Is there life in Mars?

Have you ever thought if there's life in other planets? What if we are not alone?
It would be so selfish to think that we are the only kind of life that exist in the universe. So now I'm going to write about a theory that has been around our heads for many years ago: is there life in Mars?

Historical speculations

Since 1877 an Italian astronomer called Giovanni Schiaparelli started to cartography Mars, and he thought he found some thin lines on Mars, something that many people started to discuss about, saying that those lines were actually waterways built by a Martian civilization to carry water from the polar caps to the cities where martians lived.
After that, in 1906 Percival Lowell (an American astronomer) published his book Mars and its Canals.
This theory of a possible Martian civilization allowed H.G. Wells to write The War of the Worlds in 1897.

Similarities between the Earth and Mars

More and more people are thinking that life started in Mars because this planet was so similar to the Earth so many years ago: an atmosphere with oxygen, water and a warm and wet environment, and actually nowadays scientists theorize that the Earth could become a new Mars within thousands of years, when we are almost without oxygen and the extreme temperatures. These similarities allow people to imagine that life existed on Mars and that it even exists now in the form of microorganisms.

Some Mars programs

The Viking program

In 1975, two orbiters called Viking I and Viking II were launched on the rocket Titan III-E. The mission of the Viking program was to search for life and to study the composition of the planet (atmosphere and floor).
The results determined that the main constituent of the atmosphere was carbon dioxide. Also it has a small quantity of nitrogen and oxygen.
It was known that the ground was hard and made by iron, calcium, silicon, aluminium and titanium.
Unfortunately, this mission could not confirm the existence of life in Mars.

The Curiosity Rover

In 2011 the Curiosity Rover was launched and landed on Mars in 2012. This rover has four objectives: determinate if there was ever life on Mars, characterize the weather, determine Mars' geology and prepare for the human exploration of Mars. Let's focus on the first objective. For this, the rover has to determinate and classify the organic carbon components, also, it has to do inventory of the main compounds that permit life: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur and finally, identify the characteristics that represent the effects of possible biologic processes.

Possible life on Mars?

Methane in the atmosphere

In the Earth, most of the methane has a biologic origin, so since we started to explore the space, the methane has been proposed as a life indicator. This is great for us, because in 1999 we detected methane in the Martian atmosphere

Water on Mars !

In July of this year, a group of Italian scientists informed about a subglacial lake on Mars; the first time we have an evidence for a stable body of liquid water. Also, it is estimated that there is 0.01% of water in a gaseous state in the atmosphere.

Finally...

Until today we have not been able to find the final evidence that confirms the existence of life on Mars, but all the evidences point to that in the past there was. Even so, it is thought that currently the planet can contain life, but nevertheless, the existence of habitable conditions doesn't indicate the existence of life.

And... what do you think?

Do you think there is any kind of life on Mars? Or you think that existed a Martian civilization millions of years ago? And a last question... Would you ever travel to Mars in the future? Let me know in the comments!