Can dark matter be detected

[anglepose]

there are people at this moment working in deep mines trying to detect dark matter/energy are they searching in vein or is there a possibility they might find somthing.

If so What.

[InfiniteNow]

http://hypography.com/forums/search.php?searchid=55156

[The worm]

deep holes, people wasteing there time!!??what if dark matter is all around us running in currents.how can you look for something if you dont know where too look perhaps the druids knew something about it lay lines are ment to be an energy ,how can we say they werent right .perhaps the theoryof birds usining magnetic firlds to fly around the planet is also wrong we all know magnetic fields can do strange things .what if theres a huge mass of infinite dark matter left over from the big bang and its working in the same way as a magnetic field like poles pushing againest each other is that why the universe is expanding at a greater rate??!!! enough ranting for one day hope you all have a normal life (lol):confused:

[CraigD]

… is there a possibility they might find somthing.

If so What.

Current theory holds that dark matter, if it exists, interacts with ordinary matter at least via gravity. So a possible way to detect it passing through the Earth is to place a “gravity detector” – an awfully precise, complicated device, but in essence simply a weight-measuring scale – someplace ordinary matter rarely passes close by (such as deep underground), and see if it is unexpectedly attracted in an unusual direction. Since dark matter is postulated to interact little or not at all with matter any way but via gravity, it should be possible for it to get very close to the scale’s mass, so a very small mass of dark matter could exert enough gravitational attraction to be detected by a super-precise scale.

 

By placing many such scales at distant sites, recording when unexpected gravitational tugs occur using super-precise, synchronized clocks, and analyzing the data, researchers hope to be able to ignore tugs due to unforeseen, ordinary matter events, and also to be able to tell something about the speed, direction, amount, and arrangement of any dark matter detected.

[The worm]

The worm says

Well all valid points but there all in theroy and not yet proved as we have seen in the past great theroys are not always true wasnt it not that long ago we belived in the world being flat and that god was real (or not yet to be proved could have been an alien life form. another argument regaurding darwin not standing up were not going there today:naughty: )back to plot still falls back to my orginal point ive seen alot of theroys and hipots but no real fact give it another hundred years mabye like the finer points but!!!!!!!!???:eek2:

[CraigD]

…ive seen alot of theroys and hipots but no real fact give it another hundred years mabye like the finer points but!

Alas, Science is not like fine wine – we can’t bottle it up, put in a cool, dry place for a few decades or a century, and have it come out better than it went in! At present, the only way to improve Science appears to be the usual messy process of creating a never-ending succession of imperfect hypotheses and theories.

 

Those who wait for Science to attain perfection may be in for a long wait! :eek2:

 

PS: Welcome to hypography, The worm! You may want to start a thread in the Introduction forum to tell us a bit about yourself, and get introduced.

[InfiniteNow]

how can you look for something if you dont know where too look

By making a reasonable guess based on other clues and information you have. Let's say you lose your keys... it's a bit silly to say that you cannot look for them because you don't know where they are. If you knew where they were, they wouldn't be lost. So, you think of all the things you've done recently and all the places they might be and all the places you'd left them in the past, you widdle down the infinity of options until you have a best guess and you start searching. Then, during the course of your search you learn more and refine your steps until you've either found them or realize they don't exist... :eek2:

[Jay-qu]

Read the latest news article on Polar neutrino observatory takes a big step forward I heard this detector may find a different type of neutrino that has a larger mass and could actually account for dark matter

[Kayra]

Current theory holds that dark matter, if it exists, interacts with ordinary matter at least via gravity. So a possible way to detect it passing through the Earth is to place a “gravity detector”

 

way but via gravity, it should be possible for it to get very close to the scale’s mass, so a very small mass of dark matter could exert enough gravitational attraction to be detected by a super-precise scale.

 

 

Time to show off some of my ignorance for particle physics :confused:

 

Craig, I have a problem understanding some aspects of the expected structure of Dark matter. Perhaps you could clarify some things for me

 

If this stuff does not experience the "Strong Nuclear Force", then it is unlikely to clump up and form normal (albiet dark) matter as we know it. That should mean that it is floating about as clouds of non-interacting particles (not even interacting with itself except by gravity).

 

If this substance is like a "Gas", then will it still be possible for a gravity detector to sense it?

[sanctus]

I don't remember the predicted weight of a particle of dark matter but i remember that if you had a ridicule (<< avogadro/loschmidt) number of those particles (10^3-10^5) and they would interact via the other forces then you would feel them on your hand! So now imagine a cloud of such particles wouldn't there be enough mass so that you can actually measure the effect on a sensible gravity detector?

It's not important if it is a gas or a solid, but the mass.

 

And by the way today I saw a funny calculation, if we calculate the radius of a pseudo hydrogen atom composed of a pseudo electron and a pseudo proton so that the only interaction between them is gravity then the radius calculated with analogy to the Bohr radius turns out to be 10^13 light years (observable univrse 10^10 light years)!

[Kayra]

I don't remember the predicted weight of a particle of dark matter but i remember that if you had a ridicule (<< avogadro/loschmidt) number of those particles (10^3-10^5) and they would interact via the other forces then you would feel them on your hand! So now imagine a cloud of such particles wouldn't there be enough mass so that you can actually measure the effect on a sensible gravity detector?

It's not important if it is a gas or a solid, but the mass.

 

I was thinking that, if these particles do not even interact with each other, then they would not coalesce or condense. What allows things like our sun to exist is the fact that as the particles draw together they collide. Sometimes after they collide, they stick together. Eventually, they clump enough together to start a chain reaction of clumping and we get the solar system.

 

Dark matter does not appear to be able to collide.. even with itself. If this is the case, it would remain a misty.. semi homogeneous cloud that would be near impossible to measure except for it's influence on a larger scale. At lease, that is how it appears to me.

[gccbhu]

I think there are some objects which are moving with the velocity greater than some critical velocity at which they can emit the gravitational waves and those gravitational waves are sheilding waves that shields the matter by which these waves are produced and hence the matter is not visible, called the dark matter.( I may be wrong ,but I dare to say so)

as for as the question for detecting such matter is there , I think in the course of time when the velocity of these objects come down to the critical velocity these objects will be inhibitted to emit the gravitational waves and hence will become visible.

[The worm]

Alas, Science is not like fine wine – we can’t bottle it up, put in a cool, dry place for a few decades or a century, and have it come out better than it went in! At present, the only way to improve Science appears to be the usual messy process of creating a never-ending succession of imperfect hypotheses and theories.

 

thanx craig like your view on science and the fact your open to the truth. my one real concern with the whole dark matter debate is we are still trying to use the normal rules on a totaly un normal force. What if the best way to find dark matter is with a stick or copper rod!!!! People laughed about magnetic fields around the earth and all that it takes is a needle on a thread what if dark matter is the same i know its a simple view but complex is not always the best and i will start a thread of my own cheers:hihi:

[Qfwfq]

People laughed about magnetic fields around the earth and all that it takes is a needle on a thread

Uhm, magnetic compasses were known long before electromagnetism had been worked out.

:)

[CraigD]

my one real concern with the whole dark matter debate is we are still trying to use the normal rules on a totaly un normal force.

Fortunately, dark matter must, by definition, interact with ordinary matter via a very normal force – gravity.

 

The reason some people believe that dark matter exists is that the motion and arrangement of ordinary, “bright” matter – stars, planets, nebulae, etc – appears to be getting a gravitational tug from something we can’t detect. Even “dim” – that is, poorly lit, hard to see – ordinary matter is detectable by its effect on light from bright matter. So, to account for this “missing mass”, it’s proposed to exist as “dark matter”.

 

The only absolute requirement of dark matter is that it effect ordinary matter gravitationally. So, while it may be very weird stuff, in that way at least, we know what to expect from it.

What if the best way to find dark matter is with a stick or copper rod!!!! People laughed about magnetic fields around the earth and all that it takes is a needle on a thread what if dark matter is the same i know its a simple view but complex is not always the best…

What researchers are attempting is not much more complicated than a needle and thread, just much more sensitive.

 

Compared to the other forces, such as the electromagnetic, gravity is very weak – something like a mind-boggling 10^35 times weaker. So finding small disturbances in it is much more challenging than using a compass to find a nail hidden behind a wall. Prior to the invention of electronic stud finders, this (or tapping a lot of test nails into the wall) was how everybody found sturdy places to attach thing to a wall. A stud finder that detected the gravitational effect of a wall stud would begin to resemble the complicated equipment dark matter detection researchers are building.

[damocles]

While the instrumentation is small for the detection of dark matter, isnt the size of the interval that we mewasure the gravitational effect huge? This is gravitational influence that is being measured after all. I would suggest that a detector array might have to be correspondingly large in the volume of coverage.

[Kayra]

So would Dark matter (as currently hypothesized) be able to interact with itself, or anything else, by any means other then gravity?