Search found 76 matches

by photino
Mon Feb 22, 2010 11:44 pm
Forum: Science
Topic: Richard Feynman videos
Replies: 7
Views: 4691

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...
by photino
Mon Feb 22, 2010 12:25 pm
Forum: Science
Topic: Infinite series in quantum phyics
Replies: 29
Views: 6313

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...
by photino
Sun Feb 21, 2010 12:53 pm
Forum: Science
Topic: Infinite series in quantum phyics
Replies: 29
Views: 6313

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...
by photino
Fri Feb 19, 2010 5:01 pm
Forum: Science
Topic: How can a black hole have electric charge?
Replies: 11
Views: 9953

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...
by photino
Fri Feb 19, 2010 10:47 am
Forum: The Accelerator
Topic: Portal changes
Replies: 8
Views: 1834

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...
by photino
Sun Feb 14, 2010 3:43 am
Forum: Controversial topics
Topic: Several biggest errors of particle physicists.
Replies: 1135
Views: 222226

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...
by photino
Sun Feb 14, 2010 3:09 am
Forum: Controversial topics
Topic: Several biggest errors of particle physicists.
Replies: 1135
Views: 222226

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...
by photino
Fri Feb 05, 2010 10:47 am
Forum: Science
Topic: Can black holes grow?
Replies: 36
Views: 9457

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...
by photino
Thu Feb 04, 2010 3:59 pm
Forum: Science
Topic: Can black holes grow?
Replies: 36
Views: 9457

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...
by photino
Fri Jan 29, 2010 10:38 am
Forum: End Of The World
Topic: Creating "Sparks"
Replies: 164
Views: 82797

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...
by photino
Thu Jan 28, 2010 11:07 pm
Forum: End Of The World
Topic: Creating "Sparks"
Replies: 164
Views: 82797

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...
by photino
Thu Jan 28, 2010 9:03 pm
Forum: End Of The World
Topic: Creating "Sparks"
Replies: 164
Views: 82797

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...
by photino
Thu Jan 28, 2010 7:45 pm
Forum: End Of The World
Topic: Creating "Sparks"
Replies: 164
Views: 82797

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...
by photino
Thu Jan 28, 2010 5:20 pm
Forum: End Of The World
Topic: Creating "Sparks"
Replies: 164
Views: 82797

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...
by photino
Thu Jan 28, 2010 4:04 pm
Forum: End Of The World
Topic: Creating "Sparks"
Replies: 164
Views: 82797

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...