Olympus Mons 

An impressive view of the Olympus Mons, the largest known volcano in the Solar System (Copyright Calvin J. Hamilton).

Volcanoes are a constant source of wonder. Their sheer fury and destructive power inflicts a combination of awe and terror in all that observe one. The Mauna Loa is by far, the largest volcano on Earth, measuring 6.3 miles (10 kilometers) high and 75 miles (129 kilometers) across. However, it is miniscule compared to the gargantuan giant known as the Olympus Mons which resides on the surface of Mars.

Located in the Tharsis region, this volcano is approximately the same size of the state of Arizona, dimensions measuring 374 miles (624 km) in diameter, 16 miles (25 km) high and is topped by a 4 mile (6 kilometer) high scarp. To top it s the caldera 50 miles (80 kilometers) wide. off, at the summit of Olympus Mons lie. To put all this into perspective, try imagining the entire chain of Hawaiian Islands. That chain could fit inside Olympus Mons with space to spare!

Scientists have studied the physical aspects of Mars in attempts to decipher the cause behind this giant monstrosity. How did this volcano become so large? First, on Mars, the surface gravity is much lower than on Earth. This means that in general, volcanoes can expand and grow up to 100 times the size due to the lesser restriction relative to our planet. Second, the tectonic activity on Mars is dramatically different than that on Earth. On Earth, tectonic plates move in a fashion as to constantly remold and reshape the volcanoes already in existence. That means new volcanoes are formed while old volcanoes are destroyed. On Mars, the crust is much less active and as a result lava piles on itself over and over again, eventually forming one colossal volcano.