ANSWERS: 42
  • I just stepped off my chair and fell to the floor - I'd say its a fact.
  • gravity is a law and not a theory, because it has been proven to exist...
  • it is a law..
  • its a theory, the force is there, none can figure out how it works though, or why it is there.
  • It's a fact. We develop theories to explain and give some predictability of observed phenomena, and when these theories attain sufficient respectability from behaving consistently, we anoint them as laws. By this time, they should incorporate mathematical formulae that forecast behaviors. Gravity has a very exact formula for stating its effect, and it is predictable and consistent.
  • Well, "Gravitational Theory" is our explanation of the phenomenon we know as 'gravity'. It is a law of gravity that if you drop an object here, it will fall to the ground, but it is Gravitational Theory that explains how and why this occurs. Gravity is a law, but we understand and explain it through a theory. It is both ; )
  • It would be a theory for many have defied gravity.People have levitated objects and their own bodies. I am not talking of magicians but the saints of India.
  • It is a reality!
  • Since it is proven, it is no longer a theory, it is a a law.
  • When was the last time something fell up? I'd go with the fact that it's a law, explained with a theory.
  • A Scentific Theory and Law. Again everyone, there's a grand difference between a theory and a scentific one.
  • As a physicist... I say it depends on what you call gravity. The effection of attraction between two bodies with mass is a LAW, the reason for this on the other hand we are still investigating (e.g. is it a curvature in time-space? Does it propagate via the photon)
  • first of all..gravity and all forces of nature and the universe are still being debated. by the brightest and those who think they are the brightest. as a practical day to day experience i would say that gravity is a pretty strong law. as a universal principal, its a strong theory. why is the universe expanding? shouldnt gravity be making it smaller? creationism and evolution both accept the principals and Theories of the universe. one just says that God had a hand in it. id trust the Lord over the theories of man, ha.
  • astronomers, now, say the moon is moving away from the earth. in a few thousand years its supposed to be thousands of miles farther away. what happenned to its gravity? everyone is just guessing, ha.
  • Since all of the details of gravity are not yet entirely understood, it is still just a theory ... certain aspects of its effects here on the surface of the earth have been considered as law because they have been observed and measured and found to be constant, but gravity itself is a mostly unknown and not yet understood force that we have only been able to theorize about.
  • It is sometimes called a theory sometimes a law but strictly speaking our ideas about gravity are theories. Theory is as strong as it gets in science, a theory will never become a fact, facts support theories. Facts are lower in the pecking order so to speak. A fact is something like "Object X took Y seconds to fall when dropped from an elevation of Z metres" All well and good but pretty useless. Once you get a collection of facts you can start to hypothesise (well to be fair you don't need facts first but it usually a good idea) and then test this hypothesis' predictions against more observations. If there is no contradiction you pretty much have a working theory but I hope it is obvious it will never be a fact. A fact is used to check the theory. I was taught that a "law" is just a theory that has hung around until it has become part of the furniture. For example we STILL refer to Newton's work as "Newton's Law Of Gravity" even though it is not a complete nor accurate description of gravity. COnversely we refer to "The Theory of General Relativity" which matches observation far more closely. Science does not "prove" as such. It constructs a model which we then test against observation. Providing there is no conflict then the theory is accepted until it fails. This is no way makes it any less powerful or useful. That's a bit simplistic but in a nutshell that is it.
  • I like Einstein's idea that gravity is the observable effect of how mass warps space. Gravity is the most pervasive force in the universe, because it is produced by all objects which have the property of mass (i.e., galaxies, stars, planets, asteroids, you, me, your cat, and every subatomic particle). Therefore, the gravity produced by all of these "things" extends throughout the universe. That being said, the gravitational field surrounding each mass decreases in strength by the "Inverse Square Law". In other words, if you measure the pull of gravity at some distance D from the center of a massive object (lets say the Earth), and then you measure it at distance 2D, the pull of gravity will have dropped to only 1/4 the strength. If you go ten times further away (10D), the gravitational pull will only be 1/100 of what it was at distance D. Although the gravitational field drops off rather quickly as you move away from a mass (by the time you have moved to distance 1000D the force field will be only 1 one-millionth as powerful), the field produced by each mass will extend everywhere throughout the universe. In essence, every object in the universe is pulling on you right now. Since gravity decreases by the inverse square law, the gravitational field up where the space shuttle orbits is approximately 94% as strong as it is on the surface of the Earth. The reason the Astronauts experience weightlessness is due to the motion of the shuttle itself. The shuttle is in ORBIT, which means that it is essentially falling around the Earth. Due to the tangential velocity of the orbiting shuttle (velocity perpendicular to the direction of the Earth, i.e. at 90 degrees to the Earth), which is about 18,000 miles an hour, the Earth's gravity exerts a pull on the shuttle, which is straight down, but because of the high tangential velocity the shuttle can be thought of missing hitting the Earth. To better understand this idea picture the path of a cannon ball being fired out of a cannon. The cannon balls path is an arch, until it hits the ground that is. Now, picture the cannon ball being fired again, but this time there is a bigger powder charge. The cannon ball still follows an arched path, but this time it is a little smoother than the first time, and it goes further before eventually striking ground. If bigger and bigger charges are put behind the cannon ball eventually it will be moving so fast that as it falls toward the Earth, the Earth's surface will actually be curving away beneath it, and it will miss (and continue to miss) hitting the Earth. Now the cannon ball is in ORBIT around the Earth. If the Earth’s surface were as smooth as a billiard ball (and there was no atmosphere creating energy dissipating friction) it would be possible for an object to be in orbit literally inches away. But you can imagine that the tangential velocity would have to be extremely fast. It would have to be moving fast enough to ensure that the object could travel a great enough distance, where surface curvature would come into play, before falling the few inches to the ground. Likewise, objects orbiting at greater distances require less tangential velocity to balance with the weaker gravity field. A good example of this is the orbital velocity of the planets in our solar system. Mercury, the closest planet to the Sun, has a tangential velocity of about 30 miles per second, Venus – 22 miles/s, Earth – 19 miles/s, Mars – 15 miles/s, Jupiter – 8 miles/s, Saturn – 6 miles/s, Uranus – 4.3 miles/s, Neptune – 3.4 miles/s, and Pluto – 3 miles/s. If the velocity is higher than what would be required to balance with the gravitational field, the object will escape into space. This is an important concept for determining if the expansion of the universe will eventually stop or just slow down, but continue to expand forever. If there is enough mass to “close” the universe it will eventually stop expanding and then go in reverse, resulting in a collapse of everything into a singularity (infinitely small point). This has been called the “Big Crunch” and it is the opposite of the “Big Bang.” I like the idea of the fate of the universe being a “Big Crunch”. It lends to the idea that the universe may pulsate in and out of being, and that it has existed an infinite number of times and will continue to exist an infinite number of times. Extremely fine measurements of universal expansion (galactic velocities and their distances) have pointed to a very puzzling and disturbing result. It appears that the universe will not collapse, and it will not just expand but slow down. What the data indicate is that the expansion of the universe is accelerating, but we don’t understand how this anti-gravitational force is manifested (dark energy?). Therefore, as the universe gets bigger, everything in it is flying apart at an increasing rate. This has lead to a disturbing theory called the “Big Rip”, which says that eventually the expansion of space itself will attain velocities fast enough to rip galaxies apart, then solar systems, then planets, then atoms. The universe will end when everything in it is basically vaporized, never to be again.
  • Don't jump out of a building to test it. :o) I'd say it's as close to a law as science gets.
  • It's Universal Law of Gravitation.When a theory is widely accepted and acknowledged world wide it's known as a Law.
  • Theory. Theory. Theory. Theory. It will always be constantly reformulated to describe it more accurately. Newtonian -> GR -> LQG -> ???
  • The laws pertaining to gravity are but theroies, for we have no idea how gravity works, and if we did we would have vehicles that travelled at light speed.
  • We know that it exists, because anyone can see the force in action, but that's pretty much all we know about it. Heh, they don't call it the "Theory of Gravity" for nothing.
  • Absolute law, anything with mass has gravity.
  • 1) Neither. It is a natural phenomenon. There are various laws *for/of* gravity and theories *for/of* gravity. We are talking here about scientific laws, which are something else than "legal" laws, and about scientific theories, which are a great deal stronger than what many people consider as "just theories". 2) "Gravitation is a natural phenomenon by which objects with mass attract one another. In everyday life, gravitation is most commonly thought of as the agency which lends weight to objects with mass. Gravitation compels dispersed matter to coalesce, thus it accounts for the very existence of the Earth, the Sun, and most of the macroscopic objects in the universe. It is responsible for keeping the Earth and the other planets in their orbits around the Sun; for keeping the Moon in its orbit around the Earth, for the formation of tides; for convection (by which hot fluids rise); for heating the interiors of forming stars and planets to very high temperatures; and for various other phenomena that we observe. Modern physics describes gravitation using the general theory of relativity, in which gravitation is a consequence of the curvature of spacetime which governs the motion of inertial objects. The simpler Newton's law of universal gravitation provides an excellent approximation for most calculations. The terms gravitation and gravity are mostly interchangeable in everyday use, but a distinction may be made in scientific usage. "Gravitation" is a general term describing the phenomenon by which bodies with mass are attracted to one another, while "gravity" refers specifically to the gravitational force exerted by the Earth on objects in its vicinity." Source and further information: http://en.wikipedia.org/wiki/Gravitation Further information: http://en.wikipedia.org/wiki/Theory http://en.wikipedia.org/wiki/Physical_law
  • Like evolution gravity is called a theory mainly for historic purposes. Some time ago a piece of paper was posted around here where I study saying something like this: "Theory is when you know how it works but it still doesn't. Practice is when it works but you don't know why. In this Department [Physics], theory and practice are joined together: nothing works and no one knows why!"
  • That is a great question. I have to take this opportunity to explain something that I witnessed being mistaught repeatedly by former colleagues in high school science classes. HYPOTHESES are proposed explanations for the causes of phenomena (they are NOT "educated guesses" about what will happen---those are called "predictions"). These explanations must be objective. They must either be testable by experimentation or make predictions that can be tested. They must be open to potential refutation and revision. THEORIES are hypotheses that have been so thoroughly tested and confirmed (through experiments designed to disprove them) and so well established that new evidence is not likely to contradict them. The difference between a theory and a hypothesis is the (very large) degree of confidence we have in its validity and power to explain. When someone says: "It's only a theory" they are most likely using the word colloquially and not scientifically. Theories are very powerful explanations that have withstood repeated attempts to dispove them. Nevertheless, theories are still proposed explanations, and all the criteria for a scientific hypothesis still apply. LAWS are statements that describe invariable behavior of things in the natural world. Laws are like predictions that have been confirmed with such uniformity that their contradiction would seem miraculous until new theories are produced to explain the deviation. Laws are usually very succinct and can often be expressed mathematically. Laws are not proposed explanations like hypotheses and theories, but they must still be objective and open to potential refutation. Okay, thanks, I had to do that. Now, as for gravity, there is Newton's Law of Universal Gravitation that describes the attraction between all bodies with mass (see below), and there is Einstein's theory of General Relativity, which explains gravity and, in fact, supercedes the Law of Universal Gravitation in it's scope. So there is a Law of Gravity, and there is a theory that explains it.
  • I think it's a law, law of nature.
  • So far, we only have the law of gravity. We can calculate accelerations, masses, and forces, but we have no cogent theory to tell us WHY gravity works as it does. Although I do have a half dozen or so gravity theories stashed somewhere on my hard drive.
  • It is presumed to be a law right now, because as far as we are in science and technology, we still have not developed an alternate to gravity.
  • Neither, it's a force. There can be theories and/or laws about it.
  • Gravity Is a theory, Science continues to try and explain the unexplainable, but just because it is the best way they can explain it does not make it fact. Think about it, the earth spins over a thousand miles an hour. If any object on earth were to be spun at that rate it would fly off of a given object. The Universe is in a mysterious balance. Therefore in my opinion gravity is a theory.
  • According to the laws of modern sciences, anything, gravity included, is a hypothesis. The fact that things have always been attracted to massive objects doesn't meant that this state of affairs will continue. Of course,gravity has been tested about as frequently as is possible... So, while it's a theory, I wouldn't rely on it failing anytime soon.
  • Gravity is a law. Every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them.
  • A Law.
  • Gravity is a phenomenon, for which we have a theory - first postulated by Newton. +5
  • It's a force.
  • A FACT
  • a theory. We know gravity indeed exists, but we do not know everything about it, and it has been observed to get kinda funky sometimes out there in the universe, not a definite law. But there is a Law of Gravity and that is nothing more than applicable knowledge of gravity's effects on earth.
  • its a force
  • Get a bowling ball, hold it over your head, let go. Then get back to me.
  • Take my word for it, you will go all the way through life and never will need to understand why gravity "sucks". It is more of a "Phenomenon".

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