/sci/ - Science & Math

There was some recent news about successful experiments in "faster than light" information transfer via quantum entanglement.

My bullshit sense tingled, but I know nothing about physics.

Why is it bullshit?

Explain M theory using only mathematics.

Why is that masses attract other masses? Not talking about the space-time grid.

Does nature have more than four spacetime dimensions?

fucking magnets, how do they work?

OP has disappeared never to return...
>>2966566
>>2966568
>>2966575

>>2966585
You forgot to quote my question.
>>2966579

I saw some pics of black holes, and there were some of a huge black hole eating a nearby star. There was a nice shiny disc around the hole going in circles until they got sucked in and died.

And there were jets of plasma going perpendicular to the disc, upwards and downwards. WTF? It's definitively not because of gravity. Then what it is?

>>2966596
Was in the midst of writing my reply when you commented.
Or OP thinks that's too easy to answer.....

How does the CERN restrooms look?

>>2966568

Good luck OP, try /b/.

my brain is full of fuck

>>2966566
It isn't. However, it really isn't information travel either (in the strictest sense).

Dumbed Down:

Say you have a blue marble and a red marble. And you place each in one hand. You tell someone to pick a hand. He finds its the blue marble, and logically assumes that the other hand has to be the red marble (which it is).

That is pretty much entanglement. You present a "unifying concept", like each hand has a differnt marble. Then measurment of one 'hand' allows for you to know infomation about the other hand, without actually measuring. The only additional part is that you can actually choose the color of one of the marbles, hence changing the color of the marble in the other marble as well.

"That is the spooky action at a distance"

In what ways is space physical?

>>2966615
Time does not care which direction you or the light is travelling in, it still slows down. Conversely the light will always appear to travel at the speed of light, regardless of your direction, its direction or your perception of time. These troll physics questions are all the same, they make you focus on the wrong thing

>>2966568
M-theory isn't physics. It is mathematics.

>>2966575
The existance of the "mass potential" minimizes the lagragian. Hence the masses much attact other masses.

Unless you ask your question with more specifics in mind, all I can give you is that general answer. Rephrase your question if you want.

why is there a destroyer of worlds statue infront of cern.
asperger humor?

>>2966656

>M-theory isn't physics. It is mathematics.

Nope

My question is concerned with the double slit experiment that proved that observation is not the same as reality.

Have the repeated this test with other subatomic particles?

>>2966579
All evidence points to no.

>>2966604
http://en.wikipedia.org/wiki/Relativistic_jet

>>2966610
There are aot of restrooms, it is a big place. Lie most of CERN (taht region of), there are bugs fucking everywhere.

>>2966581

Actually, this question was meant seriously.

How do you calculate terminal velocity and the time taken to terminal velocity in a free falling obj?
How do you measure air resistance? In what unit? force per area?

>>2966676
From Relativistic jet:
> The mechanics behind both the creation of the jets and the composition of the jets are still a matter of much debate in the scientific community
From polar jet:
> While it is still mostly a mystery to physicists how polar jets are formed and powered...

Thanks, I guess. At least, on the bright side, I've learned how it's called, if nothing else.

>>2966666
Not OP, but I'll field this one.
http://en.wikipedia.org/wiki/Double-slit_experiment#When_observed_emission_by_emission
Clearly references protons and electrons have been tested also.

>>2966663
That is actualy in back of this little wooden bench kinda area (for eating). I think it was donated by some indian science orginzation or some shit.

I guess it is kinda funny? asperger humor? NO.
The asperger humor would be the fact that all the street signs and areas are named after scientist. Neil Bohr Rd., Einstien Blvd, Max Plank Lane. etc. I believe the little area where the "destroyer" is is Galileo Garden or some shit like that.

>>2966706
http://en.wikipedia.org/wiki/J._Robert_Oppenheimer

In case someone didn't get it.

>>2966705

Thanks man!

What is the metric of a 4-dimensional lorentian manifold with a mass which is accelerated at constant a^mu?

How do the Pauli principle works on electrons when the system is two (non interacting) atoms ?

I find it easy to visualize bent space and how it Creates the orbits of planets. But I find it really hard grasp it when one object is tiny comparable to the other object. Objects on the surface for an example.

TL:dr; How do I visulize warped space at the surface of a planet. How Is the straight path down towards the planets centre.

Thanks einy! You the shit.

furthermore:
hypotetically, can there exist a (black hole like) singularity without particles in it?
Like a moving black hole wave?

For OP only,

How do we know the age of the Universe? (serious question) Can you please tell me at least two ways that point us to the age as we know it [13.75 ± 0.11 billion]?

My physics professor who is a spokesperson for a major accelerator, had a hard time answering this question.

>>2966734
Hubble, redshift, google

>>2966698

From Relativistic jet:
>The hypothesis is that the twisting of magnetic fields in the accretion disk collimates the outflow along the rotation axis of the central object, so that when conditions are suitable, a jet will emerge from each face of the accretion disk. If the jet is oriented along the line of sight to Earth, relativistic beaming will change its apparent brightness. The mechanics behind both the creation of the jets and the composition of the jets are still a matter of much debate in the scientific community; it is hypothesized that the jets are composed of an electrically neutral mixture of electrons, positrons, and protons in some proportion.

This should be a good enough answer for you. I mean could you even follow the mechanics if they new it percisely? NO! The hypothesis is all you could even try to understand anyway.

Basically, the rotation severly warps the magnetic field. If you recall the http://en.wikipedia.org/wiki/Hairy_ball_theorem
Then it makes perfect sense how the pole (center of rotation) develops this jets.

>>2966730
Not OP but black hole is a really dense star to your question about not having particles does not make sense.

>>2966666
>dem quads

>>2966691
Srsly? Simple classical mechanics? No one? At all?

>>2966730
this made me think,
is it possible to have gravity waves moving in such a way that it interferes at 1 point in such a way that it creates a gravity well at that point, and if it is sufficiently string, a black hole? this will probably only last a very small time, but is it possible? i don't know how gravity waves interact with each other.

>>2966755

>>2966666
*quints

>>2966761
lol

>>2966734

I can tell you how to directly derive that number, if you want? Using the current theortical model. Will that do?

The model (basically GR) is the standard we use.

>>2966744
well, I'm asking if there is a singularity which doesn't come from a conventianal black hole.
"can there be constructed a singularity in (pseudo-)Riemannian geometry with a metric which fulfills the einstein equations but which isn't just what we know since 1920?"

the singularity of the big bang is a bit different than a black hole for example

>>2966691
at terminal velocity, air resistance=weight

air resistance = 0.5*projected area*drag coefficient*fluid density*velocity^2

What is the significance of the sperical harmonics?

What is the deepest property, insight or viewpoint on them that you know?
How to view them in the big picture?

>>2966773
If you could, that would be great! Is this age compatible with the big bounce theory?

>>2966691
not OP:

>How do you calculate terminal velocity and the time taken to terminal velocity in a free falling obj?
depends on a lot of factors, first in Reynolds number will tell you in what state it is (laminar or turbulent) and you have to prety much determine all the details for every shape with experiments.
then you can use a force balance with a drag force that depends on the drag coefficient to fork out the acceleration, and if it equals 0, you have terminal velocity. the drag coefficient has to be measured for each shape and a function fitted to it.

>>2966773
Basic outline, it is actually very very simple.

1) Use GR, assume http://en.wikipedia.org/wiki/Cosmological_Principle is true. This gives you
http://en.wikipedia.org/wiki/Friedmann_equations

2) Say matter = .3, cosmological constant =.7 (these are experimentally observed values). Substutie these in your free man equation.

3) Integrate freedman equation. Solve for t_0 (the time now).

4) PROFFIT!


The derivation is actually not too hard. It is given in entirty at

http://www.astro.caltech.edu/~george/ay21/readings/Ryden_IntroCosmo.pdf

pages 109-112

>>2966796
>air resistance = 0.5*projected area*drag coefficient*fluid density*velocity^2

Why the constant 0.5?
Why velocity^2 ?

What do you mean by fluid density ?

>>2966837

Air resistance increases as the obj is faster no?

Which interpretation of quantum mechanics is the most likely to be true?

>>2966906
>Air resistance increases as the obj is faster no?
for the most, yes. there may be some speeds where you get a decrease in resistance seeing as the drag coefficient decreases over a large range as speed increases, if it is decreasing faster than the speed squared, the resistance will decrease.

>>2966931
>"true"
that doesn't mean anything.
it's physics.
so none. (not OP)

>>2966829

I put the outline, as well as a very easy to follow reference here >>2966885 .

Basically using this method, the age only depends on 1) what we say the univseres is made of (which we can measure more or less). 2) Our assumtion that the univsere is more or less the same everywhere (on a very big scale). This is the cosmological principle.

Using only these two assumtion, and General relativty, you get the age of the universe is 13.5Gyrs. This is generally refered to as the "benchmark model" of cosmology.

>>2966885
KING OF SCI

>>2966885
>>2966954

>>2966730

We don't even know if the black holes we've already observed contain matter in a state that allows for the existence of particles.

>>2966995
So what would happen with those particles?

>>2966726
This question deserves an answer :)

How do I shot web? And what's it's velocity?

>>2967004

Degeneracy. Though into what we're not sure.

What is the best way to learn about physics and mathematics outwith intended university courses?

as simple as possible can you please explain electromagnetism

A rolling ball goes down a slope and up a loop, but as it goes up the loop, it's accelerating backwards while velocities are still up.
Supposedly, this means that friction is acting upwards on the loop.
What?

>>2966885
From what I am reading... it seems like it is written with the big bang theory in mind. Would the big bounce theory work to give the same result or something else?

>>2967029
Consider that same situation but on the ground... the friction is acting downwards.

It is just the same thing but inverted in your example i.e. it is all relative.

When light goes in phase it can't be detected, right? So there should be tons of this kind of light coming from the sun, yes? Is there a way to pull it out of phase and make the sun brighter, perhaps? Also, is there a way to split photons from higher energies into two photons with half as much energy?

>>2966885
Can you also point out how you found those values? I know you said they are experimentally observed values but do you have something to show how they were calculated?

>>2967045
No, it is not written with the big bang in mind. It is actually the other way around. You can actually derive the big bang (what we call the start of time) from the model if you want.

The Big bounce theory uses the exact same fundmentals, they just run shit in reverse and then fowards and then reverse, based off the componets of the univserse. The premise is exactly the same though. Start with the friedman equations, then just plug in the numbers and observe how time and space evolve. If you plug in certian numbers, time and space actually contarct, and you could get a "big bounce".

The Big bounce model says the univsere is 13.5Gyrs (same as most models) from the time of the "point of expansion". There is no start of time in most "big bounce models" . They claim time has always existed.

>>2967104
I can't tell you exactly how they are found, cause I am not an experiemntal astronomer. It is basically just "looking" with all sorts of fancy telescopes though.

Those numbers are basically the percentage of the universe that is "matter" and "dark matter". Experimentally they say our univserse is 70% dark matter and 30% matter (massive objects). Hence, .7 and .3 .

I'm sure it goes into more detail in The book, if you are really that intersted.

>>2966724
>How do the Pauli principle works on electrons when the system is two (non interacting) atoms ?

It has been bothering me for a while : how can electrons have the same energy in two atoms (and thus emitting the same light when dexcited) with Pauli ?

>>2967130
>>2967163
>>2966885
>>2966954
real science? on /sci/?

>>2966724
>>2967168
I don't understand what you are having trouble with? Clarify

>>2967163

Since some physics these days say that the universe is about 90% dark matter and others say that there might be no such thing as a dark matter in the universe.

Does this kinda make this whole age estimate not credible at all?

>>2967207

Pauli's principle states that fermions in a system can't have the same characterisitcs.
Use a system of two atoms of the same kind (non interacting, not to mess things up) and consider two corresponding electrons.
Same quantic numbers, therefore different energy.

Then how can they be emitting the same wavelength when desexcited ?

Does a freely falling charge in a constant uniform gravitational field radiate?

>>2967229
Its accelerating therefore yes ?

>>2967219
What? If the electrons belong to different atoms they most certainly doesn't have the same position space distribution, so they can absolutely have the same energy.

If you are asking why two electrons can coexist at the same energy level, that's because of the spin.

>>2967240
But maybe there is a limit speed where the energy given by the acceleration equals the one emitted.
Puzzling, because then the particle won't be accelarating anymore...

>>2967241
Then why can we use Pauli's principle in a neutron star to explain why neutrons can't disintegrate ?
Neutrons are at different places so the problem would be the same, won't it ?

>>2967241
didnt Pauli say that even if the position distribution isnt the same, it cant have the same energy?

>>2967240
>>2967244
The point of the question is to get at the equivalence principle of general relativity. Also, since acceleration is constant, the emitted energy will also be constant and there will be no speed limit because of that (if the charge radiates at all, that is).

>>2966778
yeah, 'cause black holes actually exist

Not OP but I felt like responding.

>>2967074
>>When light goes in phase it can't be detected, right? So there should be tons of this kind of light coming from the sun, yes? Is there a way to pull it out of phase and make the sun brighter, perhaps?
Photons are absorbed and emitted by our atmosphere at all times. The amount of photons in the visible spectrum that we cannot see is negligible to say the least.

>>Also, is there a way to split photons from higher energies into two photons with half as much energy?
No. When a photon comes into existence, it will have the same energy for the remainder of its existence.

troll physics question: u jell?

>>2966885
this is why i love you /sci/fags; "assume this, this, and this, none of which are true, and the answer is simple!" (too bad it's wrong)

>>2967261
No, the statement of the pauli principle is that two fermions can't be in the same state. The concept of state incorporates position, an electron at earth with energy E is most definitely described by a different state than an electron on the moon with energy E.

>>2967257
I don't really understand your point. The pauli principle in a fermion gas gives us a certain pressure, which balances against gravity in a neutron star. If the pressure due to gravity becomes to large, the neutron gas will collapse and form a black hole. But this fermi-pressure is really an effect of statistics, we have a lot of particles and comparatively few allowed states.

>>2967274
Actually if you read the assumption made... it is completely a logical thing to assume, considering our limitation and w/ good reasoning.

>>2967300
really? because it makes more sense to me that we are closer to the "middle" of the universe, as what we can see appears to be retreating from us at a pretty steady pace; also convenient in regards to gravitational time dilation theories.

or should we just assume pink unicorn horns are sharp and be done with thinking?

>>2967293

I wasn't speaking about the collapsing of the star, but about the fact that neutrons remain stable in it (even if it mean decaying time is ~30min)

The answer I was given is because there is not anymore free energy level for the protons/electrons to be (and they could not be in on already used because of Pauli principle)

>>2967212
You decide to take the opinon of a few fringe scientists, with little if no evidence, as someting of importance? Why? What is wrong with you?

Your system of logic and reasoing is very very bad.

There will always be crazies that say crazy shit. Ignore the crazies! The fact is that all the data we have about the universe suggest the big bang, and 13.5Gyrs. Sure, we could be wrong, science changes, and corrects itself. Hence the beauty of science.

You need to evalute your critical thinking skills son.

why do the spinning discs in the CD players make the flashlight stay in the same place?
http://www.youtube.com/watch?v=gdAmEEAiJWo

(the machine is imperfect, I wish NASA made a nicer one)

>>2967315
So I am wrong b/c i am open to people who don't agree with the majority? They are crazies if they disagree?

What is wrong with your thinking?

where does the energy go? hmmm??

>>2967333
heat loss.. fuck if I care about your troll shit

>>2967351
does this mean it is harder to heat a magnet with a nail away from it than a normal magnet?

>>2967325
>>2967325
It really has nothing to do with the majoirty, it has to do with the data. data => big bang, 13.5Gyrs. That's it, there really no if very litle debate on this matter.

We have nothing to suggest this shit is wrong. It could be proven wrong, if we even got more data that said so, but without that data it is illogical to assume such. You sound like a troll, or someone who really doens't understand science, I wont waste my time with you anymore.

>>2967367
http://en.wikipedia.org/wiki/Magnetic_field#Energy_stored_in_magnetic_fields

The energy is here without the magnet

>>2967351

what if the nail was close to absolute zero? How could it lose heat then. Checkmate

>>2967316
>>2967316
could someone answer this please?

>>2967378
That's the magnet who is losing energy...

Well thanks for the questions /sci/, but I gtg.
Sorry for those I didnt get around to answering, maybe later.

Also, the board has turned to mostly shit. wtf happpened?

>>2966548
Not directly a physics question but maybe you'll answer it anyway. What area of physics are you involved in? Do you feel like you have somehow a fundamentally better understanding of the universe now because of it, or are you just really good at "doing physics" ?

I ask because I'm currently pointing down the path of pure mathematics, but I'm also drawn towards physics and I don't know how to choose.

>>2967371
I understand that the data shows that. However, new questions are coming up and so it could possibly turn this all into garbage. There is data but just not enough... doesn't mean they are wrong. All ideas start small...

>>2967378
Heat = energy

Hot --> cold

PS: It helps if you think of hot/cold as kinetic energy.

>>2967400
Too many bad trolls and underageb&.
But whatever happens, Physics Guy, don't ever leave us.

For a source-free polarized medium with free space permeability, but where there is a volume density of polarization P, a single vector potential (A) may be defined such that H = j*w*eps_0*curl(A).

Express the electric field intensity E in terms of A and P (capital letters represent vectors btw)

can a reflection have a shadow

Stop trollin kikestein

>>2967407
Ok, perhaphs I am being too harsh with you. Yes, I know what you are saying. And you are correct. That is the great things about science, it is possibly falisfyable.

However, the problem is your logic is stilll pretty fail. Yes, new theories come up and replace others. That is how shit works. However, it is unreasonable to not accept current thoeries (when they work really well) cause you want a better theory.

You will never get anything accomplished and have no science or technology at all.

So, maybe new theories come up, and replace the big bang, then more theories replace those, then more theoreis replace those, adinfinimum. According to your logic, you will never believe anythign then. You are the supreme skeptic?Cause you are always waiting for a a better theory? Where does it end? when do you finally accept shit? Is there some bullshit arbritray line you made?

Even though, all the fucking thoeries produced very usuful results, explainations for shit, as well as predicted all sorts of shit, you never believe anything. You use elctricty, but dont believe in electrons, you drive a car but dont believe in thermodynamics. Do you understand your fundemental fail yet?

Additionally, FYI: Theories are seldom completely discarded, they are just "limited in there range of validity". Example, Most Big Bounce theories imply all the big bang theory, it just limits is range of validity.

>>2967400
didn't get your ass kissed enough? lol

>>2967485
oh, now u mad

>>2967402
>What area of physics are you involved in?

Experimental Particle physics at the LHC

>Do you feel like you have somehow a fundamentally better understanding of the universe now because of it

Yes, of course

>are you just really good at "doing physics" ?

Yes, I would like to think so

>I don't know how to choose

Do what makes you happy. Most particle physicst have multiple degrees (often a math degrss in there somewhere).

I know plenty of physicst that participate in the mathematics community, write actual math papers (journal articles), and go to math conferences (just like mathematicans). It ends up being easier for a physicst do to math, then for a mathematican to do physics. Only becuase of resources. (not becuase of intellegnce, in general mathetican are a little smarter then physicsts)

To be a good physicst you usually need a lab/data, these are things that you will not get unless you are a physicst. While to be a good mathematican usually requires nothing more then your sheer intellect. You can do recreational mathematics, or even do it professionally (at the level of a university) with little, if no, resources. It is damm near impossible to do university level physics research recreationally.

If you are still doing undergrad though, just double major, like most smart people.

>>2967492
I said I was being tooo harsh, and that the other anon has a good point.

How do you take that as me being mad?

What education ?

Could you please explain precession?

>>2967546
i'm trying to help you to not get trolled so easily, by trolling you so obviously, and yet, somehow, i have failed

i will now an hero, so nobody will accuse me of running off the only actual /sci/ OC contributor left standing

>>2966548
How can light have momentum but no mass?

>>2967485
Yeah of course, I am not going to believe that the age of the universe is not credible until the new dark matter theories get more data.

I was only saying that these theories do add to the skepticism and was wondering if it is evidence that nothing is really set in stone especially this age of the universe thing.

I didn't know that the 70% thing was the one with more data personally but I will take your word for it. I know it isn't exactly your field either, so I will go read that book more about the whole thing in depth.

Anyways, I will ask another question:
What percentage of physicists actually believe the whole many dimensions thing (M Theory)? I know it is not accepted by some b/c they claim it doesn't have enough data but how much do the agree on the theory?

Can you elaborate on string theory?

I understand the basic concepts but I want to learn more.

>>2967577
Thanks

Yall and your trolls, silly kids.

What exactly is spin?

Is there a smallest indivisible piece of empty space, or can you keep subdiving it forever?

>>2967535


>I know plenty of physicst that participate in the mathematics community, write actual math papers (journal articles), and go to math conferences (just like mathematicans). It ends up being easier for a physicst do to math, then for a mathematican to do physics. Only becuase of resources. (not becuase of intellegnce, in general mathetican are a little smarter then physicsts)


thats because most of the time they write papers on pure math that is directly related (or the same as) the physics they are working on...


people who work on nonlinear problems in wave mechanics and fluid dynamics (aerodynamics, water waves, stress mechanics, etc.. includes all types of engineers, physicists, and eve chemists) write papers on PDEs (which is about as wide of a subject area as you can think of)...

people who study finance write papers on discrete mathematics (there are fuckloads of Ph.D. physicists working for finance companies these days)...
its not so surprising. I think the concept of "math for maths sake" in high level professional circles is a modern concept, that wasnt even really well known until the 20th century... Things started to change around the 1850s when many of the founders of modern QM and HEP were born... though they did not begin to even start studying until the 1870s, and werent respected well enough to publish until the 1880s, and that was for the earliest.

This is not really a physics question but just a question to see if you do know about this.

The current education system is making people study hard to get money and fame (nobel prize)... in every field people are just ripping each other apart metaphorically.

Not many are interested in the subjects they work on anymore as they do it to become better than others and not for curiosity. People like Einstein are going to be lost in this struggle and be weeded out... whereas book smart people who just want fame and money will become well known physicists but never be as fruitful as geniuses.

Are you guys on top of these fields aware of this? If you are, do you guys try to do something to change this for people do want to study b/c they are curious about the world and not just for pride/money?

>>2967535
I see that you work at LHC...There was some data "leaked" about some particle (rumor that it the Higgs Bosons).

http://www.livescience.com/13853-higgs-boson-signal-lhc-cern.html

Is this credible or just a bunch of hoax? You don't have to lie about it if you can't say anything. We understand.

so when you do Raman spectroscopy, and you shoot non-selected (eg not matched to some specific Abs energy of the rovibronic manifold) laser light at a material...

what state does this energy excite the molecule (no Raman for atoms) to?


I ask because it is always presented as being a "virtual energy state"


this is non relativistic QM, not some insane theory that needs black hole event horizons... this is shit you can do in a 10 cmx10 cm box for like $500.


its the same thing for Rayleigh scattering.... Rayleigh scattering works for ANY light, not just light that is specifically tuned to the frequency of the absorptions of the molecules (or atoms) that the light travels to.


so the whole: "excite to excited vibronic manifold, decay to the ground vibrational state, fluoresce back to the ground state, or ISC to triplet(or other excited, but lower energy state) and decay back to ground state (either through spin allowed fluorescence or forbidden phosphorescence)"


that shit doesnt happen in the air in the sky. or in a Raman experiment.

1 laser of 1 frequencey works for ALL gasses. no tuning, no need for any complicated optics or electronics to shape and tune the laser output.


you can do this with a COS diode laser and the right spectrometer (which is also COS and works with USB)


you dont need to know anything about the material of interest BEFORE you do the experiment.. just calculate the difference in energy, and that TELLS you the vibrational frequency of interest.


wtf is a virtual energy state?

>>2967593

Check out the 5year results, and see the data yourself, it is pretty clear cut.

http://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy_Probe

If you are not comfortable with the 13.5Gyrs. Just change the numbers and see what you get, you will still get numbers in the Gyrs.

The lower bound that makes anysense is 9.8Gyrs. This is the time when the dark matter is equal to the matter.

If you use .9 dark, and .1, you will get a number greater the 13.5Gyrs. I think about 15~20Gyrs (not certian though).

>>2967673
Thanks !

>>2967552

>This

How did you turn up being a physicist, working at cern. What path of carrier, what nationality, what uni ?

>>2967593
>What percentage of physicists actually believe the whole many dimensions thing (M Theory)?

.01% (that may be too high though)
Generally speaking M-theory is not physics.

>I know it is not accepted by some

It is not accepetd by the overwhelming majority. It isnt even considered a proper form of science. Why would you assume it is physics? Pop-science is feeding you very shitty lies.

>>2967702

Have you actually met a few of the typical pop-sci guys? (E.g Law. Krauss; Michio; Brian Greene; Neil Tyson and so on.)

In that case, what are they like? Is Michio really that much of an idiot?

I have a possibly dumb question: There was recently some theory about gravity being a result of entropy. I think one of the examples the article had was an avalanche of snow caused by the mass receding to a state of lesser potential energy. Then again, gravity can cause atoms to clump and cause reactions (Suns), so it generates negative entropy -- Or am I getting this all wrong?

>>2967702
I don't believe in the M theory myself. I just asked that b/c Stephen Hawking seems to believe in it:
http://www.guardian.co.uk/science/2010/sep/02/stephen-hawking-big-bang-creator

So I was just wondering if he does represent the majority of physicists or if others think he is losing it too...

>>2967552
>>2967692
1)Get undergrad physics, undergrad mathematics degree

2) Get masters degree in physics

3) While pursuing doctorate, start working at LHC

4) Get doctorate, work at LHC


You choose what you will do as a "carrer path", when you are doing your masters or doctorate. You apply to universities that have the connections, resources, and programs that you are intersted in. There are dozens (at least) of US universities involved at the LHC. I picked one of those, and they started sending me to CERN during summers, then I moved permenetly once all my classes were finished. Then stayed, after I graduated.

Nationality = American

Principle of least action is what you are probably thinking of. Systems evolve in such a way that they prefer to minimize the Lagrangian. L=K-U where K is kinetic energy and U is potential

Physics Guy, if you're still there;

Why does gravity exist? (Why are smaller objects drawn to larger ones relative to distance between them). Is it just an accepted fact that it's how life works, or are there deeper(for lack of a better word) reasons. Is surface tension or heat at all a factor?

tldr: Why is there gravity?

>>2967718

Pop-scientist do not represent real scientists, or the beliefs of the scientific community in general. In general pop-scientist are werid eccentric fucks, with laughable, yet exciting ideas. The public doenst wanna see a real scientist, yall want the crazy guys who hype up nonsense and fantatsy, so it keeps your short attention.

>>2967713
Fuck no. I wouldnt want to. I would rather meet real scientist. Nobel prize winners and such, that is who real scienist seek to meet, and look up to, not shitty hawking or greene. I know tons of guys just as smart as hawking or greene, and not as fucking "out there". Most pop-scienist are nothing special.

You do particle physics - I take it your favourite scientist is Brian Cox?

>>2967821
General relaitivity explain it pretty well. Objects wil momenta or mass being space-time. Unless you give a more specific quesion, I cannot give you a more specific answer.

>>2967827
Sorry, no idea who that is.

Any thoughts about string theory? Does it compete with the TOE?

>>2967823
Cool. I thought Hawking was respected but I guess he is just another pop-scientist guy.

Can you answer this? >>2967663

>>2967842

>>2967846
He WAS respected I believe. Back when he did black hole shit.

>>2967846
He is probably the most respected pop-science guy. He actually did some good research once and was well respected, but he kinda stopped. His endorement of string shit kinda threw alot of his credibility out. String theory is really not a very popular idea in physics. Many oppose it idealogically just from principle. I mean, given enough dimensions you could fucking model anything. You keep giving yoself extra "slack" in your math, and anything is possible.

>>2967886
Everything is instantly credible with a Norman Borlaug pic

>>2967886
I agree. I am glad physicists don't like him. I felt like I was the only person who thought Hawking was turning into an idiot and M theory (and string theory) was also just bs.

Can you answer this? >>2967663

Say no if that's the case.

An airplane is on a conveyor belt which moves in the opposite direction. Can the plane take off?

>>2967663
That is a shitty april fools joke, that some retarded memebers of the generl public either "feel for", or "accidently got ahold of". It is reallly fucking funny how some sects of the general public love conspericey thoeries, and all sorts of bullshit. They gobble that shit up. Yet, they ignore real science and facts. Its also really fucking sad how their media fact-check system (as well as standards of journalism) is such shit(looking at you FAUX).

That Higgs nonsense was litteral just some post of some shitty blog, that some anon posted. Yet some media sources (FAUX) actually took it seriosuly? WTF? If I make up some bullshit here on /sci/, I wonder if they will report it? Gotta wonder.

Anyway,
A few weeks ago, Fermilab actually announced they may have found a new partcile, BEYOND THE STANDARD MODEL (not the Higgs). Somthing that is completely earth shattering, could change our view of the universe forever, a discovery way more fucking meaningful then the Higgs. They published papers, has seminars, even announced it to the media. The partcile physics community has been abuzz about this crazy new shit, trying to explain what it going on. Yet, the media ignored that, and instead decided to report the blog rumor? WTF?

>>2967982
care to provide a link with good info?

>>2967982


so you gonna answer my question bitch?

(>>2967664)

>>2967995
I did't mean to imply all news sources are shit.
Some actually did cover this story, and ignored the shitty rumor. Actually, there were a few thread on /sci/ about it too, so that makes us at least better the Faux (not really hard to beat Faux though).

>Ny times article:
http://www.nytimes.com/2011/04/06/science/06particle.html?_r=1&ref=science

>Fermilab article:
http://www.fnal.gov/pub/today/archive_2011/today11-04-07_CDFpeakresult.html

>Fermilab presentation:
http://theory.fnal.gov/jetp/talks/Viviana.pdf

>Publication:
http://arxiv.org/abs/1104.0699

There have probbaly been at least 20 additional papers, all publsihed in the last month trying to explain this shit, everyone and the fucking moms is trying to say what this could be. No concensus on what it actually is (what the new partcile is or even if it is a new partcile) has been established. We really need more data to figure this shit out, so it may take a while (6months at least).

>>2967996
Sorry I didn't get to it already. Maybe, if you ask nicely I will answer it.

>>2968091
I am well aware of that fermlab particle thing... this is not related to that question, otherwise i would have mentioned that.

I just wanted to know if it was fake or not. That's all. However, I do know about the other particle found at fermilab.

Just a general question, not trying to start a trollfest or anything but within the physics community how many people are actually religious? Or is it just something that nobody cares about even discussing when there is science to do?

To add to this >>2968165
, the fermilab thing wasn't actually a confirmed particle. It could be just some error in the data.. and so they are unsure about it.

I felt like the other higgs stuff was fake so I am glad you confirmed it.

>>2968091
>everyone and the fucking moms is trying to say what this could be.

You got any thoughts on it you'd care to share?

>>2968184
>>2968165

Yes, it could very well be an error in the data. My point was that for some reason the general public was more inclined to care and discuss a rumor, then actual science. They wanted the rumor? Kinda sickening.

Brian Greene is actually a pretty chill guy. I've had the opportunity to see him speak a couple of times and have spoken with him as well.
He's pretty up front in acknowledging that M-Theory isn't science and that it's based entirely in mathematics though he's optimistic that it will one day be testable. He's far less of a loudmouth faggot than Hawking is right now.
Personally... I'm just a lowly astrophysics undergrad and the math is way over my head but I do have a respect for what he's trying to do... Whether it proves fruitful or not. (To a limit of course...) Though he seems prepared to surrender string theory all together if results demonstrate otherwise and is concerning himself with its current unfalsifiable state, something he recognizes as a major problem.

A lot of the crazy pop /sci/ bullshit that you see on TV is actually quoted way the fuck out of context -- Kaku's a pretty cool guy as well. "Physics of the impossible" is pop /sci/ and just that. It's intended to get people interested in science and to encourage the public to fund the REAL science that you get to do down at the LHC... Show a bit of respect.

>>2968213
Well I personal knew about both. I know all that I could understand about the fermilab thing so I didn't want to ask about it. I just wanted to find about the higgs thing since that's one of the biggest things that lhc is planning to find and i wasn't 100% sure if the new leaked stuff was fake. But I understand why you get mad at stuff like that.

Btw, do you guys dislike each other since you guys compete each other (fermilab)? Or you don't care?

Also like someone else mentioned, how religious are you guys? I know you guys are more sensible than the biology department about the world around us so what do you guys believe?

Would you consider working for the government/military to serve their purposes, if it meant you got to pursue your own discoveries and research at the same time? Like if you had the chance to work on the next Manhattan project, potentially revolutionizing our understanding of the world in the process of engineering a weapon or mind control device or something like that.

Would you do it for the sake of advancing science, or would you have moral/ethical issues with the ramifications? Also moral/ethical discussion general, does that ever even crop up in particle physics?

>>2968168
>Or is it just something that nobody cares about even discussing when there is science to do?

That is the case. There are social occasions though, where that stuff is occasional brought up. Most of the physicsts I know are either athesists, pantheist, or agnostics. Atheists being the majority. It is usually assumed that all physicst are atheists, this is actually a good working assumption. It is actually kinda nice. Its like all the bullshit-needless-nonsense was already cut away, and everyone is on the same page, ready to get shit done and make the most of life.

I 'think' I know one christian physicist, but you can tell he is very ashmned of his religion, and tries not to discuss it. I know a couple of muslem physicts, they arent ashamed at all, but they still dont really talk about there shit.

I personally have nothing against religion (obviously), I doubt you would find too many physicst who do. No offense to the religious, but it is kinda just viewd as a 'childish endevor' to most physicst (at least from my experiences).

>>2968213
o damn its robin williams!

Though I do have a question, one I'm sure could easily be answered by a google search but since you're right here: What is the most commonly heard language at CERN? I'd imagine that French is common but English the lingua franca?
As well..
What nationality are you?

Is it possible that the expansion of the universe is harmonically accelerating, as in the rate of acceleration increases/decreases while the mean rate of acceleration is linearly increasing?

I have wanted to know this for years.

>>2968352
English between the scientists. Everyone speaks english, all meetings are in english, all lectures are in english, all events are in english, etc.

French, by the staff, secretaries, cafateria workers, security guards, groundskeepers, engineers, janitors, etc. Bascially, the 'help', since they are usually local.

That's not to say you dont hear french, japanses, romanian, spanish, or _random language_ from scientists. You hear plenty of languages everyday. But for all pratcicle purposes, when communitaing with people of differnt countries, or for the first time, english is used. It is the accepted formal default language for scientific business.

I'm American

>>2968386


Alright. That's what I expected.

Where I grew up in Grenoble France next to "Le Polygone Scientifique" it was the same deal -- administration and international communication in English although French was definitely the most commonly heard language. I suppose this was likely because most the scientists there were French however.

>>2968276
>Would you consider working for the government/military to serve their purposes....

No. I actually turned down several offfer to do military work with the DOD. In general the military (even there science shit) is not that good. I would have felt like I was taking a step back, not forward. They military is not known for it's intellect. I simply wouldnt work with them, becuase they are not up to my standards.

>moral/ethics of building weapons

Yes, I would be opposed to building weapons (for others). I may feel different in war time though.

>Also moral/ethical discussion general, does that ever even crop up in particle physics?

No, not really.

Why do you come here to /sci/? I am glad you are enlightening us but what's in it for you? Just happy to share your knowledge?

>>2968466
I get to brush up on shit I should already know. The more I talk about physics, the better I will become at physics. It really is very simple idea. Think of it as community serivce, that benefits us both.

Talking to yall about phyiscs, Is very different then talking to physicsts about physics.

I don't quite understand this: http://en.wikipedia.org/wiki/Bucket_argument

Could you explain in simpler terms please?

>>2968489

Here are some questions:
Who is your favorite physicist?

Do you believe in Big Bang or Big Bounce?

How many dimensions are there according to physicists that don't believe in the M theory?

Is gravity up or down? Once a physics forum explained gravity as something similar the force that pushes you back on your seat while in a car that accelerates forwards... is this wrong? Are we being pushed down b/c we can't move up as fast (like in a car)?

>>2966548

have you ever "vahoo'd" before? Or was that strictly in the movie?

What is the significance of the sperical harmonics?

What is the deepest property, insight or viewpoint on them that you know?
How to view them in the big picture?

bump

Can you please explain what a tensor is? Trying to learn GR, but I can't find a decent introduction to these things.

>>2969195
http://en.wikipedia.org/wiki/Tensor_%28intrinsic_definition%29

How does this work? Even after reading my book I am still confused.

>>2969461
I'm a lurker and even I know this. It's faraday induction.

You know, the rate of change of magnetic flux...

whats the fastest way i can learn "general physics" in one week and be able to do well on a final.. despite not knowing shit

test taking tips?.. its not like the questions are hard i just have trouble being able to work it out

Electron tunnels through a barrier and comes out on the same side with the same potential energy. I know the probability that is it there is decreased, but how the fuck is there no energy transfered while tunneling through a barrier?

PORTAL INSERTED INTO ANOTHER PORTAL. WHAT HAPPENS?

Time wiped completely, forwards and backwards or what?
Unleash unspeakable evils of another plain of reality?

>>2970034
>if they aren't too fucking retarded.
>full retard.

dear guy, I'm a physics undergrad at Reed College. Almost no one double majors here because we're assigned a lot of work (I don't think there has ever been a physics math double major at Reed).

However we have something called a math-physics "dual major" where you exchange junior lab for real analysis and abstract algebra (I have taken math through multi and linear).

Should I be a math-physics major or a physics major? Should I feel dumb for not double majoring?

>>2970212
>Should I feel dumb for not double majoring?

Yes

>>2970012
>but how the fuck is there no energy transfered while tunneling through a barrier?

Cause this is not shitty classical mechanics. You best throw out all your 'macro scale' preconcieved notions, they will not help you. It is not like the wavefucntion is a physical entity. It is not a particle that physically travels through the barrier, so stop thinking of it that way.

>>2970271
fuck you dude

>>2970271
Are photos like this of physicists posing in front of chalkboards filled with equations taken from a desire of academics to link the subject of the photo with the specific thing on the board, or is it just the sort of picture taken by an outsider who says "Hey, pose in front of all the stuff that makes you look smart"

>>2970763
That board looks somehow legit. I see a bit of radiation transition amplitudes mixed with some perturbation theory..

Does the many-worlds interpretation of quantum mechanics predict that all possible outcomes of anything with a outcome depending on the wavefunction will be handled in different universes?
Or is there a chance that some of the outcomes are not handled at all?

And when does this split of universes occur according to the many-worlds interpretation? If it's on an observation, could you define what this observation is?

So for example, if you shoot a photon in such a way that it could end up at either detector A or B, will there be at least 1 universe for each of those solutions? And when does the split occur, is it upon firing the photon, upon the paths diverging, upon detection by a detector? If detector A is a lot closer, will photons heading for B lose their wave properties when they should have hit A?

An answer would be much appreciated.

>>2970756

Don't ask a question if you're going to get butthurt about the answer, son.

How important are undergrad grades for getting into grad school?

What was the shape of the universe suggested by the microwave background radiation? A dodecahedron? What is the shape of the universe, really?

Can you post a pic of your personal library?

I'm interested in what you've red/read.

>>2971836
>>2971849
>>2971854

>Implying his last post wasn't ten hours ago

>>2971858
Ah, well spotted. Why do people revive old threads then? Why was this on the frontpage?

>>2971870

People are stupid. And, apparently, unobservant.

bump

How does the Buddhist belief in four-dimensionalism help in modern physics?

Not OP
>>2971849
Not nearly as important as quality of courses, letters of recommendation from your best-respected professors, and personal lab work. If you managed to get published (even as a collaborator) you've got a big edge. Obviously they're significant though; good fucking luck getting into MIT with a 2.9.

>>2971836
Flat-ish, or maybe saddle. Short answer is we don't really know.