Do Aliens Exist?

There are billions of Galaxies in the universe. Each Galaxy has billions of stars. Many of the stars have planets orbiting around them. It is a most possible thing that many of the planets may have life on it. Many planets may have most advanced form of creatures on them, like Man on the earth. Many people think that It is possible that such advanced life forms travel in the space and some of them visit our Earth. It sounds interesting, but why they should visit our Earth when their are many other planets everywhere in the universe to visit?

The simple definition of Aliens is the creatures which are not originated from our Earth. It is most possible thing that life on other planets in the universe exists. The life on other planets would be very different from that of our Earth. There may be most advanced and most complex form of life at other places. Further, many planets in the universe may have creatures with highly advanced intellect and technology.

According to Frank Drake, an American astronomer and astrophysicist who is well known for his research in extraterrestrial intelligence, there are at least 1000 civilizations in our own Galaxy, i.e. the Milky Way. He extends the number to 1 billion civilizations on the maximum side.

Remember that there are 200 billions stars in Milky Way and this number may increase to 500 billions. You can imagine how many planets would be there. There must be a large number of planets with an environment suitable to give birth to various forms of life in Milky Way. Further, our universe is very vast and contains a large number of Galaxies. We are able to see only a small fraction of the universe even through most powerful and most advanced telescopes. According to the latest estimates, there are about 500 billion Galaxies. Each Galaxy consist billions of stars and many of the stars have planets orbiting them.

So we can not claim that life exist only on our planet. It is logical to think that life exists on at least 1 Percent of the planets in the Universe. Some of the life forms on many planets must have advanced intellect and technology.

Now the question arises. Do the Aliens visit our Earth? Many people think that Aliens visit our Earth. This has been a very popular subject for Hollywood movies and Science fiction writers. But there are many flaws in thinking that Aliens visit our Earth.

It is almost impossible thing for Aliens from other planetary systems to visit our Earth, even if they have developed most advanced technology to travel in the space. Here are the reasons:

1. We know, nothing can travel faster than light. We know that light travels at the speed of 300000 Kilo Meters per second. The distances between stars are very large. The closest star to our Earth is Proxima Centauri. The distance between our Sun and Proxima Centauri is 4.3 Light Years. That means the distance traveled by light in 4.3 years at the speed of 300000 Kilometers per second.

2.There are 72 stars within a radius of 17 light years from our Sun. Only 4 of these seventy two stars have planets orbiting around them. There is no sign of existence technically advanced life form on these planets. It is logical to think that technically advanced creatures use Radio Waves for communications. We have not observed existence of radio waves spread from these planets.

3. Even if there are technologically advanced creatures on the planets beyond the the closest stars, it is more difficult and time consuming for them to visit our Solar System. Obviously, they will prefer to visit nearby planets of their own planetary system, or the planetary systems of nearby stars.

4. Forget about the Aliens from other Galaxies, it is impossible for them to visit other Galaxies, even for the most advanced creatures. Remember that in the history of mankind, man is yet unable to go beyond the Moon physically. Moon is just 350000 to 400000 Kilo Meters away from us. The Light distance between Earth and Moon is just 1 to 1.3 Light Seconds. Now think about the Light Year Distances... 4.3 years, 100 years, 1000 years and even Millions of years.

5. It is ridiculous to think that Aliens visit our Earth for shelter as their own planet is in danger, or just to attack our Earth. In first case, they will take shelter on planets nearby to them. In second case, there is nothing special in Earth or human beings to choose them to attack.