Gravity: push, pull, or does not exist?

[Alkatran]

hey when i solved for p i got this:
p^2=E^2-mo^2c^4/c^2.. it's prob not right because it makes the answer imaginary (?)

An equation is only equal if you can take both sides and reduce them to 0.

yours now:
p^2=E^2-m^2c^4/c^2
0=E^2-m^2c^4/c^2-p^2
0=E^2-m^2c^2-p^2


original:
E^2 = m^2*c^4 + p^2*c^2
E^2 - m^2*c^4 - p^2*c^2 = 0

combine:
E^2 - m^2*c^4 - p^2*c^2 = E^2-m^2c^2-p^2
eliminate
E^2 - m^2*c^4 - p^2*c^2 = E^2-m^2-p^2
-m^2*c^4 - p^2*c^2 = -m^2-p^2
Multiply by -1 to remove minuses.
m^2*c^4 + p^2*c^2 = m^2+p^2

m^2(c^4-1) + p^2(c^2-1) = 0

As you can see, c has to equal one, or m and p have to have some odd values for this to work.


Also, is E^2 = m^2*c^4 + p^2*c^2 the actual equation, or is it E = m*c^2 + p*c? (I've never actually seen the equation before, and can't find any results on it)

 

[Nereid]

General caveat: Comments etc are wrt my current understanding of the status of observational/experimental results and the two most successful theories in physics - QFT and GR.

Why is it uncertain what happens beyond an event horizon?

Because there's no way any information can come back from inside it (qualifications: Hawking's presentation of earlier this week, the ergosphere)

Why is the cosmological constant still unsolved?

Because the observational data aren't yet sufficient to constrain alternatives.

Why is it that gravity is an attractive force,

Study GR and you'll understand how.

but the Universe is said to be expanding?

That's what we observe, so any theory must be consistent with the observations. In cosmological models consistent with GR, an expanding universe is one of the most natural ... consistent with observations!

How come there are black holes forming near the "beginning" of the Universe?

Excellent question! This is a very active area within cosmology; if you're interested, you can go to the A&C library, in the General Astronomy and Cosmology section, and read some of the papers to which links are provided.

Why is that when something gets more densed, there appears to be a more devestating effect of gravity? (Expert's opinion, like a highly credited site would be suffice. Since you people love math and experiments, provide me with some of those from a better source than Alkatran.)

Please clarify, e.g. what does 'more densed' mean? what is 'a more devestating effect of gravity'?

If nothing can move the speed of light, then how do neutrinos not have rest mass?

You may have heard of neutrino oscillations; when you understand these concepts you'll also find the answer to your question. Here's a good thread in PF that addresses this fascinating phenomenon.

Turning to how this thread began:

So assuming everything is governed by sub-atomic pressure, what creates this pressure? Simple, sut-atomic particles. Sub-atomic particles are going through our body every second in large quantities. One of the main sources of sub-atomic particles is from the sun in the form of neutrinos. Neutrinos rarely come in contact with masses, but if in a group that consists of enough, it can interact and actually exert a pressure on that mass. So...umm...guess on to an example of my theory.

So, one day, you are playing with a tennis ball. You are just throwing it up and down in the air. You begin to wonder, "What is really happening when I throw this ball in the air?" When the ball is in your hand, the sub-atomic particles hit it on all sides except where you palm grips it providing support on the bottom. When you throw the tennis ball in the air, you exert a pressure upwards on it, making it leave your hand. The neutrinos from the sun are unable to interact with the ball on the bottom side, so extra pressure is not applied, because the Earth acts as a shield for the bottom of the ball. Now, the tennis ball can go up, but it can only go up for a short while. Why is this? Gravity pulls it back down...no. The pressure that your hand exerted on the ball decreases as the sub-atomic pressure on the other sides of the ball overcomes the pressure exerted on the ball. With the pressure being less on one side, the other sides are being pushed in that direction (towards earth). The pressure on the other sides have pushed the ball back to earth, where it is now sub-atomic pressure equillibriate.

By now you'll see that your idea (it's certainly not a theory) is wildly inconsistent with observational data, so best put it to rest.

One point that no one raised: if neutrinos play a key role in this 'sub-atomic pressure', then an excellent place to test the idea would be around nuclear reactors. Close to these, the neutrino flux is many orders of magnitude greater than that from that Sun; ditto 'downstream' from particle accelerators. So, any effect like the one you propose would be much more obvious there than elsewhere on the Earth. Since no such effects are observed, you have a tough job ahead getting your idea accepted!

urtalkinstupid 0, QFT+GR 1.

 

[beatrix kiddo]

oh ok.. nvm then.. sry alkatran.. i misread ur post... I CAN BE WRONG TOO YA KNOW!

i already apologized for getting it wrong... so now what? and the equation is correct http://www.physlink.com/Education/AskExperts/ae476.cfm
but thanks for helping out with it...

 

[beatrix kiddo]

i can't find a source that says the neutrino flux mag. is greater in the particle accelerators than from the sun... could u please provide me with further information that i may reasonably defend my case??

 

[Entropy]

Why are we arguing about the momentum equation or whatever? The TOTAL (includes momentum and mass) energy of the average neutrino passing through Earth is 0.81MeV like I said.

 

[beatrix kiddo]

so that i don't make the same mistake again, alkatran i'll show u my steps and u tell me which i did wrong..
E^2=m^2c^4+p^2c^2
E^2-p^2c^2=m^2c^4
-p^2c^2=m^2c^4-E^2
-p^2=m^2c^4-E^2/c^2
or p^2=E^2-m^2c^4/c^2

maybe i didn't do it wrong.. if so disregard this

 

[beatrix kiddo]

entropy we're trying to solve for momentum.. we all know the energy but if u know how to solve for p that would be most appreciated..

 

[ArmoSkater87]

Why are we arguing about the momentum equation or whatever? The TOTAL (includes momentum and mass) energy of the average neutrino passing through Earth is 0.81MeV like I said.

I really think that that's wayyyyy too big for a neutrino.

 

[ArmoSkater87]

I think this is the best and easiest way to solve for momentum...

E^2 = m_0^2c^4 + p^2c^2
\frac{E^2-m_0^2c^4}{c^2} = p^2
p=\frac{\sqrt{E^2-m_0^2c^4}}{c}

 

[urtalkinstupid]

No, that always yields an imaginary number. Yes, it utilizes all of the right steps, but the answer is never within reality.

Entropy, I know the total energy of the neutrinos. I'm trying to find the momentum that is included in the total energy. Is that clear to you?

Nereid, you make me sick. One, you break up a complete question and give partial explanation. When i asked, "Why is gravity an attractive force, but the Universe is expanding?" I meant that as ONE question. I didn't mean for it to be broken down into two questions with separate definitions. Experiment and observations don't mean anything. Logic is the ultimate determining factor of how things work. You raise a good question about nuclear reactors. How would the flux be of a greater magnitude, when it has not near the fusion power of the sun? Or does it? If it does, can you please provide me with a source.


Oh, you made the comment urtalkinstupid 0, QFT+GR 1. Well, I have news for you buddy. QFT+GR does not exist as one. They can not be combined as of yet, because they do not allow unity. So, QFT+GR 0, urtalkinstupid 1+n

(n increasing by one for everyday QFT and GR remain in disunity)

 

[selfAdjoint]

Experiment and observations don't mean anything. Logic is the ultimate determining factor of how things work.

You're talking stupid.

 

[urtalkinstupid]

selfAdjoint, experiments really don't mean anything. If you pay close attention the math that they used in the experiments was derived from other things. Math is a manifestation of logic. Logic made math. The new string theory sounds way more logical than the theories out today. Logic says that QFT and GR can be unified, but as of yet they haven't. Why? The logics within the two fields are not compatible. Why? They both consist of math that is not logically possible. Things attracting other things depending on their distance and mass...Yea, right. String theory fits into my theory, because it involves emission and absorption. How did this universe start? A string. How did this strnig become? The universe was asymmetrical; it had to equal out somehow so it emitted energy so it could be absorbed and so on.

QFT+GR 0

 

[Nereid]

When i asked, "Why is gravity an attractive force, but the Universe is expanding?" I meant that as ONE question. I didn't mean for it to be broken down into two questions with separate definitions.

Perhaps you could be more precise in your wording then? For example, "We observe that the universe is expanding. However, gravity is a long-range, attractive force. How is it that the universe can expand against gravity?"

Experiment and observations don't mean anything. Logic is the ultimate determining factor of how things work.

If you would like to discuss physics, or any other science, you will need to adjust your expectations; AFAIK, only in maths is 'logic the ultimate determining factor'. In the meantime, I will continue to demonstrate inconsistencies in your ideas by referencing experimental and observational results.

You raise a good question about nuclear reactors. How would the flux be of a greater magnitude, when it has not near the fusion power of the sun? Or does it?

Because the Sun is ~150 million km from you, and near a reactor the distance is ~150m. Assuming both the Sun and a reactor radiate neutrinos isotropically, then the Sun would need to produce neutrinos at a rate >10²⁷ of that of a reactor for an approx equal (local) flux. Stay tuned for links.

 

[Nereid]

You raise a good question about nuclear reactors. How would the flux be of a greater magnitude, when it has not near the fusion power of the sun? Or does it? If it does, can you please provide me with a source.

Try http://www.bnl.gov/bnlweb/history/nobel/nobel_02.asp: "... the probability of chlorine's capturing a neutrino was ten quadrillion times smaller than its capturing a neutron in a nuclear reactor." It refers to Cl, but the statement for any other target is similar.

 

[Alkatran]

so that i don't make the same mistake again, alkatran i'll show u my steps and u tell me which i did wrong..
E^2=m^2c^4+p^2c^2
E^2-p^2c^2=m^2c^4
-p^2c^2=m^2c^4-E^2
-p^2=m^2c^4-E^2/c^2
or p^2=E^2-m^2c^4/c^2

maybe i didn't do it wrong.. if so disregard this

-p^2=m^2c^4-E^2/c^2
That step is wrong, you need to divide the ENTIRE side by c^2.

The funny thing is that this is the exact same error I predicted you had made.

 

[urtalkinstupid]

Alkatran have you ever seen that equation before I introduced it to this thread?

 

[beatrix kiddo]

urtalkinstupid just pwnd nereid..

come on dude.. u can do better than that. all that told me was that neutrinos are hard to detect. BFD. "The detectors count roughly one-third of the expected number of solar neutrinos... The other two-thirds of the electron neutrinos would have become tau or muon neutrinos, which the Davis experiment could not count." foundations of astronomy pg. 169. think oscillation, nereid. i want data that shows the magnitude of the neutrino flux is greater "downwind" from a particle accelerator. also that site says only 400 bil neutrinos hit the Earth when it is actually 500 tril. that link was just a bio! that guy didn't even write it. it takes u an hour to come up with that?! give me numerical data determining the magnitude of the neutrino flux from the particles accelerator.

 

[beatrix kiddo]

alkatran i did! i just didn't use parenthesis and i don't know how to type in that math symbol junk

-p^2=m^2c^4-E^2/c^2
That step is wrong, you need to divide the ENTIRE side by c^2.

The funny thing is that this is the exact same error I predicted you had made.

HAHAHAHAHA.. don't pretend to be psychic..

 

[urtalkinstupid]

Nereid, ummm, nice arguement? I'll take part of your advice!

We observe that the universe is expanding. However, gravity is a long-range, attractive force. How is it that the universe can expand against gravity? Answer, please.

So, QFT and GR...Would you like to tell me why they are unable to form a partnership? If so many of the current theories work through observation and experimentation, why is that not true when you try to combine QFT and GR? Obviously, there is something wrong with the way the two branches of science work.

Nereid, I would ike to know your view on gravity. Do you believe it is a pull or expressed through the inclination of space-time? Do YOU think neutrinos have a rest mass? Do you think they travel at the speed or light or just under the speed of light? Do you think the binary star system that is orbiting the black hole in the middle of the milky way has any significance? Do you think Hawking's new explanation about black holes is correct, or is the old theory still suffice?

 

[Nereid]

urtalkinstupid just pwnd nereid..

come on dude.. u can do better than that. all that told me was that neutrinos are hard to detect. BFD. "The detectors count roughly one-third of the expected number of solar neutrinos... The other two-thirds of the electron neutrinos would have become tau or muon neutrinos, which the Davis experiment could not count." foundations of astronomy pg. 169. think oscillation, nereid. i want data that shows the magnitude of the neutrino flux is greater "downwind" from a particle accelerator. also that site says only 400 bil neutrinos hit the Earth when it is actually 500 tril. that link was just a bio! that guy didn't even write it. it takes u an hour to come up with that?! give me numerical data determining the magnitude of the neutrino flux from the particles accelerator.

I think it's time for you to do some research of your own; you have the resources of the internet at your disposal, and (clearly) a great deal of time on your hands.

Here is one place that you may like to start. You may also find some issues of the CERN courier of interest, for example. If you follow the links provided in these pages you will also learn a great deal about neutrinos.

 

[urtalkinstupid]

Nereid, you have no response for me? I feel left out.

 

[Nereid]

Nereid, ummm, nice arguement? I'll take part of your advice!

We observe that the universe is expanding. However, gravity is a long-range, attractive force. How is it that the universe can expand against gravity? Answer, please.

A very good place for you to find an answer to this excellent question is Ned Wright's Cosmology tutorial. You could also read some of the posts by marcus, esp in the General Astronomy and Cosmology section of PF.

I'm not avoiding your question, merely pointing out that I don't think I could adequately answer it in 10,000 characters or less.

So, QFT and GR...Would you like to tell me why they are unable to form a partnership?

In the Physics section of PF there is a sub-section Strings, Branes & LQG. There you will find many excellent answers to your question. If you have access to a local library, you will find a book by Brian Greene, called 'the elegent universe' - I recommend that you borrow it and read Part II.

Again, your question is best answered by something much longer than a post in PF.

If so many of the current theories work through observation and experimentation, why is that not true when you try to combine QFT and GR?

Because the physical domains where the two theories are significantly inconsistent are ones we have no direct access to, such as the first Planck 'second' of the universe, or colliding neutron stars.

Obviously, there is something wrong with the way the two branches of science work.

If you mean, 'there are inconsistencies between QFT and GR', then yes; if you mean 'there are observational or experimental results which are inconsistent with QFT or GR', then no. If there were inconsistent results, we could get some hints on how to go about working out a better theory (or two).

Nereid, I would ike to know your view on gravity.

My view is that GR provides an exceptionally good explanation of gravity, because every test that it has been subject to, it has passed. It's also a very elegant theory.

Do YOU think neutrinos have a rest mass? Do you think they travel at the speed or light or just under the speed of light?

The experimental and observational data support the concept of neutrino oscillations. Did you read the material on the link on this topic that I provided in an earlier post? If so, what in that material did you not understand about neutrino oscillations?

Do you think the binary star system that is orbiting the black hole in the middle of the milky way has any significance?

I don't understand your question; would you please rephrase it?

Do you think Hawking's new explanation about black holes is correct, or is the old theory still suffice?

Not having even read it, I am in no position to have an opinion.

 

[Alkatran]

alkatran i did! i just didn't use parenthesis and i don't know how to type in that math symbol junk


HAHAHAHAHA.. don't pretend to be psychic..

You're kidding, right? How can you expect us to tell you if your equation is right if you won't even use parathenses!

And I'm not psychic, but not pretending either. A few pages back I posted what you probably did to reach the error and it was very similar.

 

[urtalkinstupid]

I'm not avoiding your question, merely pointing out that I don't think I could adequately answer it in 10,000 characters or less.

I would love for you to answer my question. I have an e-mail address. You could send your answer there.

None of your answers are what you think. They are what other people think. I want your personal opinions. Once again, you took a question and broke it down. I wanted to know your views on gravity. I provided you with two optionms that were: push or space-time curvature. People have told me that these are two different concepts but the "pull" is used as a term of convience. There is no such thing as a pull anyways.

There is a massive black hole in our galaxy. This massive black hole was noted to have a binary star system orbiting it. I think this has a great significance. I wanted to know if this binary star systems strikes a nerve in your brain at all.

The current theories are presented as flawless. We all know that they leave many questions unanswered. So, why are they so accepted?

I would really like to hear YOU answer my questions rather than giving me other sources.

 

[Alkatran]

The current theories are presented as flawless. We all know that they leave many questions unanswered. So, why are they so accepted?

I would really like to hear YOU answer my questions rather than giving me other sources.

If anything, the current theories are presented as flawed. We know that there's probably some tiny drift here or there that we haven't accounted for.

 

[urtalkinstupid]

Alkatran, I asked you earlier if you have ever seen Einstein's total energy equation before i presented it. So, have you?

 

[beatrix kiddo]

uh. ok nereid. i read ur sites and they provided me with information I've known about for the past 2 yrs. i never said i needed to know more about neutrino detectors, etc. i asked u to provide me with data that showed the magnitude of the neutrino flux is greater downwind from a particle accelerator. where in any of those sources does it discuss that?? u say that i need to go out and research neutrino flux mag. increase downwind from a particle accelerator and I've tried but (SUPRISINGLY!) i can't find any sources. this whole bit was ur idea and i want to know how u came up with it and what sources u used to back it up.

 

[beatrix kiddo]

You're kidding, right? How can you expect us to tell you if your equation is right if you won't even use parathenses!

And I'm not psychic, but not pretending either. A few pages back I posted what you probably did to reach the error and it was very similar.

alkatran from now on i'll include every little parenthesis, or what have u, so u don't get confused and see it as a chance to unnecessarily correct me...
what error?! we came out with the same equation p^2=(e^2-m^2c^4)/c^2.. i hope u're as good at reading as u are with math

 

[urtalkinstupid]

Here is beatrix kiddo's equation in an easier to read way:

p^2=\frac{E^2-m_0^2c^4}{c^2}

I'm sure you can read that, Alkatran.

 

[Integral]

all mass bends light

only black holes have sufficient mass to bend it to where we can detect it.

Wrong! The first verification of GR came from the measuring the bending of light as it passed the sun. Do some research on Gravitational lensing.

 

[urtalkinstupid]

terrabyte got SERVED...

Thanx Integral.

 

[urtalkinstupid]

Also, terrabyte, I've never noticed how much error you have in that statement. If black holes have sufficient mass, doesn't the neutron star it was born from have sufficient enough mass also? This sounds like a density problem.

 

[beatrix kiddo]

Wrong! The first verification of GR came from the measuring the bending of light as it passed the sun. Do some research on Gravitational lensing.

HAHAHAHAHAHAHAHA- ownage! now all we have to do is sit back and wait for terrabyte to get all defensive and revert to personally attacking everyone on this thread...

 

[Alkatran]

Alkatran, I asked you earlier if you have ever seen Einstein's total energy equation before i presented it. So, have you?

No, I never saw it before this. But I already said that, or at least hinted at it by asking about it.

Here is beatrix kiddo's equation in an easier to read way:

Unless you couldn't tell, I was writing all my equations out the way I normally do in programming. I'm used to seeing 5+ levels of parathenses. If you're going to write an equation WRONG, don't make fun of people who read it the way you WROTE it instead of the way you MEANT it.

Also, terrabyte, I've never noticed how much error you have in that statement. If black holes have sufficient mass, doesn't the neutron star it was born from have sufficient enough mass also? This sounds like a density problem.

How does this sound?:

If you are OUTSIDE something, it doesn't matter how much you shrink or expand it, the force of gravity stays the same (this is the conclusion I came from with my point-summing program).

If you are INSIDE something (see: star to black hole) the force WILL get stronger as it shrinks. Until you are OUTSIDE it again. After that the force will stay the same.

From this comes the obvious conclusion that the radius of the event horizon of a black hole is much smaller than the radius of the star it came from.


The reason that force goes down when you're inside something is you ignore the shell around you. It is geometricly proven that if you are within the shell of a sphere or circle, the sum of the (the axes that make up vectors? Sorry, french education, don't know the term) of the inverse of the distance squared from all the points of that shell total out to 0.

 

[beatrix kiddo]

i thought u (of all ppl) would have understood that the division slash i used was meant to divide that entire side. i mean.. it's basic algebra, right? I'm not an idiot alkatran..
what do u mean it doesn't matter how far u shrink something?? let's say we've got a binary star system. the stars are "pulling" on each other but they are not overpowering each other to the point where one of the stars starts directly falling into the other. however, one of the stars becomes a neutron star. how come the neutron star's partner begins to fall into it and form an accretion disk if the mass hasn't changed but density has?? (neutron stars have the same mass as the stars they came from..2 to 3 solar masses)
"binary pulsars can emit strong gravitational waves because the neutron stars contain large amounts of mass in a small volume. this also means that binary pulsars can be sites of tremendous violence because of the strength of gravity at the surface of a neutron star." foundations of astronomy pg.290.. man i love this book..

 

[urtalkinstupid]

Wow, a diecast Einstein fan has never heard of Einstein's total energy equation...Weird...

Yea, I program also, so I know what you are used to. beatrix kiddo doesn't program, so she didnt' know.

The equation for calculating the force betweent he objects is not correct. The reason why it doesn't change force, is because you are not including density. Take a ray of light. It is passing throught he vacuum of space. A neutron star is approaching. This neutron star is more dense than the star it burned out from. This more dense star has affects of gravity that seem to be stronger, but the equation doesn't sohw this excess force. Around this object, light is bent more than it would have been if that object were less dense. Why? The object light is able to get closer to the center of gravity of the object. Why? The object is more dense, it has less volume but the same mass. Ok, the density of objects may not have an affect on huge objects, but the affect on light is visible. Now, that star condenses into a black hole. Same mass, but zero volume. Light is bent backwards. The density of objects has an gravitational affect on objects with a velocity towards the denser object? If the object is taking a path then, if the object it were traveling to were to get more dense, then the object with velocity would take a natural path towards the dense object, therefore allowing that object to get closer to the denser object's center of gravity. Which leads to more devistating gravitational effects.

Arg, I can not explain it how I want to. I'll figure out a better way to explain it. In all seriousness, you can not go by what Einstein taught if you have never heard of his total energy equation. That's pathetic. I don't think Einstein should be credited for much, but even I have heard of that equation.

 

[terrabyte]

Thanks Integral for inciting the young'uns :|

all mass bends light

only black holes have sufficient mass to bend it to where we can detect it.

Integral: Wrong! The first verification of GR came from the measuring the bending of light as it passed the sun. Do some research on Gravitational lensing.

in case you guys were too giddy with joy to notice, he was saying wrong to the second part, not the first.

which does nothing to validate your case at all, so you can wipe the smirks off your faces.

as far as neutron stars go see Integral's above reference to how even our own suns' mass bends light. it's NOT a density issue. go to the back of the class, "stupid"

HAHAHAHAHAHAHAHA- ownage! now all we have to do is sit back and wait for terrabyte to get all defensive and revert to personally attacking everyone on this thread...

poor guy, laughing at his own ineptitude...

 

[beatrix kiddo]

tisk. tisk. terrabyte... i knew u'd return to post ur puerile opinion sooner or later. i guess it took u a bit longer to reply because a mentor "stirred" us up and we got a bit too rowdy for ur comfort level. uh.. what makes u think we thought he said the first part was wrong? it's cute that u underestimate my comprehension by assuming i can't read.. cough.cough. and, unlike u, I've read my history and i know that gravity bending light was first noticed around the sun. and how am i laughing at MY foolishness when u're the one who came back, like i said, got personal, like i said, and poorly defended urself, like i said. HAHAHAHA... that's ineptitude for u.

also... do u have anything to say about my post and my book source describing binary star systems and density?? i know u saw it, so instead of pulling a typical terrabyte just stick to the physics.. please.

 

[terrabyte]

why don't you post the whole thing so we can see what it says in context instead of vicariously through your insipid excerpts?

you could also post the copyright date as well

 

[quantumdude]

This is just about the silliest thread I have ever seen. It was brought to my attention by one of the Mentors, and so I started going through it. I was editing the thread, deleting personal attacks and inane babbling, when I finally got sick of it around Page 13. This thread is done.

For future reference: Physics Forums is not a chat room for children. If that's what you are looking for, then go to MSN or Yahoo or something.