Engravings on Mars' surface rekindle speculations on alien life

Astronomers recently observed ancient engravings on the surface of Mars, which once again sparked the speculations of possibilities of alien life on the "Red" planet.

The "Mars Petroglyph" joins a string of "anomalous" objects like humanoid statue, ball-bearings, a microscopic gearwheel and a thighbone, found among the thousands of images being beamed back by NASA's robotic rovers, Curiosity and Opportunity, News.com.au reported.

The latest "xenoarchaeological" evidence is said to come from an unusual rock caught in a picture from NASA's Mars Curiosity rover earlier in 2014.

The shattered and heavily pixelated piece of rubble appears to be heavily marked with scratches and indentations.