Modern and Theoretical Physics

Is the statement true that, "All space still exists, therefore all time still exists." I.E. the past and the future still exist, you are not born yet and you're already dead.

Hi, Im new to this time travel stuff and wondered, if someone went back in time, would they see themselves living in that time or would they become part of that time again?

IT IS A POLL! I would like to learn if you've ever heard of the positive charge atomic form-factors before my asking this question. The positive charge atomic form-factor fnn'(q) stands at the nucleus charge Z and describes the positive charge cloud in atoms for the elastic (n→n) scattering channel at large angles. It also describes the inelastic scattering channels - "hitting" nucleus by a projectile excites an atom (n→n'): dσn→n'(q)/dΩ ~ |Z⋅fnn'(q) - Fnn'(q)|2 The elastic and inelastic positive charge atomic form-factors are entirely determined with the atomic wave functions ψn(r) and they have nothing in common with the Hofstadter form-factor describing …

If you convert energy into matter, what does it become exactly? Complete atoms, or a whole bunch of randomly loose subatomic particles?

I'd just like to say that, before you get the wrong idea, this thread does not concern dimensions that extend beyond the human experience. Human experience typically tells us that there are three spatial dimensions - and why does the human experience tell us this? - because it presents us with an idea that is really easy for us to get our heads around. There's an a left and a right, an up and a down and a forwards and a backwards. When we consider the physical situation in which we find ourselves, this description of dimensions could not be simpler. The word dimensions comes from a Latin word that relates to the action of measuring. The…

Just recently, I became very interested in the SSC. After looking at some of the plans and details, I couldn't help but wonder why the project has not been reopened... I was thinking of possibly either: 1) Getting a nation wide petition signed to reopen construction of the SSC, or 2) Work as hard as possible in possibly finding quite a number of investors, so I could privately reopen the construction and then staff the place once it is built. I figure that the plans would have to be redrawn, however, because times have changed, and the SSC could use quite a number of improvements... Anyway, i wanted to know what you had to say about the idea. Maybe I overlooked …

http://video.google.com/videoplay?docid=7136440703094429927 I just watched it---I read the transcript long ago but never watched the video, where he is telling all the stories. I was impressed. Maybe would like to watch more. Is there some other Feynman online video that you think is especially good?

Dear colleagues, In this thread I would like to share with you my findings in the so called renormalization prescription. Very briefly, I managed to reformulate the QED in the way that excludes appearing infrared (IR) and ultraviolet (UV) infinities. As you know, in all renormalizable theories one has to carry out the renormalization procedure. In my opinion, such a prescription is nothing but discarding corrections to the fundamental (phenomenological) constants. This is mathematically unacceptable. By chance it may work, but not obligatorily. In my work (http://arxiv.org/abs/0811.4416) I managed to make this as evident as possible. I reduced the problem t…

on my wanderings through the intar web i found this cool flash to help you visualise 10 dimensions in our universe. it sorta makes sense. http://www.tenthdimension.com/flash2.php Caution: may cause explosion of brain and reduce you to a gibbering vegetable.

What is this string theory dealing with 11 demensions by Einstein all about? Any ideas on where I should start looking online? Merged post follows: Consecutive posts mergedWow very complex. Can anyone give me a small basic description?

As a person moves faster, time is relative and slows down, but i was wondering if that was only for time around the person? As a person would near the speed of light, and time slow down around them, would time slow down in them? Would they themselves slow down, or would their body continue working at the same speed it always did?

Please can anybody falsify this statement? “The speed of light is changing and the change is proportional to the expansion of the universe.” if the speed of light was to slow down as a consequence of the expansion of the universe, when we consider E=MC2 than the drop in energy would explain where the energy comes from to drive the expansion “DARK ENERGY” . In the distant past when the universe was half its size, consider the fabric of space time conducting light much quicker , just like vibration waves through a compressed spring would travel faster than waves through a not so compressed spring. This would also give symmetry to gravity always being attractive, gi…

Help, I need help, yes don't we all but I need your wise council. I'm writing a sci fi story(yawnnnn), I know but it's good, honest(yawnnnnnnnity yaawwwnnnnnn). Okay, I was doing fine with my theory on time travel that I invented(if suich a thing is possible) then some nasty fact based physicist came along and told me my beautiful theory was crap.... such is life. I don't agree but I'm sure he's right... anyway, can any of you erudite physicians of the mind give me info to support my theory OR a better/possible theory that isn't yet debunked, with a cyclotron preferably? MY THEORY IS : a) gigantic super collider(diameter of the USA entering parts of Ca…

Just a quick question for those who are knowledgeable in this area: in the 30+ years in it's existence, has string theory actually done anything in terms of furthering our understanding of nature? I mean, there are a bunch of pop-sci books and so-called "documentaries" that all serve to overrate the merits of the theory, claiming that this will lead to the "Theory of Everything", or answering all of those annoying unanswerable questions (e.g. why *insert pseudo-philosophical topic here*?). But, after having read all of those newer books (e.g. Elegant Universe), they don't really say anything different from what Steven Hawking wrote in "A Brief History of Time", and t…

Is space-time alone thought to have density? Would areas of space with higher gravity be considered more dense? Merged post follows: Consecutive posts mergedI guess I could ask the same question about mass as well... Is it possible that an object's (mass) density increases in areas of higher gravity? Not from the actual force of gravity on the object, but from an effect similar to red/blue shifting.

hi Im from Portugal and im just finishing my last exams from highschool in june. Im planning to go on theoretical physics. The problem is... I have been reading lots of forums abroad the internet and now i know that The best university to go depends majorly in the branch i would like to follow through. My interests are definitly teleportation of particles or time travel/time physics where should i go? what should i do? and, if i follow that area, whats the professional ways out/carreers? hope anyone can give me some answers, and excuse about my bad english,and some grammar mistakes i might have commited. Thanks in advance! Enigm4

Actually, I've found they recently discovered an insanely efficient way of making positrons... it works on pair production. Fire a high power laser (with sufficient energy photons) at a sheet of gold, and make a lot of positrons...see here "The California researchers estimate that with every shot of their laser, which fires every 30 minutes, they create about 10 billion positrons, also called anti-electrons." Then use an electromagnetic field to contain them. I don't think the gold even gets ruined by this... I think I have found a way to contain positrons after making them, see picture. No complicated penning trap electromagnets required. This could be used for a…

Are there any theories out there that relate 'time' (and maybe gravity as well) to the rate of the expansion of the universe?

I read somewhere that It was klystrons, but It lacked a description on the page and I could not find anything online. If a Klystron{Klystrons?} do indeed acclerate particles in things like the LHC, the how exactly do they work? If not, what does the job then? Thank you.

Ok tell me where I am wrong and let see how much CORRECT information I have obtained so fair. 4 forces carriers Strong - Gluon Weak - W+, W-z Z boson EM - Photon Gravity - Space? so far as we know Particles Electron Proton Neutron Muon Tau Pion Neutrino Quarks Up Down Charmed Strange top bottom All with there respective anti partcles. EM - Has electric and magnetic component corrosponding to a charge (postive or negative). The magnetic aspect comes from the moviement of charged objects or particles. Like the rotation of the earth core? something to that effect... Strong - force that holds quarks and ganis streng…

What's the story behind this discovery news article? They seem to claim that cold fusion is possible. I will make a wild guess and say that most people here would tell me the opposite. Why? What are the hurdles or snags in cold fusion? And do you think the scientists talked about in the article believe that it is possible?

energy=mass x circumfrence squared. yes ok, and the atoms and energy are the same thing? at least thats what einstein proposed, well, if we can take the energy out of an atom{i.e. atom bomb}, can we take the atom out of the energy. well, not take out, more like make out of.? if so, this can be used for alot of things, i know that this will take alot of energy, but, if we can supply it, then we can use these things on spaceships and make food and water and elements for repairs with this, and send these things to places like africa and solve world hunger by making food out energy. i know this will take alot of energy, but this is mostly future tense{hopefully neat future} a…

I was watching Stars Wars over the weekend and the death star got me thinking Could a gamma ray burst from outer space which generates about10^47 J aimed at earth destroy the planet.. I think it would be enough to at least destroy the atmosphere... any thoughts out there...

Hope that's not too provocative a title... In brief: does particle physics actually have any applications? I am a strong believer in the pursuit of knowledge for its own sake. It seems to me, particle physics - smashing atoms together at the LHC (or not as the case may be, heh) - is pretty much the ultimate realisation of this. I was wondering, does this kind of research have any applications outside of its own field? For example, relativity seems obscure to the layman, but is used in, say, GPS satellites. Cheers Kaeroll

Baryogenesis refers to the event in the early universe when the imbalance between matter and antimatter began. However, wiki puts forth no possible mechanism for such an event, and I'm curious as to how modern scientist suppose this occurred. Any ideas?