Does acceleration greatly affect gravity

[Bignose]

gravity is a force and a force is proportional to acceleration. Force is equal to acceleration times a proportionality constant.

 

Saying "contains gravity but does not contain any type of accelerating force" is completely meaningless.

 

If there is gravity, that means there is a force; and if there is a force that means there is acceleration. This is one of the very most basic definitions of physics. If you are having trouble with this, please go and read and Introduction to Physics book. Your library should have several to choose from.

[floersh]

Here is a good way to think of it.

 

Spinning objects produce centrifical force as described before. Take a bucket and fill it with water. Tie a rope to the bucket and spin it around in a circle. Even if you spin it upside down the water will remain in the bucket. That is not gravity that is centrifical force.

 

Note in the above that the water was contained on the outside of the circle. (Aka by the bottom of the bucket that was facing away from the central spining point).

 

Now if gravity was the result of spinning don't you think since we are all sitting on the bottom of that proverbial bucket (aka the surface of the earth) that we would be thrown away from the earth rather than attracted toward it? Wouldn't we need to be on the inside of the earth in order to feel gravity?

 

To fully illustrate my point. Take that bucket again and attach the rope to the bottom of the bucket so the open end points outward and spin it around. The water flys out in all directions doesn't it?

[someguy]

I know what you guys are saying but i think what killa klown is saying still has merit. i think he is trying to say that all things that warp space-time are constructed of smaller parts that are moving. and this seems indeed true except for perhaps the smallest indivisible particle or string however you want to imagine it. and therefore you must wonder what it is about that smallest thing that allows it to have mass since it is no surprise that the motion part of the building blocks accounts for mass but the motion part is always an additive. you can increase mass by moving it but you can't use motion to create mass from scratch at least i don't see how. motion of a massless thing does not create mass or else we could create mass by moving light. and i don't think we can but it would be fun to try. so killa klown i can't think of any either but i also don't know what the smallest indivisible thing in the universe is like and i don't know where it gets its mass from, but if something smaller then that is moving then it is not the smallest indivisible particle, therefore i am leaning towards thinking that this thing has mass and is not composed of smaller moving parts. but i can't imagine what stuff is like when you go that small so we'll have to leave it at "i can't think of anything that has mass and is not composed of smaller moving parts" because we probably will never find one not in our lifetime at least, but still that isn't to say that there isn't one. at least i think that's what you were getting at right?

[Killa Klown]

Floersh, you mentioned how a bucket of water is spun and the centerial force is what kept the water inside the bucket (great example by the way). Now I was wondering, would that example also apply to a great sphere of mass with it's own atmosphere. See the reason I post this post is because I also put much thought into it and thought to myself "If the theory I'm concieving is true then everything on earth would be thrown into outer space." until I remembered "The earth has an atmosphere" meaning that there is pressure, and that pressure maybe what could be holding us down on earth, could pressure be the very key to the force of gravity. (Please correct me if I'm am wrong, Humans do learn from their mistakes).

 

Well someguy, not to disapoint you, but you are half right about what my point is. What I'm actually trying to say is that mass by itself cannot create gravity. Yet according to newton's law of gravity, (correct me if I'm wrong) Gravity is dependent on MASS. So yeah your kind of are right someguy about how there is no known force of gravity created without mass.

[Bignose]

You've got it backwards, KK. The atmosphere is present due to the presence of gravity, not gravity is due to the presence of an atmosphere. Gravity keeps the atmosphere on the Earth.

 

If atmosphere was the cause of gravity, shouldn't the atmosphere in the International Space Station or on shuttle missions be creating gravity? There is an atmosphere on those spacecraft, but just watch any of the videos from those craft and the people inside are clearly weightless.

 

And, here's why. Pressure in a fluid acts in all directions equally. That is, the pressure at a given point in a fluid pushes up and down and left and right and back and forth all at the same time and all at the same strength. So, the pressure from the atmospheres in the aforementioned spacecraft push on the people in every direction equally. So, even though those spacecraft have an atmosphere, the occupants still are weightless.

 

I can understand your desire to figure out the mechanics of gravity -- it is quite a puzzle that has so far eluded many, many extremely talented scientists. But, I just cannot understand your denial of the fact that there are innumerable experiments that show that the amount of gravity is a function of an object's mass and the distance from that object... and nothing else. Considering the many, many successes using that rule to predict how objects behave, what is the motivation for looking for something else? Successes include being able to predict the motions of the planets/comets/asteroids, launching probes to land on other planets and near other planetary moons and comets, launching satellites into orbit, etc. etc.

 

I almost cannot believe I am doing this, but you should look into the Pioneer Anomaly. This is actually one case where what we thought we knew and we predicted was not what was observed. Some of the deep space probes have had some small unknown forces acting one them. And one of the many possible explanations is that Newton's Law of Gravity may not be exactly 100% right -- that for accelerations under 10^-10 m/s^2, there may be a different form of Newton's Law that applies. But, there are many other possible explanations too, including errors in the mass of some of the objects in deep space (like the Kuiper belt), our incomplete understanding of dark matter, the spacecraft itself may have had a slow leak of a gas, the solar wind, or maybe even incomplete communication and simple statistical error. We may never know for sure, but there are lots of possibilities, and compared with the millions of successful predictions Newton's Law of Gravity has been used for, a few tiny errors on a few deep space probe is no reason to toss out or radically change Newton's Law like you are promoting including rotation into the Law.

[Killa Klown]

OOOHHHH! Well like I mentioned humans make mistakes, it's in our nature. I appriciate the time you took to explain you ideas to me. I know see gravity as it truly is in the eyes of a scientific mind with experience. I just couldn't accept how mass can have such an effect on space-time, it just didn't make ANY sense what so ever to me. Thanks to many of these post (including yours) and can now finally let go of my radical idea of acceleration being the sole purpose gravity exist (besides MASS).

[floersh]

Floersh, you mentioned how a bucket of water is spun and the centerial force is what kept the water inside the bucket (great example by the way). Now I was wondering, would that example also apply to a great sphere of mass with it's own atmosphere. See the reason I post this post is because I also put much thought into it and thought to myself "If the theory I'm concieving is true then everything on earth would be thrown into outer space." until I remembered "The earth has an atmosphere" meaning that there is pressure, and that pressure maybe what could be holding us down on earth, could pressure be the very key to the force of gravity. (Please correct me if I'm am wrong, Humans do learn from their mistakes).

 

Well someguy, not to disapoint you, but you are half right about what my point is. What I'm actually trying to say is that mass by itself cannot create gravity. Yet according to newton's law of gravity, (correct me if I'm wrong) Gravity is dependent on MASS. So yeah your kind of are right someguy about how there is no known force of gravity created without mass.

 

Well think of it this way. Pressure is applied in all directions simultaneously. So the atmosphere is not only pressing down on you but also up on you. The two (and its really millions of different force vectors) all cancel one another out.

 

Now there is another way to think of it. Strength of force. Centrifical force is strong enough to over come gravity. (Aka the reason you can spin that water bucket upside down and the water does not fall out).. It can also overcome pressure (otherwise you wouldn't be able to spin the bucket)..

 

Also you should keep in mind that atmospheric pressure is the result of gravity not the otherway around. If a large body like the earth did not have a strong force pulling down on the gas particles (aka our atmosphere) the gas particles would all be flung into space just as you and I would be.

 

Also if you want to apply centrificl force to a large planet like the earth think of it this way. The earth rotates on its axis and around the sun and around the galaxy and around the universe. But if we make it simple and just take into account its rotation and its rotation around the sun. You will note that every part of the earth is on the outside of that centrifical force vector at ssome point during a 24 hr period..

 

And if this was the case we would experience varying strengths of force. It would be throwing us out when we were facing away from the sun (aka at night) and pulling us harder toward the surface during the day (aka when we were facing the sun). Now I can stand on a scale any where in the world at any time and I always weight the same.. So the only way it could be related to centrifical force is if all the combined motions put together all equaled out as a constant force vector toward the center of the earth..

 

You would be hard pressed to find circular motions that resulted in that.. There would always be a variance.. Even if it were possible to contrive a pattern of motion that would create a equal force vector toward the center of the earth it would be impossible to do both the earth and say mars without the two being located in the same place..

 

Now it is possible that motion at a subatmoic level may have something to do with gravity.. But there is not doubt that gravity does exist.. And that at a macroscopic level it has nothing to do with motion..

[someguy]

i think the thing is motion IS mass... sort of. energy is mass and motion is energy. but motion only adds to mass. motion of something massless does not add to mass. so light can have no mass and yet move. it's the only thing that can do that. it's the only massless energy. there is something inherently different about light than any other thing that exists. at a macroscopic level gravity does indeed have to do with motion. mass increases as velocity increases. quantum or not. you could define mass as propensity to bend space-time therefore by definition mass must be necessary for gravity, however the thing is what is mass made of? part of it is motion. you could even say most of it is motion. but if light moves and has no mass it can't all be motion, there's something responsible for the initial mass that light doesn't have. you could take a mass n-->0 and spin it around in a circle at velocity v-->c and you would have increased it's mass and then you could take that 'ring' and spin it on an axis at v-->c and it would make like a sphere, and then you could take that sphere and do the same, make another ring with it and continue doing this eventually your mass of n-->0 would be substantial, i'm not saying that quantum particles are doing exactly this.. but they are definitely doing something similar. but there must be a mass n-->0 to begin with and light doesn't have this whatever it is. unless light IS a mass of n-->0 and then we could have a plausible answer. but then it couldn't be moving at c because it has mass and therefore would have infinite mass at that velocity. in a sense mass is nothing more than a high concentration of energy. but to be exactly that and not just sort of, light would need a mass of n-->0 and not n=0. if light has a mass of exactly 0 then there is something elusive responsible for mass that motion aggravates.