/sci/ - Science & Math

>trollface on

why do things exert gravity on other things?

How do stars burn without air in space ?

why is blue??

If you have a box with a light in, with a mass known to very high accuracy, and you open the shutter for a length of time which can be described very accurately, and this box was in an accurately characterized gravitational field, on a body orbiting a second, more massive body, and you were to know the amount of photons that leave the box in the given time interval, then who was phone?

If the time-independent part of the wave equation is real, does this mean that the mean momentum is always zero?

Why dont satellites crash unto the planter ( example: the moon). I was told they are constantly falling, but why this way, why not just head straight for the planter

If you spill liquid nitrogen, the droplets move around and their shape oscillates. Why?

why can't I get laid?

If I put quantized mass/energy objects into your mom's double openings at high speed, does it produce an observable interference pattern?

http://xkcd.com/

Explain.

>>1865803

In the most general sense, it is because it miminimzes the "action" of the universe. You really need to define the context of "why", for me to give you any more detailed definition.

>>1865810
What wave eq are you refering to?

The general mathematical def, the QM def, the classical def?

Without anyother restrictions?
In that case, the answer in no.

>>1865808
I was phone....lol

>>1865819
http://en.wikipedia.org/wiki/Leidenfrost_effect

>>1865801
Explain quarks

how much energy is lost when light is passed through a polarizer?

>>1865846
What exactly do you want to know about "quarks"?

>>1865850
what kinda polarizer?

>>1865856
the interactions between them, should have specified.

Why can a plane fly upside down?

>>1865865
The Basics:

Quantum Chromodynamics is the study of the the "color force", the primary force in quarks-quarks ineractions.

The actual "force carrier" or "interaction particle" for the "color" force is the gluon.....ie....quarks interact through gluons.

The math that descibes the interactions is group theory, the group is called SU(3) (special unitary group of three dimensions). The neat thing about the color force, is that it also allows gluon-gluon interactions (as opposed to SU(2) with descirbes the electroweak force, which doenst allow for photon-photon interactions).

The fact that gluons interact with eacth other leads to another important property, "confinment". "Confinment" is the fact that you cannot isolate quarks or gluons.

Any more specific question?

>>1865864
the normal kind

>>1865908
There is no "normal" kind.
There are tons of differnt polarizers.

Absorptive polarizers
Beam-splitting polarizers
Reflection polarizers
Birefringent polarizers
Thin film polarizers
polarizing filters

Just to name a few

I've got a hard one for you.
So...why is the phase velocity of light in gaseous Caesium-137 faster than light in the vacuum?
Asked my professor in quantum mechanics today and he had no fucking idea.

itt somebody found out wikipedia

do photons interact gravitationally?

>>1865927

an ideal absorptive polarizer

What created the big bang? The created the thing that created the big bang? What created the thing that created the thing that created the big bang? Everything has to have a beginning but if so what created that beginning? Why does the universe not make sense?

>>1865959
They can be influenced by the curvature of space time (which is esentally gravity), this is strictly a "geometric influence" though

>>1865987

Some scientist believe that the Multi-verse collapses on itself and then re-inflates but im not a scifag soo i cant explain my work

>>1865936

Through quantum tunneling in a wave guides.
This really is nothing special though, plenty of stuff has phase velocity greater then c (all matter waves for example). This doesnt actually break or change any known physics laws, as the actual "velocity" (velocity of information transport) isnt greater then c, just the phase velocity (velocity of the front of the wave).

I demand we build a gluon accelerator. Make it so, Physics Guy.

>>1865987

Your question doesnt make any sense at all. You seem to be very confused regarding what happened in the "big bang". The time evolution process was actually a result of the big bang, meaning there was no such thing as "time" before the bang. You cannot ask what happened before the big bang, as there was no "before". I know it may be a hard thing for you to understand, you will probably need to study more physics for you to understand it.

Is the universe deterministic? If yes, how do we know? If no, how do we know? Would a probabilistic universe involve true randomness and are quantum effects applicable to larger scales (eg: randomness on a quantum level might be true while larger scale objects still behave in a deterministic manner)?

>>1865871
>>1865831
Yes, why?

>>1866068

Yes, the universe is "globally" deterministic. Ie, if I had all data (from the whole universe) at any given point in time, I could calculate the complete time evolution of the universe.

The universe if locally "probabilistic", ie if I try and isolate any section of the universe, and am given all the data about it, I will not be able to make any kind of determinstic time evolution of that section (only a probabilistic one).

We know this through advanced mathematics and physics. If you are interested in this sort of thing, a good place to start your understanding is the work of John Bell. Some of his stuff should be easy for the physics novice to understand, although most of his work will require you to already know a good amount of physics.

Any thing more specific?

Are room temperature superconductors possible to exist in theory? If so why? If not prove.

>>1866000
what year are you on undergraduate school?

>>1866090
Not an undergrad....lol

>>1866087
>>1866087
>>1866087
>>1866087
>>1866087
THIS!!!!!!!!!!!!

>>1866094
well, what is your background then?

>>1866096
>>1866087
OP will not be able to answer that buddy. Cuz if he could he would be in stockholm and not here like a troll

>>1866098
OP has a PhD in wikipedia and a masters in google.

>>1866098
What is your background?

>>1866102

BOOMF!!!

Whered you go OP?

>>1866087
I want my question answere.

>>1866087
Yes, possible in theory.

>If so why?

There is no theory that says they shouldnt exist, hence they "could" exist. There is no established conclusive train of thought that would prevent them. Afterall, there is nothing special about room temperture.

We really just won't know if they "exist", until we either build one, or dispove there existence theortically.

>>1866102
from the University of Internet

>>1866103
why are you answering my question with a question? i just wish to know your background, because personally, i'm finding it very hard to believe you're a physicist

>>1866120
I appreciate your efforts but your proof is weak to say the least. You simply say that something can exist because nobody disproved it yet. It's highly flawed because what if nobody tried to disprove it yet.... Maybe it is impossible but nobody tried to show that, and if they did they failed. I was looking for a physical answer, but a justification based on the current state of affairs in the field...

>>1866130
... is all you gave me.

>>1866128
I don't doubt that he is a Physicist. He obviously knows a thing or two about physics. But he is not a good Physicist ... All the good physicists are never out of their labs, and most definitely don't have time or care to answer questions of retarded newbs on 4chan....

OP cant answer my question becuz google has no answer
bahahah

hey OP why do spinning tops stand up?

>>1866138
the question here is not whether op is a good or bad physicist, the question is whether he actually is or isn't a physicist, and i find it hard to believe that someone who claims to have gotten a degree in physics from an university has no basic understanding of general relativity. it would be like majoring in physics from high school and having no basic understanding of newtonian mechanics.

the fact that he might know one or two things in physics doesn't necessarily implies he is a physicist, look at it this way, i'm not a medicine doctor, but if you ask me a question about medicine, i might be able to answer it, through personal knowledge (due to books or papers i read) or through searching it on the internet.

i asked op one simple question about general relativity that any person with a b.sc. in physics would have known because it is taught in college under general&special relativity classes, and to sum it up, as far as i've read from his replies, the explanations are very vague, lacking of details or any true deep knowledge as if he were reading it somewhere and rewriting them in his own words.

>>1866159

no OP but thats an easy one Centrifugal force.

>>1866174
so what is the centrifugal force, why does it exist and how can it make a top stand?

>>1866130
HA HA...I didn't do a "proof"
Ohh, Ic, you were actually trying to ask somthing else, you actually wanted to know if room temperature super condutcors can exist or not. The problem is that is not what you asked though. You asked about "theory"....lol

It seems like you dont understand how the burden of proof works in this scientfic concept, nor what a theory means scientifically.
"Theory" implies our current "theory" of superconductors. And yes, according to our current "theory", they might, as there is nothing special about room temperture as opposed to our current superconductor "low tempeture".
Hence, I answered your question perfectly, you just thought you asked a different question.
....lol

>>1866169
You just asked if photons interacted gravataionally, I answered your question already.

You must have phrased it bad or some shit, cause I cant see what you are getting at.

Photons are influenced by the warping of space time, by "gravity". This is a geometric influece of massive objects on the photons.

Did you mean to ask if photons have a gravitational effect on each other? If that was you question the answer is not directly. If you wanted to know about indirectly, let me know.

>>1866226
Not the other guy, but this is wrong. We don't have a quantum theory of gravity yet, but in such a theory, the photons have to interact with gravitons. Also, if you look at einsteins field equation, that which acts as a source of the gravitational field (or spacetime curvature if you wish) is the stress-energy tensor to which everything with energy and momentum contributes. Also, in GR, all gravitational forces can be seen as geometric influences of the curved spacetime.

y'all physics guys talkin' about quantum stuff, yet none of you wants to explain me how a siple top works

Why it is impossible to reach absolute zero temperature?

If it was possible to create a material which will absorb 100% of the light that hits it, would this object appear as a highly distorted material that is unnaturally dark, as in the dark shade of black possible?

I know it's not possible to do this of course, an object must reflect at least some light and heat also has to be created from light hitting it etc

still no answer about polarizer

>>1866280
I think I can answer this one; It is impossible due to heat always moving to a colder surface, if you can create a perfect vacuum surrounded by a material which does not conduct heat at all (impossible), then suspend a solid object at the center, you could cool it to absolute zero.

Someone correct me if i'm wrong

>>1866226
something interacts gravitationally if it has a gravitational field or in other words if it bends space around it. photons do bend the space around them so they interact gravitationally, even though their influence is extremely small. any physics undergrad knows that, it's basic general relativity. you stated that the only gravitational influence upon photons are due to the curvature of space by other bodies and this is not correct. photons have their own gravitational field.

>>1866312
actually the answers relies on statistical mechanics and it is much more complex than what you've described, which was the second law of thermodynamics.

>>1866257
..lol

I didnt say anything wrong at all. The problem is you are speculating shit that may or may not be true yet, .....in a "quatum theory of gravity".... LMAO. You are also using physics terminology wrong.

I repeat...just for you
Photons do not act on each other directly (as in the force carrier sense). They can act indirectly (as I stated already). The indirect sense would involve mometum/energy transfer through a massive object (what you were alluding to with GR). But of course, using this reasonging every fucking thing interacts with every other fucking thing....lol.

When refering to particles acting on eachother, the standard is to talk about "force carriers", as the GR and energy/momtum transfer is trivial.
Does this make sense to you now?

>>1866319
No, a photon (just moving through space without interacting) has no gravitation field. A gravitation field may occompany the photon, but it arises from massive particles, the results of interactions occuring in the photons path.

Why do you keep assuming a photon has some inherit gravitational field even though it has no mass? What part of only massive things curve spacetime do you not understand?

>>1866369
>massive particles
>Proton weight = 1.67×10^−27 kg
wat
l2physics

>>1866388
>doesnt know the difference between the proton and the photon

Ok yeah I am usually quite tolerant towards these kinds of mistakes, but confusing a proton with a photon is pretty bad.

Some things I don't get about light speed:

If your speed approaches the speed of light, time goes faster for an outside observer, so wouldn't they see you going slower?

Also, why can't light exceed c, even if its being shot out of a spaceship going at relativistic speeds?

Is it possible to create artificial gravity wells?

From an outside perspective, what's the last thing a person would see if a rock was plummeting into a black hole (assuming there was enough light to see it in space)?

How does one physically measure durations of time, and how does one physically measure the velocity of objects?

>>1866388

>proton weight
>kg

>weight in kg

>>1866444
Time slows down for you, which means that relative to you light would still travel at light speed away from you.

The last thing you would see was when the rock reached the event horizon.

I'm trying to determine if the speedometer in my car is correct, so i keep the needle at 70mph and time how long it takes me to travel a mile. It took me 56 seconds. Is my speedometer correct? is it too fast or slow?

>Why do you keep assuming a photon has some inherit gravitational field even though it has no mass? What part of only massive things curve spacetime do you not understand?

thanks, you just proved what i wanted to know. you're not a physicist at all.

>>1866511
What else bends space-time ?

>>1866458
i don't see nothing wrong here.

>>1866511

>>1866461
Thanks, but that doesn't really answer the first three. Would outside observers and myself see light traveling the same speed? Why?

>>1866369
>Implying only mass curves space-time and not mass-energy

>>1866536
>>1866521
Energy curves spacetime, dillholes.

>>1866540
You answered your first question yourself.

You both perceive light moving at light speed, shock huh? Only the light you send out would be blue shifted for the observer in comparison to you. Someone correct me if I'm wrong.

I'm not OP, so you should ask him about artificial gravity wells.

>>1866201
No actually there is no current theory for high temperature superconductors. You clearly have no clue what you are talking about....