatched to something else) will have gravity all on it’s own in outer space. Just like planets and solar systems colliding, galaxies collide too. Because there is no wind resistance and everything is free to float around in the fabric of space, leads me to think 2 things….Either one day everything in the universe (if it can be counted for) will come together into one ball. The density and mass will be so great it will pull so hard on itself creating massive ammounts of heat and energy that it will again “blow up”. Kinda like when large stars blow up then make black holes. 2 Just like the first part..the big ball of matter will pull so hard on itslef that it will be reduced to something so small and dense that dark matter will pull on it so hard it would be blown out of the other side of where this dark matter is trying to pull everything. But if it’s blown out of the other side, I would think things would start all over again…Just like the infinity sign.

Think of it like magnetism…the opposite poles attract eachother. Now throw in a spec of magnetized dust. Do you think it would one day get stuck in the middle of the “infinity” sign or just keep traveling back and forth between the poles. Put 2 specs of magnetized dust now. Eventually they would attract to each other and become one big piece of dust with a stronger N. and S. pull. Now put a ton of magnetised dust in the infinity sign. would it just travel forever between the poles or would it get stuck in the middle one day and have each pole pulling its opposite pole on the piece of dust. Now give the infinity sign an unlimited ammount of magnetic pull. The harder the poles pulled the more dense the piece of dust would get….so much in fact that it would get hot and the core would turn to liquid.

So the stronger the pull from the outside, the stronger the pull on the inside. Like a knot that gets pulled equally as hard on both sides of the rope…the tighter the knot is. Now this pulls so hard that eventually one side of the rope will break. But the universe is not a rope….so what happens? This applies to everything from planets to stars to galaxies and even to particles.

> The very small and the very big are connected in a fundamental way, and it’s only been through science that we’ve perceived that connection.

‘We’ as the whole WoMankind? Or just the scientific community? ,)
Spiritual (and I don’t think it’s a very bad word (Philip Says), as far as words go) investigators, that go more by the ways of feeling and sensing oneself + Universe, than by logging down and analyzing, have perceived it thousands of years ago.

In no way do I mean that as offense, on the contrary, I rejoice seeing science and spiritual discovering more and more points of intersection.

Dark Matter / Dark Energy: is this what pre-Einstein ether was?
Was Tesla right and Einstein wrong?
Why did Einstein have to twig his original theory on relativity? Could both his theories be wrong?
From what I remember, light rays/waves (and all the spectrum of waves) can self propagate through space because they are made up of magnetic and energy fields (at right angles to each other). What happens if the magnetic field is taken away to the energy field in waves and vice versa? Firstly, can this be done or am I way off here? Does Bark Matter have anything to do with the propagation of magnetic or energy or both fields?

One thing that I do not understand is the big bang theory. Apparently, (from what I hear and read) at one stage in time all matter was condensed and an explosion occurred and the universe developed with all its galaxies, stars, planets etc and due to the big bang the universe is expanding.

Then, where was the dark matter when all was one big mass?
Was the Dark Matter mixed with the Matter we know off, or did the Dark Matter encompass the matter we know off?
Are the galaxies moving apart because the dark matter is “pushing them apart”?

Is Dark Matter expanding too, as the Universe (if it is matter)? If not, then does it mean it was present before, and after the Big Bang?

What if all matter is removed from the universe does it mean that Dark Matter is what is left?

It can’t be a particle or energy, remembering that E=MC2. Am I wrong here?

Is E=MC2 too simplistic?

Assuming that the so-called Pioneer anomaly is real then would any of the proposed theories for dark matter such as WIMPs explain it? Could you have enough WIMPs in a volume the size of the solar system to affect the trajectory of spacecraft to the measured amount? – which appears to be a sunward acceleration for both the Pioneer 10 and 11 spacecraft of 8.74E-10 m/s^2 which is anomalous under existing theories of physics.

Thank you! I knew that someone would 1) have the answer, and 2) know that my questions were serious.

- Jack

No, it’s an interrogative pronoun asking about motivation, purpose, or first cause.

No, it’s an interrogative pronoun assuming motivation or purpose. If there is no motivation or purpose then there is no “why”. Asking the question “why” is only meaningful if you assume that there is a “why” to begin with, something that is far from certain.

A first cause, if such a thing even exists, does not require a “why” because it does not require motivation or purpose. A first cause that was purely random or inevitable from a purely mechanical standpoint does not have a “why” at least in the sense that it is normally asked (that is, asking what the motivation or purpose is behind something). Some religions, including abrahamic ones, assign motivation and purpose to their supposed first cause but this is not universal even amongst religions.

SQUIDs??? So what’s wrong with Superconducting QUantum Interference Devices (SQUIDS) – the users of MRIs and geophysical magneto-telluric devices would be dismayed!

http://www.dnr.state.mn.us/state_parks/soudan_underground_mine/index.html
http://www.dnr.state.mn.us/state_parks/soudan_underground_mine/physicslab.html

When looking at the pictures of the lab remember all of it went down the same small mine elevator you take a half mile down to the lab! Quite a feat in its own right. Neutrino and proton decay research is also done in the lab.

I live in northern Minnesota so I’ve been down and it’s well worth the trip if you are ever in the area. It was just a neutrino lab when I was there last so I plan a return visit this summer.

Rick

[[Why is a metaphysical pejorative used by religiotards against the reality based community when faced with the inadequacies of their own answer “goddidit”.]]

No, it’s an interrogative pronoun asking about motivation, purpose, or first cause.

Hey, “religiotards” is an interesting one. You manage to slander theists and mentally handicapped people in one word.

Or maybe all of dark matter is ordinary matter separated by branes but able to interact via gravity.

Or it’s just spilled fairy dust from some deity’s bag.

We still have a lot of odd behaviors, such as the “hollow” profile of DM “shells,” some ellipticals that appear to have no DM, and so on. MoND would not allow for galaxies with no DM, collisionless particles cause problems as well. Some small irregular galaxies have DM profiles to their core. It’s the variance and exceptions that keep causing the hubub.

Science, no, but math, yes!
Random probability; the same thing that effected how your day came out and how tomorrow will, too. The problem lies in the people who hold a grudge against accepting the answer due to indoctrinated beliefs or the feeling the universe somehow owes them more.

“Consider the Venus of Willendorf”
After studying Native American petroglyphs, I came to the conclusion that there doesn’t need to be a why to this. In any given culture there are artists. There’s always gonna be a person who is left-brained and just wants to create for no reason. Man’s brain has not changed, in this respect, for millenia. So, science can answer this in the fields of Connectomics, Sociology and Anthropology but, ultimately, it’s going to be problematic to answer questions of art with science.

Why is a metaphysical pejorative used by religiotards against the reality based community when faced with the inadequacies of their own answer “goddidit”.

Shame on you. We don’t talk about that kind of stuff here.

Oi!

How do we know that the indirect effects we are seeing are not due to the collective effect of a bunch of fairly small (e.g. dust-sized) particles that we just can’t see with our telescopes, instead of this fundamentally different type of matter?

We’d be able to detect the effects of objects moving through this normal matter. Things would leave “wakes”. Gravity would twist the stuff into clumps, and the clumps would pass between us and other objects, causing little occultations. Bright objects would light up the dust (like zodiacal light).

/\
/ \
/ \
\ /
/ \
/\/\/\/\
/ /\ \ /\ \

Hmm, it is much harder to draw an ascii squid than I imagined it would be in this typeface.

Roughly speaking, the detectors work by measuring two attributes of each particle impact: the heat deposited and the ionization generated (number of electrons knocked free from their orbits). The ratio of these two tells you whether the particle collided with an atomic nucleus or with atomic electrons. The “ringing” looks different in these two cases.

This is how we can look for a dark matter particle without knowing exactly what it is. Any sufficiently heavy particle (~100x the proton mass in most theories) moving at galactic orbital velocities should deposit energy more effectively in collisions with heavy nuclei than with light electrons. Even if we don’t know exactly what the dark matter is, we’re still looking for nuclear impacts and these are actually very rare – most backgrounds from radioactivity transfer energy to electrons.

We bury these detectors underground for the same reason that neutrino detectors are underground – the particles we’re looking for can still get there, but most cosmic rays can’t. We’re particularly worried about keeping away neutrons induced by cosmic rays, since these cause nuclear impacts that can fool our detectors.

Neutrinos are light, depending on their energy they can cause electron or nuclear impacts. They’re not a major issue until we build much bigger experiments.

A couple of comments:

Phil: I’m sorry to complain, but your characterization of the result isn’t quite right. It’s still possible that dark matter could be composed of particles heavier than 100x the proton mass – as Dave C points out, they just need to interact weakly enough. Our result sets the strictest constraints to date on such interactions in this mass range, but lower interaction rates are still possible.

Stuart: As you say, numerous institutions were involved in this work – you can see the bunch on the author list of our preprint (linked above). The spokesperson of the current CDMS experiment is Bernard Sadoulet from Berkeley, with Blas Cabrera as the Co-Spokesperson. The superconducting sensors developed by the Cabrera group are critical components of CDMS’s success, but as a Berkeley-ite I should note that the first iterations of CDMS detectors came out of Berkeley.

Do WIMPs gladly pay you Tuesday for a hamburger today?

(too obscure?)

J/P=?

How can you tell the difference between a nucleus “ringing” from a DM hit vs. one that’s been hit by some other random particle?

Is this anything like neutrino detectors that have to be buried to screen out all of the “normal” exotic particles? Can they tell the difference between DM and neutrinos?

- Jack

It would not be dark. Normal matter is happy to interact with photons and so it would glow. Even cold rocks would glow in the IR and be visible to IR telescopes.

It’s very difficult to make matter not glow.

As for parameterization of ignorance – Seeing I pinched it off someone else, I’m more than happy for you to use it