Is there life outside of Earth?

Watching the film "E.T." and "My Stepmother is an Alien" when I was a kid gave me that idea. "War of the Worlds", "Independence Day", "Star Trek", "Aliens", "Paul", "Star Wars" and the various UFO conspiracies gave me a different viewpoint - the normal views on extraterrestrials. My re-ignited interest in Science and Astronomy, changed that view again. Is there really life elsewhere in the cosmos?

That, I think would be the greatest question being asked by millions of people, for thousands of years. Several documentaries has tackled these questions like Carl Sagans' "Cosmos", Morgan Freeman's "Through the Wormhole", and Stephen Hawking's "Into the Universe with Stephen Hawking".  Though sadly, I have not seen any other documentaries maybe some forgotten titles from National Geographic or Discovery channel but the ones mentioned are the one's I clearly remember.

I think, Science fiction and conspiracy theories greatly contributed to the "belief" that aliens exist, PLUS that these aliens are intelligent, has a very high level of technology, and most of all, almost all of them want to conquer the Earth! I trembled before of these ideas, but I suspended ... or ignored these after I became aware of what the real deal with aliens is.

Since our technology brought us to the moon in 1969, we have been gazing to the stars ever since. Some are active in searching for life using radio waves, and some are using high-tech mobile explorers in Mars to find evidence of life, and some are simply trying to observe life here - specially ones that could survive in extreme environments to determine if there is a possibility that complex biological lifeforms might survive elsewhere in the universe. 

Giordano Bruno

Giordano Bruno (1548 - 1600), first gave the idea that there are infinite worlds populated by intelligent beings. His controversial concept (in a time where anybody who gives an idea contrary to the religious teachings of the Catholic church would mean instant jailtime and possible execution) cost him his life. Other revolutionary thinkers tend to be discreet at that time, fearing for their lives in the process.

The invention of the telescope and the acceptance of the Copernican or the Heliocentric system (where the sun is at the center of the solar system and not earth) are the main ingredients that fueled astronomers to think further and try to answer that question. William Herschel, the person who discovered Uranus is even convinced that the Solar System, as well as other systems are well populated with alien life. 

William Herschel

Even this idea has been endeared with the religious establishment also. The Mormons believe that God has created Earth and all Earth-like planets for humans to live in. Though most mainstream religions does not believe that there are other worlds populated with alien-life as it is their belief that only the Earth is the only planet that was created by God for humans and that our species and life itself is unique in the cosmos. 

Basis for possible life in the Cosmos:

1. That the biochemical components of life which is mainly Carbon-based, is abundant in the Universe. All the elements that make up the human body - mainly Carbon, Oxygen, Hydrogen and Nitrogen are abundant in the Universe, based on observations of the chemistry of stars and galaxies. 

2. That every solar system in the universe has a Goldilocks zone or a Habitable zone - named after the famous story where Goldilocks tried the porridge which is "not too hot, and not too cold". It applies to a region in the solar system where a planet is in a zone where the temperatures is not too hot for water to easily evaporate and where it is not too cold to easily turn it into ice. In our solar system Earth and Mars are considered in this zone. 

3. There is this hypothesis called Panspermia, wherein life on Earth was created by the seeds of extraterrestrial material (meteors, comets) coming from outerspace or from other planets, such as Mars. 

4. Water - an essential component in mixing different chemicals to form simple lifeform, could be found in large quantities in the Solar System. 

5. Extremophiles - organisms that can survive extreme habitats (extreme cold or hot environments) has been discovered and found that these are capable of living in these environments which can simulate extreme environments in outer space. 

There are three major ways to detect extraterrestrial life:

Kepler Space Telescope

1. Kepler Spacecraft - already in space scanning the skies for planets, specially those in the Goldilocks zone. 

SETI Farm

2. SETI - Search for Extra-Terrestrial Intelligence. Uses an array of satellite dishes scanning for radio signals from outer space. 

Curiosity Rover in Mars

3. Robotic Exploration of the Solar System - Either in the form of a space probe (voyager 1 and 2 ) and robot explorers in other planets (notably Mars) like Curiosity. 

So it might take more than our lifetime to determine if aliens exist - even in its primitive simple form. But at least, when the time comes we can truly say.... We are not alone!


Referrence:

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