Olympus Mons is a large volcanic mountain on which planet?

Mars.

Olympus Mons is a massive volcanic mountain located on Mars, the fourth planet from the Sun in our solar system. It holds the title of the tallest planetary mountain in the solar system, standing at a staggering height of approximately 22 kilometers (13.6 miles) above the surrounding plains. To put its size in perspective, Olympus Mons is nearly three times the height of Mount Everest, which is Earth’s tallest mountain above sea level.

The base of Olympus Mons spans about 600 kilometers (373 miles) in diameter, comparable to the size of the state of Arizona. Its immense size is supported by the lower gravity of Mars, which is about 38% of Earth’s, allowing geological structures to reach heights that would be unsustainable under Earth’s stronger gravitational force.

Olympus Mons is classified as a shield volcano, a type of volcano usually built almost entirely of fluid lava flows. It is characterized by its low slope angles; its shallow inclines are reminiscent of a warrior’s shield. The lava that forms Olympus Mons is basaltic, meaning it has a low viscosity, allowing it to flow smoothly and spread widely across great distances. This composition contributes to the volcano’s layered, broad profile.

The age of Olympus Mons is estimated to be about 200 million years, and it might still be an active volcano, though there are no confirmed observations of activity in the recent past. Its last lava flows are suspected to be relatively young in geological terms, possibly only a few million years old.

The sheer size and uniqueness of Olympus Mons make it an object of significant interest not only to planetary geologists but also to the broader scientific community interested in volcanic and planetary formation processes. Understanding Olympus Mons and Martian volcanism contributes valuable insights into the geologic activity and history of Mars and offers a comparative platform against volcanic features on Earth and other planetary bodies.