It is not widely know that, contrary to the usual explanation given for items falling when we drop them, -especially apples, - gravity is not a downwards pull from beneath, but rather a downwards push from above. 

To prove this, take the example of a person walking in space:-

The person is surrounded by lots of free space which gives the forces of gravity plenty of elbow room to push in towards the middle of that person from all sides, therefore the person remains in relatively the same spot.

Contrast this with the person on the surface of the earth who jumps, but soon falls back to the ground. The reason is that the earth is blocking out the push of gravity from below, so there is an imbalance of pushing forces. The gravity direction which is not blocked, in this case, above, is able to exert a greater influence on the person, therefore they drop back to earth.

Another little known fact is that gravity is repelled by heat. Have you ever wondered why heat rises? It is because heat is a stronger force than gravity, and can readily displace it. This is the reason why you see such huge amounts of fuel being burnt at the launch of a rocket, - to repel the gravity.

Incidentally. light is a visible sign of gravity. You've doubtless read that light is only ever recorded as travelling at 186,000mps. That is true. The problem is not with this observation, but with the fact that most studies ignore the possibility of the force behind the light travelling slower or faster. Light is just a phenomenon which happens to manifest itself only at that speed, and therefore, of course, can only ever be measured at that speed. If it was going faster or slower, it would not be called light, it would be called something else, - gravity.