Gravity may not be just what you think it to be. It's concept has being wrongly described to many. Lets correct our views now by considering this brief but very informative article, You will be thrilled by what gravity really is.
The word gravity is one of the most popular scientific word to the non scientific minds. However, its concept is not clearly understood even by some science oriented persons. Now let clear things up.
What really is the true concept of gravity?
We all know that matter has mass and occupies space, but the this concept we know is kind of incomplete. According to laws of gravitation by sir Issac newton, every matter (mass) has another important property. Every matter tends to attract every other matter in the universe with force. This force of attraction between masses in the universe is known as gravitational force.
Does masses on earth attract themselves?
Yes they do. Gravitational interactions do not simply exist
between the earth and other objects; and not simply between the sun and
other planets. Gravitational interactions exist between all objects
with an intensity that is directly proportional to the product of their
masses. So as you sit in your seat in the physics classroom, you are
gravitationally attracted to your lab partner, to the desk you are
working at, and even to your physics book. Newton's revolutionary idea
was that gravity is universal - ALL objects attract in proportion to the
product of their masses. Gravity is universal. Of course, most
gravitational forces are so minimal to be noticed. Gravitational forces
are only recognizable as the masses of objects become large
So why don't we notice it?
The reason is simply explain by considering the Newton's law of gravitation and the law of relativity.
The law of gravitation states that two masses in the universe will attract themselves with a gravitational force that is proportional to the product of their masses, m , but inversely proportional to the square of the distance between them, r.
,
- F is the force between the masses, in Newtons N
- G is the gravitational constant, G is approximately equal to 6.674×10−11 N m2 kg−2
- m1 is the first mass, in kg
- m2 is the second mass, also in kg and
- r is the distance between the centers of the masses in meters m
From this we can see that the higher the interacting masses, m1 ans m2, the higher the gravitational force between them. How does this affect gravitation on earth?
Its the reason why the attracting forces between masses on earth is not so showy. From the above universal gravitational equation, we can deduces that masses on earth are too small in magnitude to have a tangible gravitational pull on themselves.
According to the idea of relativity, we are told that in the presence of two or more vectors the sum total of the apparent vector to be experienced would most likely make the lesser vectors seem as if they do not exist.
To illustrate, imagine two cars driving side by side with d same velocity. To observers in both cars it would feel as if both cars are not moving. However, if one car seem to be moving with a higher velocity then it wide seem as if the other is not moving even though it is moving. Such is the case with the gravity on a body due to the earth compared to that due to any other body. The mass of the earth is way bigger so shows a much more gravitational pull compared to that of other bodies, as such overshadows all other gravitational force base on relativity.
Why does the moon experience the earths gravity even when astronauts in space that are far closer to the earth are already feeling weightless due to negligible gravitational pull on them by the earth mass?
From the gravitational equation, this is because, compared with the distance apart r, the mass of the astronaut, m2 is very small hence would product a very insignificantly small gravitational pull. However the mass of the moon is very great and hence produce a very large gravitational interaction with the earth's mass even though it is at a far farther distance from the earth.
Questions to ponder over
- Why do masses on the moon experience lesser gravitational pull than on earth?
- Would you experience greater gravitational pull in Jupiter than on earth?
- What other laws do you know that describes the effect of universal gravity?
- How does gravity accounts for the behavior of black hole?
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