As we all know that Ttian, one of the moons of Saturn have a potential for life. It is the only moon in our solar system known to possess an atmosphere of any significance.
Ten times thicker than Earth's, Titan's atosphere extends nearly 370 miles(600 kms) above its frigid surface.
It's literal chemical factory, where nitrpgen and methane are zapped by the sun's ultraviolet rays and transformed into organic molecules, some of which descend to the moon's surface while others rise up above the clouds, creating a bluish high-level haze of hydrocarbons.
Cassini's instruments were able to pierce Titan's cloud cover to reveal a world much more Earth-like than moon-like, with weather and rain feeding rivers, streams and lakes all across its surface. In fact Titan is the only place in the solar system where we have discovered liquid on the surface!
The only difference -- and it's a big difference -- is that, 800 million miles away from the warmth of the sun, the liquid on Titan is not water but methane. With temperatures of nearly -300 degrees Fahrenheit water has long since frozen as solid as rock on Titan's surface while methane rains down from the clouds... falling slowly in large drops, methane fills streams and rivers that eventually flow into vast shallow lakes.
Much of the water on Earth may have come from ancient asteroid collisions, according to research by Josep M. Trigo-Rodriguez of the Institute of Space Sciences in Barcelona, Spain, and Javier Martin-Torres at the Center for Astrobiology in Madrid, Spain.
Even though Earth and Titan formed in very different regions of the solar system, where different raw materials were available, they ended up with some of the same elements on their surface and in their atmospheres. These were most likely delivered by asteroids, the pair surmise, as well as by comets to a smaller extent.
During a period known as the Late Heavy Bombardment, between 4.1 and 3.8 billion years ago, water-rich asteroids and comets inundated the inner solar system from the icy outer regions, delivering the water -- and thus oxygen -- to the then-oxygen-poor planet we now call Earth. Other important elements were deposited as well, like carbon, nitrogen and hydrogen. These and other volatile elements became the foundations of our oceans, our atmosphere, and eventually the building blocks of life itself.
Titan, located in the already ice-rich reaches of the solar system, was likewise struck by water-bearing comets and asteroids. Outgassing and accretion by collision helped develop a similar atmosphere on both worlds, the difference being that while Earth's atmosphere eventually evolved into the one that oxygen-breathing animals like insects, dinosaurs, birds and eventually humans could breathe (with the help of mild climates and the existence of liquid water) Titan's chilly temperatures make liquid water impossible, replacing its Earthly role with methane and hydrocarbons.
Now the greatest mystery is "Does Titan really have the potential to support life ?".
We will find out in the years to come...
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