On hadron colliders, dark matter and black holes

[Ascension]

I'll leave that for the Alternate Earth guys, I'm gonna jump into the black hole and map that sucker so no one gets lost when we all get whooshed in

[jfrazierjr]

I'll leave that for the Alternate Earth guys, I'm gonna jump into the black hole and map that sucker so no one gets lost when we all get whooshed in

Actually, given that you have more mass than the computer or paper you are using to map with, I suspect you have those items ripped from your hands.... Of course, I have NO clue what the hell I am talking about, so I am sure Torstan (or someone else) will tell me just how bad I am mangling physics with this absurd statement.

[torstan]

Well objects of different mass fall at the same speed - true of a black hole just as it is true here on earth. However close to a black hole the difference in gravity at your feet and your head (if you are falling in head first) is huge, so your body would be torn apart by the tidal forces as your head gets pulled in faster than your feet - well its almost Halloween, the thread deserves a little gore.

I have no worries about the fact that the LHC threw a mechanical fault. The thing that went wrong is an engineering problem. The physics that we are testing is a theoretical physics problem. The two aren't really related. One thing I can say for sure is that the LHC is unlikely to destroy the world until late 2009 at the earliest as that is the first time it is likely to hit full energy.

Edit: Woot - 2 pips!

[Steel General]

Woot - 2 pips!

WooHoo!!!!!

Congrat's Torstan - we are having an epidemic of multiple rep pips lately.

[Ascension]

Physics schmysics, I'm a mapaholic. Whenever I get a new game I get more enjoyment out of mapping out the whole thing than by playing it...been doing that since MUDs were all the cool thing.

[CC_JAR]

At the same time there have been new developments in space! A satellite experiment called PAMELA has reported that it has found a lot more antimatter than we ever expected to be up there. They've also found that the anti-matter has a distinctive energy. One theory (and the leading one at the moment) is that dark matter is annihilating in the galaxy and producing electrons and their anti-particle positrons with lots of energy. Those then fly through the galaxy and some of them hit the satellite. If this is true then we have just seen the first experimental signal of dark matter annihilations and we have a lower limit on the dark matter mass. That has, unfortunately, ruled out a couple of my predictions, but has opened up some interesting possibilities. So its interesting times for dark matter.

Obviously happy to answer questions if anyone wants to know more.

Ha, that's interesting, before I had even read this part, I had planned on asking what correlation dark matter had with anti-matter, if any. still a valid question though.

Another question I had planned on asking kinda deals with the same thing you're talking about there.
people have already experimented with creating anti-matter right? yet as soon as it's created doesn't it sort of attach its self to matter and null?
so what if dark matter has some sort of this effect?

[CC_JAR]

I had to do it...sorry...

May I now present to you the site of CERN LHC...August 2012.

And as for that pic..
they just had to divide by zero, didn't they?

[torstan]

Sorry CC_JAR I read the second of your posts but not the first. Didn't mean to ignore this question.

Yes, anti-matter does annihilate when it hits normal matter - as long as they are of the same type. So an anti-electron (a positron) will annihilate when it hits and electron, but not when it hits a neutron (for example). The same is true of dark matter, you would expect a dark matter particle to annihilate when it hits another dark matter particle. However the dark matter is so widely spread out, and the particles are so effectively tiny, that the odds of a dark matter particle hitting another are close to zero. Hence there is a lot of dark matter left over from the early universe when it was created. As it is not of the correct form to annihilate with normal matter it is harmless to us.

As for 'normal' anti-matter - we have indeed been playing with that for a long time. You are right in saying that if it hits anything after it has been created then it tends to annihilate. That's because only stable antimatter (antimatter that won't decay on its own) is the positron, anti-proton and anti-neutron. Now those are precisely the anti-matter versions of normal matter - electrons, protons and neutrons. Thus if stable anti-matter hits an atom, there's always something there it can annihilate with. The way around this is to create antimatter and then not let it touch anything. To do this you use a strong magnetic field. This doesn't work with neutrons - they have no charge so don't get affected by magnetic fields - but works well with positrons and anti-protons. If you keep them in a vacuum and use a magnetic field to keep them away from the walls of your vacuum container then you can build up a store of them and hold them indefinitely.

This is what was used in LEP - the predecessor of the LHC. LEP stands for Large Electron Positron collider. So they were colliding antimatter and matter together. The Tevatron in the US - currently the highest energy collider in the world - collides protons and anti-protons. So we are definitely able to create and manipulate anti-matter on a regular basis.

[torstan]

LHC Update

Bad news I'm afraid. The LHC isn't going to turn on again until June at the earliest. The repairs are estimated to cost £14 million and they haven't even finished the full analysis yet. Not the most illustrious start ever. Ah well.

[RPMiller]

That's a bummer... Looks like they'll be putting off destroying the world for quite a while longer.

Interestingly my son is currently studying periodic table in his 8th grade science class. Just helped him put together a Potassium atom last week. Apparently one of the other students mentioned the LHC and the teacher was apparently clueless regarding all the really "deep" stuff that you've been explaining. I told my son he should come here and read up on it. Unfortunately he isn't that excited about it... apparently he doesn't think it is relevant to his currently chosen profession of doctor.... Yea, not looking forward to that college tuition bill.