Across our solar system, towering geological formations capture our imagination, none more so than Earth’s Mount Everest and Mars’s Olympus Mons. These iconic peaks represent the highest points on their respective planets, sparking curiosity about their immense scales. A direct comparison of their heights reveals fascinating insights into the distinct planetary processes that shaped them, highlighting the unique geological conditions of Earth and Mars.
Olympus Mons: A Martian Giant
Olympus Mons is a colossal shield volcano on Mars, recognized as the largest known volcano and tallest mountain in the solar system. It rises approximately 21.9 to 26 kilometers (about 13.6 to 16 miles) above the surrounding plains, with a base spanning roughly 600 kilometers (370 miles) across.
Its immense size is primarily due to Mars’s lack of active plate tectonics. Without moving plates, a stationary hotspot continuously fed lava to the same location for billions of years, allowing the volcano to build to extraordinary height and width.
Lower Martian gravity (about 38% of Earth’s) also played a significant role, allowing volcanic material to accumulate to greater heights before collapsing. The thinner Martian atmosphere contributes to less erosion from wind and weather, preserving these massive structures over geological timescales. Olympus Mons also has a very gentle average slope of only about 5%.
Mount Everest: Earth’s Apex
Mount Everest, Earth’s highest mountain, stands at an elevation of 8,848.86 meters (29,031.7 feet) above sea level. Located in the Mahalangur Himal sub-range of the Himalayas, its summit forms part of the border between China and Nepal.
Its formation is a direct consequence of Earth’s dynamic plate tectonics, specifically the collision between the Indian and Eurasian plates. This process began approximately 50 million years ago, causing the Earth’s crust to crumple, fold, and uplift, creating the vast Himalayan range.
While plate tectonics uplift mountains, other Earthly processes limit their ultimate height. Active erosion from wind, water, and glaciers constantly wears down mountain peaks.
Earth’s stronger gravity also restricts how tall mountains can grow before the rock deforms or collapses under its own weight. These factors ensure that mountains on Earth cannot reach the scale of formations found on less active planets.
The Scale of Difference
When comparing Olympus Mons to Mount Everest, the Martian giant is substantially taller. Olympus Mons rises approximately 22 kilometers (13.6 miles) above the Martian surface, making it about 2.5 times the elevation of Mount Everest above sea level. Olympus Mons has a vertical relief of over 21 kilometers from its base to its peak, while Everest’s height from its base to summit is considerably less.
This vast disparity highlights the fundamental geological differences between Earth and Mars. Mars’s lack of active plate tectonics, lower gravitational pull, and minimal atmospheric erosion allowed Olympus Mons to grow to immense proportions. In contrast, Earth’s dynamic plate tectonics, stronger gravity, and active erosional processes limit the height of its mountains.