Gravity? How does that work exactly? Does Gravity sort of pull everything toward the center of the Earth?

Question

Why are larger things sometimes lighter than smaller things? It looks like the gravity would have more room to grasp and pull on the larger thing so it would be heaver. How exactly does that work anyway? I only ask on the Christian page because someone on here was comparing it to evolution a minute ago.

Answer 1

It isn't just "sort of", it's exactly correct. The size has nothing to do with it, it is only the mass that counts. Since mass is typically determined by weighing, it would seem that this is a tautology, but it is not: mass is the resistance to acceleration, and if measured by that means, could in principle be different from the mass as measured against gravity. But careful measurements show that the two aspects of mass are the same.

As for evolution, it's now a proven fact.

Answer 2

It's.. complicated... and not entirely understood, even by those who study it. Yes, earth's gravity does pull everything towards the center. If a larger thing weights less than a small thing, it's because the smaller thing is more dense. Even though it may not look like it, the smaller, denser object is made up of more material than the larger one. Think of foam, for example. It may be a big block of foam, but it's not entirely solid, there's a lot of empty space. Not as much total matter as there would be in the same size block made of metal, or wood. The same reason a hollow rubber ball weighs less than a solid rubber ball of the same size. There's simply more stuff in the solid one, even though they are the same size. Gravity doesn't only work on the outside surface of an object, it works all throughout it.

Answer 3

Well exactly how it works really needs a lot of work. Gravity is a very weird thing and we understand evolution a lot better. We have a pretty good model describing the motion of it. But exactly how it pulls is a huge issue in physics.

Einstein said it is the effect of matter moving through time. And then he settled on a geometric model where he says that it bends the fabric of space into the time dimension. That is as good an explanation as you are going to get without a lot of reading.

Answer 4

I have been Studying Anti-Gravity for a While.

There is an Interesting THEORY that goes sorta like this:
In the Invisible Realm Around us (sub-Atomic) there are Particles that Flow like a River from "UP Above all Around" down to the center of the Earth (360 degrees) Pulling Everything Down with the Flow. Where they go when they get to the Center of the Earth is What I am Interested in.
What ya Think?
No, it is not my Theory. But, there Seems to be some Truth there somewhere.
Ditto............

Answer 5

Gravity is proportional to the mass of an object, all mass distorts the space time continuum! The more massive an object the more it curves the space time continuum, this is especially noticeable around massive objects like black holes, which curves space so much it actually slows time down!

Momof2 I'm sorry to burst your bubble but bigger things are NOT NECESSARILY less dense, look at black holes they are much bigger than our sun AND much more massive!

Macguyver, you are probably talking about gravitons I'm sorry to burst your bubble but gravitons are NOT sub atomic particles but virtual massless particles that can be calculated but have not been proven to exist yet!

g_carillo13, excellent answer! I gave you a thumb up:)

And yes everything tends to fall to the center of gravity of a mass, that is why , marbles roll down a hill, and if you dug a hole to the center of the earth you could fall in:)

Answer 6

There are two forces in nature that we experience every day: gravity and magnetism. You may have magnets on your refrigerator, and you know that a magnet will attract a refrigerator with a certain amount of force. The force depends on the strength of the magnet and the distance between the magnet and the metal. You also know that magnets have two poles -- north and south. Either pole will attract iron or steel equally well, north will attract south, and like poles will repel one another.

Gravity is the other common force. Newton was the first person to study it seriously, and he came up with the law of universal gravitation:

Each particle of matter attracts every other particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
The standard formula for gravity is:

Gravitational force = (G * m1 * m2) / (d2)
where G is the gravitational constant, m1 and m2 are the masses of the two objects for which you are calculating the force, and d is the distance between the centers of gravity of the two masses.

G has the value of 6.67 x 10E-8 dyne * cm2/gm2. That means that if you put two 1-gram objects 1 centimeter apart from one another, they will attract each other with the force of 6.67 x 10E-8 dyne. A dyne is equal to about 0.001 gram weight, meaning that if you have a dyne of force available, it can lift 0.001 grams in Earth's gravitational field. So 6.67 x 10E-8 dyne is a miniscule force. When you deal with massive bodies like the Earth, however, which has a mass of 6E+24 kilograms, it adds up to a rather powerful force. It is also interesting to think about the fact that every atom attracts every other atom in the universe in some small way!

Einstein later came along and redefined gravity, so there are now two models -- Newtonian and Einsteinian. Einsteinian gravitational theory has features that allow it to predict the motion of light around very massive objects and several other interesting phenomena. According to Encyclopedia Britannica:

The general theory of relativity addresses the problem of gravity and that of nonuniform, or accelerated, motion. In one of his famous thought-experiments, Einstein showed that it is not possible to distinguish between an inertial frame of reference in a gravitational field and an accelerated frame of reference. That is, an observer in a closed space capsule who found himself pressing down on his seat could not tell whether he and the capsule were at rest in a gravitational field, or whether he and the capsule were undergoing acceleration. From this principle of equivalence, Einstein moved to a geometric interpretation of gravitation. The presence of mass or concentrated energy causes a local curvature in the space-time continuum. This curvature is such that the inertial paths of bodies are no longer straight lines but some form of curved (orbital) path, and this acceleration is what is called gravitation.
If certain assumptions and simplifications are made, Einstein's equations handle Newtonian gravity as a subset.
The question of why atoms attract one another is still not understood. The goal is to combine gravity, electromagnetism and strong and weak nuclear forces into a single unified theory. (Check out the quantum gravity string theory.)

Answer 7

Larger things can be lighter than smaller things when they're less dense. And you'll find that, without wind resistance, both objects will fall at the same rate.

Answer 8

Actually gravity is a relatively weak force comparatively to other forces like magnetism and inertia. Some Physicist think that it is not actually a force in this universe but actually an overlapping force from a parallel universe and there is actually strong mathematics that support it.

Answer 9

Gravity is determined by mass. Bigger things that are less dense are lighter and have less gravitational pull. Gravity pulls masses toward each other's center. There are other forces that keep things from just being pulled into each other.

Answer 10

It's only a "theory" - don't worry about it.

The bible teaches us that the Earth is a round flat disk floating on and surrounded by water. We don't need "gravity" to keep us from falling off. How heavy something is depends on how god created it. Why would the Earth pulling on something make it heavier? The "theory of gravity" makes no sense. Read your bible. That's all you need to know.