Is dark matter hiding in plain sight?

[DaveC426913]

They are detectable though, right?

Sure, now. They were postulated long before their existence was confirmed. It was the postulation that led to the search that led to the discovery.

 

[twofish-quant]

Sure, now. They were postulated long before their existence was confirmed. It was the postulation that led to the search that led to the discovery.

Same for protons, neutrons, neutrinos, and electrons. For that matter *not* finding something is sometimes as interesting as finding things. It turns out that ether, Vulcan, and "Planet X" (a planet beyond Neptune that was influencing orbits) all didn't exist, but looking for them was useful.

There's a lot about dark matter that bothers me (and even more about the Higgs field that bothers me), but physics advanced by looking for things and either finding or not finding things. Personally I'm hoping that they run LIGO and LHC for a few years and find absolutely *nothing*, because finding nothing would require quite a bit of theoretical effort to explain why nothing was found.

We are just guessing and stumbling around in the dark which is what makes the business interesting.

 

[mintparasol]

Sure, now. They were postulated long before their existence was confirmed. It was the postulation that led to the search that led to the discovery.

Same for protons, neutrons, neutrinos, and electrons. For that matter *not* finding something is sometimes as interesting as finding things. It turns out that ether, Vulcan, and "Planet X" (a planet beyond Neptune that was influencing orbits) all didn't exist, but looking for them was useful.

There's a lot about dark matter that bothers me (and even more about the Higgs field that bothers me), but physics advanced by looking for things and either finding or not finding things. Personally I'm hoping that they run LIGO and LHC for a few years and find absolutely *nothing*, because finding nothing would require quite a bit of theoretical effort to explain why nothing was found.

We are just guessing and stumbling around in the dark which is what makes the business interesting.

Well, I can't argue with either of those replies! Thanks to yourselves and to everyone who replied. It's kind of cool that a question from someone like myself who knows virtually nothing about the technical aspect of physics can get such a lively debate going.
Thanks again, I think I'm returning to my belief from when I first came on here nearly a year ago that gravity has something to do with neutrons or neutrinos...
Regarding dark matter - is there any sign of it in our locality? Like somewhere near enough that a probe we send could arrive and collect data within our lifetimes?

 

[twofish-quant]

Thanks again, I think I'm returning to my belief from when I first came on here nearly a year ago that gravity has something to do with neutrons or neutrinos...

It probably does. It's figuring out exactly what and how that gives people headaches.

Regarding dark matter - is there any sign of it in our locality? Like somewhere near enough that a probe we send could arrive and collect data within our lifetimes?

If dark matter turns out to be made of weak interacting massive particles, then we are swimming in the stuff. Given reasonable numbers, we are looking at 100,000 dark matter particles passing through every square centimeter of Earth every second, and yes people are trying to find them...

http://arxiv.org/abs/0906.5361

https://physicslearning2.colorado.edu/tasi/tasi_2009/Attachments/Schnee_02_200906SchneeTASI2opt.pdf

http://www.astro.caltech.edu/~george/ay20/eaa-wimps-machos.pdf

This is the really interesting thing. It could be that tomorrow someone could publish a paper saying "YES WE FOUND IT", or it's possible that people could be running the experiments for the next million years and find nothing because there is nothing to find.

But in physics, looking for something and not finding it is important, because every month that goes by in which people look for dark matter particles and don't find anything, puts new limits on what is possible and what isn't. One of the most important null results was Michelson-Morley in which they tried to observe the Earth's passage through ether and found nothing. Proton decay is another important null experiment.

But there are also examples where you detect nothing, but there is something there. One of my favorite examples of this are the neutrino beam experiments at Fermilab. There is a beam there that generates massive numbers of neutrinos which then go through Wisconsin to hit a target in Minnesota.

http://www.sciencedaily.com/releases/2005/03/050325231252.htm