Slashdot Mirror
CERN Scientists Looking for the Force
An anonymous reader writes "National Geographic has a fascinating article on the God Particle, which can help explain the Standard Model and get us closer to explain the Grand Unified Theory. The obligatory Star Wars-angle summary is even better: 'CERN's scientists, the fine people who brought us the W and Z particles, anti-hydrogen atoms and hyperlinked porn web pages, are now hard at work building the Large Hadron Collider to discover something even cooler: the Force. Yes, that Force. Or like physicists call it, the Higgs boson, a particle that carries a field which interacts with every living or inert matter.'"
"Use the Large Hadron Collider, Luke."
...but shouldn't they be focusing on something much more worthwhile?
Like a working model of a lightsabre. Now that'd be really cool...
The Mothership
Basically, no.
I like to place meaningful quotes in my sig, so people will know that I know what meaningful quotes are.
The keeps of the force will use the force to stop it form being know and the MIB, SGC, HWS, CIA, NSA, FBI, MI6, M12 and others will cover it up.
I don't believe in the God Particle. ...you knew that was coming.
It's in the Midichlorians reference.
"...and hyperlinked porn web pages, are now hard at work building the Large Hadron Collider..."
Hadron...
Dammit, too much time on Slashdot
No. According to Newton's Law of Gravitation the force of gravitation allows two particles with mass to attract one another.
This doesn't cover all particles.
The Mothership
If there is no Higgs Boson, oh well...the collider has many other uses that can help move our scientific development along.
Christ I sounded like a politician right there...but it's true.
Living With a Nerd
From a linked article:
That's the essence of experimental particle physics: You smash stuff together and see what other stuff comes out.
and you get to do it with really expensive, shiny toys :)
The Mothership
I like to place meaningful quotes in my sig, so people will know that I know what meaningful quotes are.
Photons aren't supposed to have mass (otherwise they couldn't travel at light speed), so how are they affected by gravity?
These are not the particles you are looking for.
hard at work, CERN's scientists are now
the Large Hadron Collider, they are building
brought us the W and Z particles, the fine people did
anti-hydrogen atoms and hyperlinked porn web pages, they brought us as well, they did
to discover something even cooler, they are
the Force, it is
that Force, yes, it is
carries a field, it does, the particle
interacts with every living or inert matter, it does
the Higgs boson, it is
call it so, physicists do
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
You're along the right track....sort-of.
It's a good deal above my head as an undergrad, but I do understand that the Higgs boson is somehow involved in giving rise to the nature of all other particles.
Brian Greene explains it pretty well in layman's terms in his book, The Elegant Universe.
If they are to find "Grand Unified Theory" I wander if it contains not only "The Function" that explains all interactions in universe but more importantly, why is function evaluated at all and how it is evaluated. Is it possible that any mathematical function can evaluate itself, and if not, is there any other explanation? That would be perhaps more interesting answer then The Function itself.
839*929
They're affected by curved space due to gravity.
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
Argh, don't these guys watch TV?, the entire planet will be reduced to the size of a pea once the mass of the Higgs boson is known ....
...)
(for the mods, its a reference to the scifi show Lexx
This signature was left intentionally blank.
Well, to people who think that a Higgs boson is gravity, I guess it is informative. For everyone else, it's sort of like saying "a watermelon is NOT a puppy dog".
I like to place meaningful quotes in my sig, so people will know that I know what meaningful quotes are.
I want counts for each reasearcher. How strong are they in the Higgs Boson?
Why, oh why, didn't I take the Blue Pill?
Oh dear. This is just increasing the number of people who thing that Star Trek is real. I realise that they're merely out to sell copy, but you'd hope that National Geographic would retain some sense of integrity.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
Parent pretty much sums up particle physics, and why people don't get it.
If they don't find a Higgs boson, they're still stepping into a massive new range of collision energy. I think the LHC will produce collisions with a total energy of 14TeV (I haven't read about this for a while).
This step up allows all sorts of other interesting experiments to be run too.
Not to mention, GP smells a little under-the-bridge. But so does every post related to religion on slashdot.
That description is gravity as described by Newton's universal gravitation. Under general relativity, gravity is a warping of space-time, not a force. In the various incarnations of quantum field theory, gravity is mediated by a (hypothetical) elementary particle called the graviton. It works, put simply, much like the electromagnetic field, which is mediated by virtual photons, but in this case it would be virtual gravitons.
SciAm, Discover and Alan Boyle's Cosmic Log on MSNBC have all covered CERN's history and present project(s; there's two different Higgs experiments being built), and managed to do so without the silly-assed references to God particles, The Force and Star Wars. Is it too much to hope for that /. will someday stop putting out stuff written for adolescent mentalities and tastes? Probably so, since it's getting worse instead of better.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
I could get behind that...
Understanding the scope of the problem is the first step on the path to true panic.
Sort of a meta-particle, as it were.
In Xanadu did Kubla Khan
A stately pleasure dome decree
You really can't mention porn and then expect people to read Large Hadron Collider as anything but Large Hardon Collider.
I think we should put a little flag in there with a picture of Hello Kitty on it, and make it a game. The flying politicos have to try to grab it as they go hurtling around.
The flag will be pink, naturally...
Living With a Nerd
Space isn't even a particle and doesn't have mass, so why should it curve?
I wonder, does gravity affect space or merely everything in that space? Could we tell the difference?
Because Newton wasn't quite right, and matter bends space-time which means photons do noticeably bend around really massive objects. Cool.
This is not a sig
Ah, but the Higgs boson would not exist without Alan W. Livingston (The Alan Livingst-on particle?), who was responsible for the creation of all Bozons
Oops, must've accidentally clicked the "post anonymous" checkbox, how annoying.
The spammers are cashing in on the buzz around this project: I've been getting V!@9r@ spam for "Large Hard-On Provider"
www.eFax.com are spammers
As the other poster mentioned, photons are affected by gravity in as much as they travel through a space-time that is curved by massive objects. So the path of a photon (e.g. light) can be deflected by a gravitational field.
To those who would then say "Aha! So clearly photons do interact with gravity!", it's important to note that photons may be affected by the curvature of spactime, but they don't have mass and thus don't interact gravitationally. For instance, photons cannot attract each other gravitationally (whereas matter does), and a photon won't attract matter gravitationally.
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
Yes, I know, "their" not "they're". It's friday, it's 5:30 and I have to work this weekend, so grammar nazis can all go swing.
The force was so much more in ep 4,5,6. Why did they have to screw it up with Midichlorians? It's more like an invisible link between all living and intert objects just like the summary says. How do you think Yoda lifted that rock?
I prefer the idea of smashing politicians into each other to see if the resultant collision creates an honest politician (the equivalent of antimatter).
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Unfortunately folks are mixing Newtonian and Einsteinian explanations of gravity. In Newtonian physics, the particles exert attraction on one another, in Einsteinian physics spacial geometry is curved around gravity wells (whether that's an atom, a human or a black hole), and it is that curvature that causes bodies to attract.
Cue the bowling ball on the mattress with the marble moving towards it. That's a reasonable analogy of what goes on.
Then cue quantum mechanics, which takes such a delightful model and tosses it on its head.
The world's burning. Moped Jesus spotted on I50. Details at 11.
not directly, space can "bend" and light traveling straight through curved space will curve as well. secondly, photons, the particles that light is composed of has a rest mass of zero although because light carries energy and energy has mass light also has a mass because of the energy it is carrying.
Sigs are too short to say anything truly profound so read the above post instead.
By having momentum and energy, even if they don't have rest mass, and by living in a world where, it appears, Einsteinian gravity (i.e., general relativity), where it's energy and momentum, rather than just (rest) mass, that matters, rather than Newtonian gravity.
Jumping ahead a couple centuries, Einstein's General Theory of Relativity indicates that even massless particles, e.g. photons, are affected by space-time curvature. See Gravitational Lensing.
I think you're a little confused. The large hardon collider won't work properly if you're behind it - you want the large black hole collider, next door.
which is totally what she said
...slow news day.
Zen Buddhists "knew", or rather *experienced* such things twenty five centuries ago, and they weren't first either.
But such experience is not considered a valid scientific method, so...
Not necessarily. Wait 'til you cut your puppy open and you'll be glad you did.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Does anyone want to collide into my large hadron?
The large hardon collider
So that's why the Web (another CERN invention) is used to collect pr0n!!!!
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
The most incredible thing anyone could hope for is that the higgs boson isn't there.
No higgs boson would be utterly incredible.
No higgs boson would be like the sudden realization that there's no aether. When we had to swallow that one, the result was special relativity and the whole world changed.
After all, the whole concept of the higgs is a scalar field permeating the whole universe giving things inertial mass. That field quantizes into these little happy things called Higgs Bosons, which, if Higgs was right, ought to be producible like any other particle by pumping enough energy into a small enough space enough times for the odds to be in the experimenter's favor. The fact that you ought to be able to make a higgs boson (and, to be cruely explicit, watch it decay in a rather unique way that leaves little doubt that what decayed was a higgs) is a prediction that's almost something of a side-effect of the existence of the higgs.
Higgs seems a lot like the logic of aether applied to the problem of inertia, at a high level. Aether, if you recall, was some stuff permeating the universe through which light travels as waves, giving it its observed properties.
Higgs plugs a hole in the standard model, that of inertia, that happens to also come from the same fundamental something (mass) that results in gravity. Higgs lets us just sort of ignore the whole inertial mass = gravitational mass thing and therefore not worry about annoying things like relativistic quantum gravity, which is enough to give anyone enough of a headache to be unable to apply enough duct tape to make it work (renormalize the infinities away). It also doesn't hurt that the energy levels we're playing with still leave gravity a pretty meaningless force, in terms of the magnitude of its effect on the actual behavior of particles.
If higgs isn't there, there's a lot of work to do in the standard model again. There would be answers we don't have, and some of those answers could very well go to the very nature of inertia and gravity itself. That would mean physicists can stop playing with toy models of 11-dimensional energy spaghetti branes (I'm not a fan of M theory just yet) and get back to some real work that's testable in the real world with a real supercollider, which we just happen to have build, called the Large Hadron Collider.
Right now, to make physicists deal with the holes in the standard model, without going straight to energy spaghetti branes, one has to bring up something annoying like neutrino oscillation. No higgs would be a field day.
No higgs would make the LHC immediately worth every cent, and woth every politician some physicist had to give head to to make it a funded reality.
I hope the Higgs boson isn't real.
No experiment that tests a solid theory is a waste. If there's no Higgs Boson, there is no Higgs Boson. But then we have proof that there is none.
We're currently in the "godlike state". We believe there is one. We have some pointers leading us to believe there is one, just like the humans of all times had pointers leading them to think there is a God (or Gods, depending on your faith). The difference is, science has the means to verify or falsify its theories. Whether you can ever proof that there is a God or there is none, well, kinda hard to say. God doesn't offer a test for his existance, so you have to stay in your state of belief.
Science offers you a way to test its theories. You might not be able yet to test them because you need tools that cannot be built yet, but once you build them (and they now did), you have a test, and you can find out whether the theory holds its water or whether you can toss it out and work up something else.
That is what science is about.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Photons do attract matter gravitationally. It causes the perihelion shift of Mercury, which is one of the tests that lead to wide acceptance of general relativity.
Under general relativity, "spacetime curvature" replaces the "force of gravity" as a paradigm. Photons make their own little divots in spacetime in accordance with the mass equivalence of E=mc^2.
Even if it doesn't, I'd consider the experiment a success.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
But this all has nothing to do with Gravity in the sense of "things attracting each other due to their mass", or rather "mass curving space-time". The Standard Model does not incorporate Gravity in the picture (that's why it's called the Standard Model of Particle Physics, not Physics as a whole). The theory for this force is (still!) called "General Relativity". Despite a lot of really intelligent people (no self-compliments here, I have stopped working in the field as I felt way too stupid for it) trying really hard, we still don't have a generally accepted theory for how Gravity and the other, (quantum) theories can be combined in a principled manner. CERN might help a lot with this but, ultimately, we might have to wait till the big crunch, if it ever comes, to see how all those fields really unite.
But really people, why do we need Star Wars to make this sound cool? This is an amazing universe of ours. It doesn't need George Lucas to make Light and Magic.
I know we shouldn't rely on /. for physics advice, but last weekend, on the advice of a misguided commenter, I kicked a deuterium atom down the linear accelerator in my backyard the wrong way, and hoo boy! I won't be hearing the last of that one for awhile.
Your mind is clear / The things that you fear / Will fade with how much you / Believe what you hear
"For instance, photons cannot attract each other gravitationally (whereas matter does), and a photon won't attract matter gravitationally." What makes you so sure? A photon might attract another photon gravitationally, but the force might be so small compared to other factors. It is ignorant to say with 100% certainty what does and doesn't happen when the top scientists are still trying to figure this stuff out.
Well, it's dyslexic... Or is that a simple misspelling, different from dyslexia?
Maybe they're thinking... "May the FARCE be WITH you"?
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
There, fixed it.
If you disagree with me on social issues, then it's pretty clear that you are a narrow-minded bigot.
Curved spacetime is a mathematical model we use to describe the motion of matter in a gravitational field, it doesn't mean space is physically curved. "Spacetime" doesn't really exist, it's an abstract mathematical concept that combines physical space with the fourth time dimension and that is what physicists use to model gravitational effects.
That's why physicists are so keen on finding a so called "God Particle", because gravity still can't be explained. We can model its effects, but since space doesn't curve some other mechanism must be at work to transfer gravitational force between objects.
IANAP, so if there are any real physicists out there correct me if I'm wrong.
Murphey's fighting Occam, and we're in the stands.
Photons aren't supposed to have mass
Peasant at witch trial: "What about really *big* photons?"
I've never understood something about the Higgs boson. It is supposed to give the massive bosons their mass, right? And yet, at the same time, it is itself supposed to be a massive boson, right? So, where does the Higgs' mass come from? Does every Higgs boson have an infinite trail of other Higgs tagging along behind it?
Ah, the dangers of getting all of your information from Science News. Mod me "idiot", but I'd like someone to explain this to me.
Tomato wedge sperm darts that are Republican.
Not on a Tempurpedic matress. Maybe that's why NASA uses it, it defies the laws of gravity!
As our way of thanking you for your positive contributions to Slashdot, you are eligible to disable Slashdot 2.0.
Get off the vent or I'll have you bent.
The effect of this curving is what we call gravity.
So is this the stuff that is being curved by gravity? Is the Higgs Bosun what "the fabric of space" is made of? These are honest questions, IANAPhysicist.
We are all just people.
All matter is made from the same fundamental particles whether it's "living" or "inert". That is until we discover the lifeform field they use on Star Trek.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
You beat me to it.
First thing I thought of was that commercial where the person is jumping on one end of the mattress and the full glass of wine on the other end.
Newton would be amazed.
Gallagher sighs in relief.
Er, photon has sufficient momentum to kick other things around. Normally, momentum is given by p = gamma * m * v (gamma = 1 for v much less than c), but for particles with m = 0, this is wrong and momentum is now given by p = E / c (where E, for photons, is given by h*f).
Unless you are going to invoke "relativistic mass" (fewer and fewer physicists use this term—mainly because a relativistic mass is the same damned thing as relativistic energy, given the correspondence between mass and energy), photon has no mass.
Nevertheless, my sibling posters are right, and the source of gravity (the source term in the Einstein equations, analogous to the electric charges in Maxwell's equations) is the stress-energy tensor (not simply rest mass of particles) and photons do contribute to that.
Not quite, he does raise the valid question of why spacetime curves, something which I've never seen answered anywhere. It can't be gravity causing the curve, as gravity is the curve, so what causes it is a good question. Obviously the answer is mass, but why and how that mass curves spacetime is still a good question...
There are two kinds of fool One says 'This is old therefore good' Another says 'This is new therefore better'- Dean Ing
Funny, I never found anything about the guy who coined the term "God Particle" being a theist. A top physicist, maybe. Nobel prize winner? No doubt. But a theist?
No, snarky theists are too busy yelling at snarky atheists... who are busy yelling at snarky theists...
No need for religious discussion here.
Don't tell me to get a life. I'm a gamer; I have LOTS of lives!
When I was in high school I read the book "The God Particle" by Leon Letterman (This is a really good book). I was wondering if the he was the first person to call the higgs boson the "god particle".
> the fine people who brought us the W and Z particles
Third Sunday of every month, April through October, is the M.I.T. Swapmeet, a flea market for computer/audio/ham, etc.
To get to the bathrooms, you walk right past the "J" building, as long as we're talking about "W" and "Z".
The living have better things to do than to continue hating the dead.
Are photons ever at rest? If so, can their rest mass be measured? Is there an indirect way to confirm that photon rest mass is zero? Or is this an untested (and largely theoretical) prediction of relativity?
Photons have zero rest mass, if they stopped moving they would have no mass, but as particles travel faster they gain mass via our favorite equation E=mc2. So Photons can be considered as having a mass as they have energy. That and the curved space time thing stated later, that works too. The higgs boson does not create gravity, it creates mass. The higgs field is the field was created to explain where where mass comes from, it's the higgs field interacting with matter. The higgs boson would be the particle associated with that field similar to the way the photon is the particle associated with the electromagnetic field. Gravity affects particles with mass so the higgs boson is related to gravity but no nearly as directly as the article implies. The graviton is the particle of gravity, theoretically that is as it has never been seen. For a good demonstration of how gravity works try throwing heavy breakable things off the roof and put the video on YouTube.
So basically, gravity?
No, the Higgs is basically a binding energy. Effectively most particles stick to the Higgs field and some are more sticky (higher mass) than others. Obviously the more you stick the harder it is to move yourself to somewhere else and this is what we perceive as mass for fundamental particles. (Note: most of the mass of normal matter has nothing at all to do with the Higgs!).
The particle physics view of gravity is a force which couples to the energy (technically the 4-momentum) of a particle, so any particle with energy will feel it. Since 'mass' is simply the energy of a particle at rest and is typically far greater than the kinetic energy (for most particles) this is why Newton came to the conclusion that only objects will mass feel gravity. However, in reality, any particle with energy will feel gravity.
Written nicely in an entertaining way for the layman such as myself.
I couldn't help noticing this statement though :
"He has long, gray hair and a long, white beard and, with all due respect, looks as if he belongs on a mountaintop in Tibet."
Those physical features are notably absent from the stereotypical mountain top Tibetan dweller - ie the Tibetan monk. Ah, using Google images shows a couple of people with long beards, but not typical, judging from the results.
My guess is that he's talking about the Unix lab named "Tibet" at Berkeley University where you'll undoubtedly find many such specimens.
Yes, I made that up - I've no idea if there's a Unix lab named "Tibet" at Berkeley.
Max.
Unless you are going to invoke "relativistic mass" (fewer and fewer physicists use this term--mainly because a relativistic mass is the same damned thing as relativistic energy, given the correspondence between mass and energy)
Actually the reason physicists don't use the term is that, at best, it is misleading and at a fundamental level is simply wrong. Mass is a Lorentz invariant: it does not change no matter HOW fast you are going. Einstein himself knew this and advised against referring to it as such. Despite this many undergrad text books irritatingly refer to it and then tell you not to use it. Which is like giving a sweet to a kid and then telling them not to eat it!
This is incorrect as stated. Photons don't have rest mass, but they DO have energy and momentum. It is the energy and momentum which couple to gravity, so that photons do interact gravitationally.
A good reference is here:
http://math.ucr.edu/home/baez/physics/Relativity/SR/light_mass.html
I understand this when it comes to stars and planets. What I don't understand about the curvature of space is how it makes my pencil roll off my desk and fall on the floor.
And if you can't ask this on Slashdot, where can you ask it?
What if I do the same thing, and I do get different results?
...but shouldn't they be focusing on something much more worthwhile? Like a working model of a lightsabre. Now that'd be really cool...
Hey - we are still working on your flying car. These things take time!!
How strong are they in the Higgs Boson?
:-)
Well, according to this one's wife, far too strong...at least she's always telling me I need to lose some mass!
To those who would then say "Aha! So clearly photons do interact with gravity!", it's important to note that photons may be affected by the curvature of spactime, but they don't have mass and thus don't interact gravitationally. For instance, photons cannot attract each other gravitationally (whereas matter does), and a photon won't attract matter gravitationally.
Nope. In general relativity, the curvature of spacetime, as measured by the Einstein tensor, is related to the stress-energy tensor, T. The T00 component of the stress-energy tensor is a mass-energy density. Mass and energy are equivalent in relativity, E=mc2. So a photon with energy E creates the same gravitational field as a material particle of mass E/c2. If it worked the way you're suggesting, with matter attracting photons but photons not attracting matter, it would violate conservation of momentum.
Find free books.
I've never understood something about the Higgs boson. It is supposed to give the massive bosons their mass, right? And yet, at the same time, it is itself supposed to be a massive boson, right?
Yes that is correct, the Higgs boson gives itself mass. If you use John Ellis' example of the Higgs field being like mud and the more the mud sticks to an object the heavier, and harder, to move it becomes. Well imagine you try to move a lump of mud. Mud sticks to mud so even just moving a lump of mud will be hard. This is what the Higgs boson is, metaphorically speaking.
Ok. Considering a curvature in spacetime is just a convienience. It is useful to construct field theories because you don't have to worry about the time it takes energy to propagate. You just calculate the field at every point and at any point in time. Then you can ignore the particles that created the field and just consider what happens locally to determine the motion of your particle. In other words, the field is just a construction of a differential (as opposed to integral) form of the force equation.
That being said, photons are most definitely affected by gravity. Gravitational fields are created and interact with energy. Thus photons have a gravitational field and attract each other gravitationally (at least theorically, because the induced gravitional field is both incredibly small and utterly dwarfed by the electromagnetic interation of the photon so we haven't been able to measure it yet). Energy is equivalent to mass (think E=mc^2). It is true that photons have no rest mass, but they do have an effective mass, seeing how they are energy carriers. Electrons have a gravitational field. Electric fields have a gravitational field. Even gravity induces a gravitational field (the self-interaction effect, AKA inertia).
ANYTHING that is deflected by a gravitational field's curved spacetime is by definition interacting with gravity. Curved spacetime IS gravity, not just an effect of it. If two objects don't attract each other gravitationally, then they wouldn't be deflected by a gravitational field. Think neutrons in an electromagnetic field. They have no electric attraction (to first order anyway) and they are, for exactly the same reason, unaffected by a magnetic or electric field (again to first order).
... is the most excellent euphemistic allusion to a metaphor that I've seen in a while.
OK, serious physics question to follow up.
Photons are affected by gravity (they follow the curvature of space caused by massive objects). But, they don't "cause" gravity, because they do not attract other objects. My understanding is that gravity is relational, which is to say, objects exert a "pull" on each other proportional to their mass. So... how can photons be pulled without also pulling? (I'm going on the assumption their pull is exactly zero, and not just infitessimally small.)
Follow-up: does this have to do with the curvature of space being a mental model, and not a literal fact?
What if I do the same thing, and I do get different results?
I browse with a +6 bias on troll (for the comedy), so your comment was near the top :)
About a year ago I was lucky enough to attend an informal talk given by Dr Helen Heath of Bristol University, who is involved in the LHC project. At the talk, somebody asked pretty much the same question; what if it finds nothing? Isn't it an awful waste of money that could be spent on $GOOD_CAUSE?
The answer was this: While it certainly is an expensive great big hole in the ground, the project has been funded by taxes on European citizens, and there's quite a lot of them. The grand total came out at something like 2 pounds sterling (~$4) per taxpayer. It has already advanced our technology to the point where pretty much anybody would be happy with the cost.
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
Well, isn't that the question that's asked at the next stage? First, question "what's going on" (aka "what is it") asked. And then the question "what makes it come to be" is asked. I am not a physicist, so I have to ask are we done with "what's going on", yet? Otherwise, "why is it going on" is probably premature.
Any guest worker system is indistinguishable from indentured servitude.
First IAAP (just not a PhD Physicist, so if that is your definition of a real Physicist, well then I guess I don't qualify).
Secondly, it is not necessarily true to say Space doesn't curve. We are three-dimensional beings and thus cannot perceive anything in the fourth dimension. That is not to say that space-time is a physical dimension. It is a handy mathematical model which may or may not have an actual physical representation. The simple fact is, that if there is a fourth physical dimension to space, and there are many who believe there may be, and it doesn't violate any laws, so it is possible. Thus it is possible that Space is truly curved and we in like manner to Flatlanders cannot directly perceive higher dimensions. So the answer, as in many advanced Physics problems is that we really just don't know whether Space is curved or not, although you'll get all kinds of science speak that makes you think we do know.
Lastly, it is common to refer to space as curved when dealing with many problems, and there are real reasons to consider the possiblility that space is truly curved, due to the properties of space around massively heavy objects, such as blackholes and our own Sun, which is massive enough to "bend" light. Or perhaps space-time is curved by the mass of the Sun.
Your pencil doesn't move, everything else does. /itsallrelative
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Thank you (and the other posters) for the correction. I clearly didn't think about that one for long enough.
"To those don't understand physics: please stay off physics-related discussions"
Discussion eliviates the symptoms of ignorance. If you have nothing to learn yourself, why are you here?
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
I am going to predict here that the Higgs boson will not be found. It doesn't exist.
Nope, don't have data to back up my theory, but I'm sticking with it.
</useless opinion>
Photons aren't supposed to have mass
No, photons don't have rest mass -- but then, they're never at rest. While they're moving, they have energy, and therefore mass (just not very much).
-- Alastair
No, the spacetime curve occurs first. Sometimes matter (which has mass) collects in these curved spacetime pockets. Now, astronomers have determined that there's more gravity out there than can be accounted for by observable matter, so they invented "dark matter". Really it's just pockets of curved spacetime that haven't collected enough matter to be noticeable.
As for why it's curved in the first place..well, why wouldn't it be? Why would the flatness of spacetime be any more uniform than the big-bang ~3K background radiation is?
(And yes, I just made all this stuff up, but it wouldn't surprise me if someone else has already suggested it.)
-- Alastair
Bad phrasing on my part: I should have said "to those who don't understand physics: don't presume to teach it".
Er, photon has sufficient momentum to kick other things around. Normally, momentum is given by p = gamma * m * v (gamma = 1 for v much less than c), but for particles with m = 0, this is wrong and momentum is now given by p = E / c (where E, for photons, is given by h*f).
This has been a really interesting discussion. Not nitpicking, just asking for clarification. Isn't momentum consistent between m > 0 and m = 0, as long as you always put it in terms of E?
E = mc^2
m = E/c^2
P = gamma * m * v
P = gamma * E/c^2 * v
(since for a photon, v = c)
P = gamma * E/c^2 * c
P = gamma * E/c
As long as gamma is 1, seems equivalent. I know you said gamma approaches 1 as v approaches 0, and photons are v = c. Does this mean gamma approaching 1 is also a factor of rest mass (i.e., if you have none, it's always 1?)
The large hardon is looking for Higg's bosoms? I can relate to that.
~ I am logged on, therefore I am.
Now that I can agree with. :)
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
There are acceptible curves of spacetime in the absence of matter, and they are called "gravity waves". Dark matter is just matter that doesn't interact with photons.
Please, for the good of Humanity, vote Obama.
Sounds a lot like frog baseball.
I swear to God...I swear to God! That is NOT how you treat your human!
Photons don't have rest mass. Of course, they don't rest, either. As a travelling photon has energy, it also has mass.
I never liked the bowling ball on the mattress analogy because actual gravity is needed to make the bowling ball move, so the analogy is muddled. Is there another analogy that would work without the use of actual gravity?
LS
There is a fine line between being a cultivated citizen and being someone else's crop. - A. J. Patrick Liszkie
The average taxpayer gets a lot of benefit per tax dollar spent on pure research. While it may seem our fancy-ass supercolliders cost millions and millions of dollars (they do!), there just really isn't that much federal funding spent on pure research... relative to the rest of the federal budget!
You wanna knock off the fat jokes!
My other car is a 1984 Nark Avenger.
A mastery of the force is required to responsably and effectively handle a lightsaber. We need the force first so we can use our lightsabers to their full potential.
Uh-huh thanks for that. I finally grok what all the fuss is about the Higgs from your analogy of the Higgs to the gravity field and the photon to the electromagnetic field. Just because we don't see Higgs running about all over the place on earth doesn't mean that there isn't a gravitational field. Just like if we looked inside a Faraday cage and saw no photons doesn't mean that there isn't an electromagnetic field to describe.
:=)
Another thought is, does this mean that there is a zoo of Higgs like things and is there an analogy to the kinds of things we have discovered about the electromagnetic field. Like the electron has charge and we have electrostatic attraction, atoms have magnetic (moments?) and forces between them. So would the zoo of Higgs like entities express similar disparate behaviors with a root in the mechanisms of the gravitational field? If we look at large scale things in the universe like galactic clusters and decide that they have 'dark matter' expressing additional mass effects through the lensing of quasars, does that mean that the gravitational fields equivalent of 'magnetism' for example only shows up on that large scale - which would explain how tough it is for us to do experiments and play with the gravitational fields inner workings down here on earth.
Given all this speculative rambling I'm now very interested in what could be learned from the Higgs if it is found by the LHC.
Mind you as Douglas Adams said 'Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, well that's just peanuts to space."
I make it about 10 to the power of 60 between vacuum fluctuations and the observable universe and if the multi-universe view is right, to accommodate all the different choices of the basic physical constants, there's another 10 to the power of 500 on top of that. Its going to take quite a bit of computing power to work out the details of 10 to the power 500 different universes each with a volume containing things over a range of scales of 10 to the 60. Looks like we need a bit more than 'Deep Thought' to do this calculation. I dont think even IBM is going to build a computer significantly bigger than the size of our observable universe any time soon. Mind you theres still a passable living to be made appearing on tv chat shows talking about how difficult is is answering the question of 'what is the answer to life the universe and everything'.
As an aside, the physicists say that many of the universes in the multi-universe have bad choices for the physical constants that would make life and therefore intelligence like ours very unlikely. This neatly does away with the anthropic principle for one thing, but it also raises the intriguing idea that there might be universes with far better choices of the physical constants than ours that give rise to something spectacularly more competent than carbon based lifeforms about to extinguish themselves with the greenhouse effect. (SETI is wasting its time looking for carbon based lifeforms, they all die out spectacularly quickly in a hot Venusian fog).
Cosmology has to be just THE most fascinating subject going. Of course we shouldn't get too worried about all this stuff, the answer as Douglas pointed out is quite simple 'keep on banging those rocks together'
http://dingo.care2.com/cards/flash/5409/galaxy.swf
Facts are history now plebs have politics for religion on social media.
It doesn't. Curved space is a perfect explanation for why things moving in a straight line curve through space, aka planets, stars, light, etc. But nobody is sure why the gravity attracts to objects together in the first place. The theoretical graviton is supposed to transfer force in the same way that the other forces are transmitted but none has been seen because the energies required are phenomenal. Phenomenal as in about a billion times what the LHC can produce. Gravitons - in theory again - act at Plank lengths (10-33 cm) which is why its hard to test.
Nobody was sure why electromagnetism produced electricity for a while either even though Faraday had proven the relationship through observation. This had to wait for relativity and the concept of electrons to explain. Magnetism is caused by the time dilation of electrons as they travel down the wire - yes its a relevalistic effect of the transmission of electricity.
Gravity is not cracked yet.
We do not inherit the Earth from our parents. We borrow it from our children.
OMG a linear accelerator, dude that is so off topic in a thread about the Large Hadron Collider!
Apocalypse Cancelled, Sorry, No Ticket Refunds
"Use the Force!" does sound much better than "Use the Higgs boson!" though. Although, surprisingly, slightly less geeky.
Yeah, I had a sig once; I got bored of it.
The first thread here devolve into a discussion of the "large hard on collider", and you want the editors to stop catering for adolescent mentalities?
/. to do the same. Quite the opposite, it is argument that that market is already well covered, and /. should continue to do what it does best.
Being professional means knowing your audience.
And listing four other fora that does avoid pop culture references is not an argument for
I've been wondering about the same thing, particularly when it comes to the marbles-on-a-rubber-sheet analogy. The sheet is obviously curved because our familiar Newtonian gravity pulls the ball/marble downwards. But that curvature then becomes Einsteinian gravity. So the analogy is a prime example of circular reasoning.
A somewhat related issue is, why is the speed of light constant? Special relativity seems merely an observation of how the universe works, not a particular insight as it doesn't explain the basic premise.
Escher was the first MC and Giger invented the HR department.
I lolled :)
As I understand it, the Higgs field is what gives matter inertial mass. In some interpretations you can twist that around to be the "fabric of space."
If they don't find the Higgs, and the LHC is capable of exploring the region where the lightest Higgs is supposed to be, then the standard model needs revision. In many ways that's MORE exciting than if the LHC finds the Higgs and just confirms what we already think we know.
In his book Lederman estimates that a third of the world's GNP is somehow related to quantum mechanics. Seems a pretty good return on investment so far.
Stochastic electrodynamics, also known as Planck's second theory, is gaining ground, and even Einstein duplicated everything in classical dynamics. The Higgs isn't a 'god particle' it is a fudge factor particle, just like dark matter and dark energy. Epicycles upon epicycles.
A somewhat related issue is, why is the speed of light constant? Special relativity seems merely an observation of how the universe works, not a particular insight as it doesn't explain the basic premise. Science never answers why, at best it's some result that falls out of another equation because of even more fundamental properties of the universe. Even if we found the theory of everything and it explained all the forces and gravity and lightspeed and whatnot, it's by no means certain that it's the only possible solution. Like in geometry we have euclidian, elliptic and hyperbolic geometry and they're all self-consistant. And if you ask why our universe is the way it is, the answer that "it's the 3rd solution to the hypersuperstringball-theory of everything" is really no more meaningful than it is today. No matter how well we model it the universe simply is, the whys are left to philsophers and the religious.
Live today, because you never know what tomorrow brings
Since you seem to know a little about it - how does the Higg's model explain the fact that gravitational mass == inertial mass ? Is there some link between the Higgs particle and the graviton ?
What is also often forgotten in this discussion is that as long as the LHC works at all it will get us at least one huge step forward in particle physics. It is poised to reveal which of the competing theories of the day is right, but if none of them are right (i.e., no Higgs particle, no extra dimensions, no black holes), that would be the biggest surprise of all - The physicists would have to go back to the drawing board and come up with completely different theories.
Newton kept absolute time separate from absolute space. Einstein allowed time to mix with space for inertial observers with special relativity. In 1915, he opened the door for time to mix with space in any situation using general relativity. Unfortunately, the math is too hard to apply.
I do all my physics with quaternions, a kind of 4D math designed to let time play with space. The smallest act of physics involves time and space playing together. To have time play with space quickly becomes confusing, but that is part of the fun. I have developed software to do this sort of thing using the command line at http://quaternions.sourceforge.net/
In a unified field theory, mass breaks the gauge symmetry EM, so no Higgs mechanism is needed.
Doug
Working on new views of old physics at http://VisualPhysics.org
LOL
Do you notice the tag here is "Large Hard-on Collider" instead of "large HADRON collider"? This is my favorite malapropism. I have a website devoted to tracking the mistake at http://www.largehardoncollider.com/
And what other answer would you expect from her. Nothing like blithely taking four bucks from each taxpayer to satisfy your personal curiosity and then claiming they'd be satisfied with dubious technological advances.
Deus est fatalis
- gamma( = 1/sqrt(1 - v^2/c^2)) does not depend on mass, so if you define it as 1 where v = c, it's rather arbitrary (as v -> c, gamma approaches infinity, so it's not a "removable discontinuity").
- When you write E = mc^2, you are talking about a particle's rest energy. In fact, E = gamma * m * c^2 (and, of course, if the particle is at rest, gamma = 1).
....
Fixing above problems, this is as far as I can take (... at least from my limited knowledge of undergraduate special relativity): If you write p = E/c (which is certainly the case for photons and all (so far undiscovered) massless particles), then for massive particles, it works out as:using E = gamma * m * c^2, with gamma = 1/sqrt(1 - v^2/c^2) (this is the correct formula for particles that are not at rest; E = mc^2 only gives the "rest energy"), we get:
p = gamma * m * c^2 / c = gamma * m * c
But of course, the correct formula is p = gamma * m * v, so it's not right. I suppose you could "define" momentum as p = E * (v/c^2)
I personally don't see anything wrong with having two different formulas for massive case (p = gamma * m * v) and the massless case (p = E/c), as these are fundamentally different cases (see: ongoing question of neutrino mass