Mars: Earth's mysterious neighbor that may or may not have once harbored life. The Red Planet's geography certainly suggests water once flowed along the surface, while unexplained spider-like matter have been observed "sun bathing." So now that NASA has its Curiosity rover exploring the barren landscape, what are we hoping to achieve?

Why, to find out if human beings are alone in this universe.

The above video outlines three possible theories regarding life on Mars.

"We're ultimately searching for life on Mars, the possibility that there was ever life on another place in the universe besides Earth," said Dr. Ashwin Vasvada, NASA Deputy Project Scientist for the Curiosity mission. "Mars has always been a fascinating possibility [for life] because it's so close to Earth. The temperature ranges it experiences  are similar to Earth; it often gets above the freezing point, making liquid water possible."

The possible scenarios are pretty fascinating, and pose quite a few questions that man will hopefully one day answer. Curiosity is currently on course to travel to Mt. Sharp, which should give scientists insight into the planet's history through the Mars's multi-layered rock. Studying the layers will ultimately allow people like Vasvada to determine if whether life was possible on Mars or not.

"We probably have gone on Mars from almost an Earth-like world with flowing water and streams and rivers and precipitation, to something planetary wide that's just a dry, barren desert," Vasvada said. Why? We'll see if the planet's layers have the answer.

[via i09]