The Four Fundamental Forces

Have you ever wondered what keeps our atoms from scattering all over the cosmos? What keeps our feet on the ground? What makes those wonderful gadgets and gizmos work? We as common people could only think of answers within our limits of thinking. We can easily say Gravity keeps our feet on the ground and that is correct. Electricity is making all these wonderful machines work and that too is correct. And that's it. We don't know what keep us being, well ... us! If most of the atom is entirely empty space, then why I can see you? Why I can see my monitor? Why I can touch it?

I heard it somewhere that Truth is stranger than fiction. Stranger is the fact that our entire cosmos is "governed" by these invisible forces. Right now there are four fundamental forces that shape us and the Universe as a whole. A force is a push or pull upon an object resulting from the object's interaction with another object. Newton defined a force as anything that caused an object to accelerate -- F = ma, where F is force, m is mass and a is acceleration.What are these so called fundamental forces of nature?

An article from HowStuffworks.com explains it clearly. Here is the link to the article:

http://science.howstuffworks.com/environmental/earth/geophysics/fundamental-forces-of-nature.htm

Currently, there are 4 fundamental forces that have been identified.*

1. Electromagnetic Force
2. Gravitational Force
3. Strong Nuclear Force
4. Weak Nuclear Force

The strong interaction is very strong, but very short-ranged. It acts only over ranges of order 10-13 centimeters and is responsible for holding the nuclei of atoms together. It is basically attractive, but can be effectively repulsive in some circumstances.

The electromagnetic force causes electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It is long-ranged, but much weaker than the strong force. It can be attractive or repulsive, and acts only between pieces of matter carrying electrical charge.

The weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and, as its name indicates, it is very weak.

The gravitational force is weak, but very long ranged. Furthermore, it is always attractive, and acts between any two pieces of matter in the Universe since mass is its source.


Sources:

* http://csep10.phys.utk.edu/astr162/lect/cosmology/forces.html

Further reading:

http://en.wikipedia.org/wiki/Fundamental_interaction

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980127c.html