Well, if Newton's Third Law says that "For EVERY action, there is an equal and opposite reaction.", then how does the entire scientific world make this one exception for gravity? And if matter is the "force" keeping you from falling, could it be possible that gravity is caused by antimatter?
2007-12-04 22:44:52 · 10 answers · asked by chizzle_30 2 in Science & Mathematics ➔ Astronomy & Space
the magical pony makes gravity
2007-12-04 22:52:32 · answer #1 · answered by shippo 2 · 0⤊ 1⤋
Regarding Newton's 3rd law, the "opposing force" (or 'reaction') to gravity is a different gravity force acting on another body as one of the above answerers already pointed out. Gravity does obey Newton's 3rd law.
Thinking that something has to counteract gravity is the wrong way to look at it.
Thrust and drag are not Newton's 3rd law forces, either. The reaction force to the thrust of an engine (I'm thinking of a rocket engine) is the force on the exhaust particles. The reaction force to air drag on a rocket is the force the rocket applies to the air.
As far as I know no one has any idea why mass is like a gravitational "charge". Saying that mass causes gravity doesn't really address why it does. It's a wonderful and puzzling thing to think about.
When you mentioned antimatter it made me think about experiments to test whether gravity affects antimatter the same as matter. Have those experiments been carried out yet?
2007-12-05 09:43:17 · answer #2 · answered by Steve H 5 · 0⤊ 0⤋
How many times are you planning to ask this?
The Newton's Third Law reaction to the Earth's gravity on you is your force of gravity on the Earth. Action-Reaction forces are always the same kind and always act on different objects.
The reason you don't fall through the floor is the normal force pushing up on you. The normal force is NOT the Third Law Reaction to gravity. It's just another force we feel in common everyday life. The reaction to the normal force of the floor pushing you up is the normal force of you pushing down on the floor. If you were heavy enough, you would exceed the material strength of the floor and fall through it.
Gravity is caused by any mass, whether it be matter or antimatter, but there is no antimatter in the Earth.
EDIT: Oh, and it needs to be said that Thrust and Drag aren't an action/reaction pair either. The reaction is ALWAYS the same force acting on a different body. The reaction to the air pushing the propeller forward with a thrust force is the propeller pushing the air backwards with a thrust force. The reaction to the fluid resistance of the air dragging the airplane backwards is the airplane dragging the air forwards.
2007-12-05 07:02:55 · answer #3 · answered by ZikZak 6 · 3⤊ 0⤋
1) there is no exception for gravity:
If the Earth pulls on you with a force of 150 pounds, then you pull on the Earth with a force of 150 pounds. That is the equal and opposite reaction.
The Earth, being more massive than you, will not move as fast and, eventually, will not break a leg when it hits you. That is the unfair part.
2) The matter that keeps you from falling causes you to feel "weight". The weight (force pushing you upwards) is equal to the force imparted by gravity (otherwise, you'd move; either upward or downward).
Gravity (if unchecked by intervening matter) gives you acceleration. You accelerate towards the Earth, the Earth accelerates towards you. When matter gets in your way, you break a leg.
3) We still do not know what "causes" gravity.
We know that it is proportional to mass and inversely proportional to the square of the distance and that extreme conditions (relativistic speeds, extreme speeds, ambient energy such as light) will affect the calculations.
So, we can predict its value but we do not know what causes it. We think that it can be explained as a curvature of space-time by the presence of mass, maybe through the Higgs field. But, have you even seen a curved space-time continuum first-hand (or first-eye)? Be honest now.
And when is the last time that you actually felt that the Higgs Field was giving you the mass that you would not have otherwise?
2007-12-05 09:59:52 · answer #4 · answered by Raymond 7 · 0⤊ 0⤋
I'm just your average guy but here's how I understand it...
Gravity is "caused" by mass. This means that more massive objects exert more pulling force than less massive objects. Take black holes for example, they're known for their extreme gravitational pulls. Conversely small satellites (or moons) exert only enough gravity to, let's say, affect the tides here on earth.
And regarding Newton's 3rd law...I think you're getting it wrong. Yes, for every action there is an equal and opposite reaction but it's not meant to apply to forces per se. What you're asking is analogous to asking what's the counterforce of acceleration? (Not friction or air resistance, etc. since acceleration also exists in space) It simply doesn't have an antagonist counterpart.
As for anti-matter, it is a totally different topic altogether.
2007-12-05 07:02:48 · answer #5 · answered by Immatellonu123 4 · 0⤊ 1⤋
You are using an example of Newton's third law in a twisted form. Gravity is not an action. it is a force. The force of gravity has one opposing force in nature,it is the opposing force of radiation that maintains the stability of a star.
2007-12-05 12:27:20 · answer #6 · answered by johnandeileen2000 7 · 0⤊ 1⤋
Strickly speaking, As per the modern Physics, Gravity is a fundamental property of Matter is caused by an agent called
"GRAVITON". Graviton (a Boson) is present in every matter(if you say that is matter) and is solely responsible for the gravity.
Ultimately which gives rise to Newtons Gravitational law, New tons thrid law etc.
Existance of Graviton is yet to be proven by Quantum mechanists and particle physicsts.
2007-12-05 07:25:58 · answer #7 · answered by kay kay 4 · 0⤊ 1⤋
gravity is caused by mass. ex. earth has gravity to pull me down, the reaction is I also have gravity that pull the earth up. but because my mass is so small compared with the earth's mass we don't see that i pull the earth up. if i didn't have any force / gravity to pull the earth up, i will sink into the earth.
F=(Gm1*m2)/(r)
force of gravity is equal to G constant times the first matter's mass times the second matter's mass divided by the distance between the centre of those matters
2007-12-05 09:27:54 · answer #8 · answered by Ahmed El arf 2 · 0⤊ 0⤋
If acceleration due to gravity is prevented from occurring by the resistance of the surface, where is the action that requires a reaction?
2007-12-05 08:56:04 · answer #9 · answered by Anonymous · 1⤊ 1⤋
It's caused by gravitons interacting with other particles!
2007-12-05 11:54:04 · answer #10 · answered by Anonymous · 0⤊ 0⤋