Search found 76 matches
- Mon Feb 22, 2010 11:44 pm
- Forum: Science
- Topic: Richard Feynman videos
- Replies: 7
- Views: 14310
Richard Feynman videos
Here are some videos and lectures by the brilliant Richard Feynman , all aimed at non-physicists. Much recommended! The inconceivable nature of nature BBC Series "Fun to imagine" 1: Jiggling Atoms http://www.youtube.com/watch?v=v3pYRn5j7oI&feature=related 2: Fire http://www.youtube.com/watch?v=ITpDr...
- Mon Feb 22, 2010 12:25 pm
- Forum: Science
- Topic: Infinite series in quantum phyics
- Replies: 29
- Views: 37503
Re: Infinite series in quantum phyics
You put your finger on one of the "philosophical" difficulties of quantum mechanics: the state of any system is described by means of a wavefunction. This wavefunction is not directly observable. People have long argued over whether it should be considered "real"... Regarding minimum lengthscales, I...
- Sun Feb 21, 2010 12:53 pm
- Forum: Science
- Topic: Infinite series in quantum phyics
- Replies: 29
- Views: 37503
Re: Infinite series in quantum phyics
Not sure I understand what is being asked here, but 1) Quantum mechanics is based on calculus. Of course physicists use calculus. 2) Yes, in quantum mechanics, you cannot calculate "the position" of something, but you can calculate quantities like the expectation value of the position (the average p...
- Fri Feb 19, 2010 5:01 pm
- Forum: Science
- Topic: How can a black hole have electric charge?
- Replies: 11
- Views: 26950
Re: How can a black hole have electric charge?
If I place an electron and a positron in equal distance from it, will these be attracted differently because of the charge? Yes because they have opposite charges. So one will be attracted by the charged black hole, the other will be repelled. Because well, for two particles to interact electromagn...
- Fri Feb 19, 2010 10:47 am
- Forum: The Accelerator
- Topic: Portal changes
- Replies: 8
- Views: 11110
Re: Portal changes
New LHCb outreach pages http://lhcb-public.web.cern.ch/lhcb-public/en/LHCb-outreach/ LHCb twitter is also back http://twitter.com/LHCbExperiment latest message: The proton beam was stopped with a beam stopper TED just before #LHC tunnel producing secondary particles recorded by the #LHCB at #CERN ab...
- Sun Feb 14, 2010 3:43 am
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1370329
Re: Several biggest errors of particle physicists.
Of course I don't think there's any reason to be worried - especially as looking specifically at heavy ion cosmic rays is an additional safety check on top of many other considerations. Because of RHIC, the quark-gluon plasma phase is much better understood than it was at the time the RHIC safety re...
- Sun Feb 14, 2010 3:09 am
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1370329
Re: Several biggest errors of particle physicists.
Stephen. It seems to me your question is, what if a quark-gluon plasma such as that created at RHIC or LHC heavy-ion collisions "somehow" catalyses a vacuum transition, so that heavy ion collisions at 2.8 TeV/nucleon are somehow more risky than p-p collisions at that energy. Is there cosmic ray data...
- Fri Feb 05, 2010 10:47 am
- Forum: Science
- Topic: Can black holes grow?
- Replies: 36
- Views: 49203
Re: Can black holes grow?
if no information can come out of a black hole, whats when the center of gravity of a black hole is slightly changed by new mass falling in assymetrically, if this would chaange the direction of the vector of gravity which caqn be measured outside that would be also an information coming out of the...
- Thu Feb 04, 2010 3:59 pm
- Forum: Science
- Topic: Can black holes grow?
- Replies: 36
- Views: 49203
Re: Can black holes grow?
Kasuha, yes, that's roughly what I was trying to get at. Chriwi, your argument is also a good one, but note that a probe mass falling in will break spherical symmetry. If the probe mass is actually a spherical shell of matter then the argument holds (and in fact this setup is often deployed to simpl...
- Fri Jan 29, 2010 10:38 am
- Forum: End Of The World
- Topic: Creating "Sparks"
- Replies: 164
- Views: 301456
Re: Creating "Sparks"
2. Read about color confinement - its amazing. Definitely! :thumbup: Now you've understood binding energy, move on to this. Should clarify some things. I guess it might come down to the question; do protons have a weak spot? That when being hit with enough force at the right angle, makes them relea...
- Thu Jan 28, 2010 11:07 pm
- Forum: End Of The World
- Topic: Creating "Sparks"
- Replies: 164
- Views: 301456
Re: Creating "Sparks"
Yes your magnet-like analogy is pretty good if I understand you correctly. To make it simpler just think of a pair of disc-like magnets, I'm sure you've played with some. Snapped together you have a bound state. It's pretty stable. To separate the magnets again takes energy. That's the binding energ...
- Thu Jan 28, 2010 9:03 pm
- Forum: End Of The World
- Topic: Creating "Sparks"
- Replies: 164
- Views: 301456
Re: Creating "Sparks"
And if you ad a sparky energy like a proton beam, you might start a process where it or any other solid matter, turns again into a gas. And like you describe above; the process of an explosion might happen Welll like I said, there can only be an "explosion" if there is a suitable reaction of some s...
- Thu Jan 28, 2010 7:45 pm
- Forum: End Of The World
- Topic: Creating "Sparks"
- Replies: 164
- Views: 301456
Re: Creating "Sparks"
Question is for example, is crystalized concrete a tense field of condensed gas? Not sure what you mean by tense field, I suspect you mean that there is a binding energy. I don't think concrete is a crystal (that would mean that the atoms are arranged in an ordered lattice), but it is certainly a s...
- Thu Jan 28, 2010 5:20 pm
- Forum: End Of The World
- Topic: Creating "Sparks"
- Replies: 164
- Views: 301456
Re: Creating "Sparks"
Of course you're right about this being the end of the world forum... was just concerned as people seemed to be a bit worried. What do you understand by "model" or "proposed mechanism" doesn't my first post of this threat apply to that? Well as you know e.g. for a nuclear chain reaction, you have th...
- Thu Jan 28, 2010 4:04 pm
- Forum: End Of The World
- Topic: Creating "Sparks"
- Replies: 164
- Views: 301456
Re: Creating "Sparks"
Others have basically answered already, but I thought I might add to it a little. 1. To my mind it is irresponsible to throw words with scary associations like "chain reaction" around without having at least the beginnings of a model, because as you can see people get worried. There is no proposed m...