If we call Gravity a weak force, why does it seem to rule the universe?

Question

I'm hearing that eventually all matter in this universe will become one. Then through a smattering of stuff, a new "bang" occours.

Yep, through the strong force I can stroll on the sidewalk.

Yet, gravity pulls everything together and the theroy suggests, everything will become one.

then bang again.

Is this not the strong force?

I'm thinkin the sidewalk is a whisper compaired to planets crashing.

Or maybe I can't hear the noise?

Answer 1

The scales of the universe are governed by gravity.

The scales of the atomic nucleus are governed by the strong and weak nuclear forces.

When you talk about 'the universe' you imply large scales. When referring to the small scales, you could just as easily ask 'why do the weak an strong forces seem to rule the atom?'.

The reason is that on galactic scales, you are talking about interactions where gravity is king as opposed to small scales where the other forces are king.

The more you magnify, the less influential gravity becomes. Gravity isn't weak in an absolute sense, but it is weak in a scalar comparative sense.

A few corrections - the electromagnetic is what lets you walk on the sidewalk - the repulsion between the electrons in the atoms in the sidewalk and your shoe are more powerful at the scale they interact that gravity is at that scale.

Gravity, in theory, can pull everything together - that's the big crunch theory in a nut shell. Because its relatively weak however,it takes a long time to theoretically make that happen.

Other posters have mentioned other theories, but I thing one has to understand the big bang/crunch before the idea can be 'expanded' further - that's why I don't mention them here - correct as they seem to be from scientific observation. Quantum models of the atom are never going to make sense without first understanding the Rutheford model for instance.

No, its not the strong force - its the point (the big bang/crunch) where all of the forces are indistinguishable from one another. At high enough temperatures and pressures, there is no separation of the fundamental forces. So far, IN THE LAB, the strong, the weak and the electromagnetic have been proven to be different aspects of the same thing that differ only as according to temperature and pressure - gravity is the only hold out.... so far.

The sidewalk as a whisper.... maybe you can't hear the noise....

Perhaps the whisper on the sidewalk is the deafening noise that is the creation of another universe? Perhaps the noise is so loud in that other universe that it is silent in this one?

Answer 2

Gravity is a weak force only in relation to the other forces (electromagnetic, the weak, and the strong force). The electromagnetic force has both positive and negative charges and they average out in large masses. The weak and strong force only work within the nucleus of the atom and have no effect outside of the nucleus. Since gravity has only an attractive force, large masses (planets, stars, etc.) build up the attraction until it is the strongest force in the universe.

But, so far, astronomers have not found enough matter and dark matter to make the universe stop its expansion and contract back into another big bang. As a matter of fact, they have found an anti-gravity energy (dark energy) that works over galactic distances and is making the expansion go faster and faster. So the universe will go on expanding forever.

Answer 3

If understand it right, the strong force is much stronger than the weak force, but is only significant over very short distances, like atomic type distances. Whereas gravity, while weak, extends out to huge interstellar type distances.

As for the universe full of matter piling up into a huge ball, I think it is something like the matter, while held in configuration as best it can by strong force, finally collapses under its own weight. Once you crush an atom out of its shape (you know squash the protons neutrons and electrons all into the middle like sardines) then the strong force is kind of overruled and the gravity continues to add up as your big ball of crap gets denser and denser.

Or maybe you are just thinking of it wrong. I mean if you were at a concert you would probably consider the rock music to be a strong force and the whisper of the person next to you to be a weak force. But if the person next to you happened to be your date, and she whispered 'Let's go get naked in the back of your van', you would suddenly realize that you can't hear the music anymore and all really matters is that whisper. Strong. Weak. It's all relative.

Answer 4

What does it matter whether this specific experiment, which you have imagined, actually has or has not been done? There is a whole theory of gravitation which mathematically predicts all its effects, and every single prediction which could be confirmed by observation, has been confirmed. This theory predicts that your two weights will indeed gravitate towards each other. It is just useless to point to a single impracticable experiment like yours, and claim that the theory is suspect because this experiment is too difficult to perform exactly. If you have a different theory which says that your weights won't gravitate towards each other, then you would need to make other predictions with it too, and test them against the results of experiments which can be set up in the laboratory. That's what the other theorists have been brave enough to do.

Answer 5

Gravity is a weak force because the effects of gravity fall off as the square of the distance between mass entities. Realize gravity is very important because there exists a lot of mass in the universe.

Answer 6

Take a tiny child's toy magnet. touch a nail with it. The whole world is pulling on the nail. The tiny magnet still can lift the nail away from the Earth.
Rub a balloon filled with air on your wool shirt. Touch it to the wall and it sticks. Just a few extra electrons charging the balloon is enough to overcome the force of gravity.
It is not clear that the Universe is ever going to collapse. It is now recognized that we are still accelerating.

Answer 7

The lap top I am lifting to my lap has 6 X 10 ^ 24 metric tons of mass of the earth holding it down. Yet I can lift it with one hand. That is why it is a weak force. A magnet one billionth this size could hold a skyscraper down so hard it would be crushed.

It rules the universe because gravity is instant and effects masses light years away.

Answer 8

I think they say gravity is weak because... Stand up. Jump. Easy right? If gravity were a strong force, like the force that binds atoms, you could never do it.

Answer 9

gravity's a weak force cos it can be easily defied......ever heard of a flying saucer........

Answer 10

no, it is a strong force because it produces an acceleration of 9.8m/s.s