Before starting today's video, I want to ask you a question: Do you remember how high is the highest mountain you have climbed? We will always choose the first king among all kinds of geographical scenery: the deepest lake, the longest river, and of course the highest mountain.

As early as 1715, the Tibetan people found a golden tower-shaped peak in the Himalayas later named Zhu-Mulangba. After multiple surveys the peak's altitude was determined to be 8,848.86 meters—the world's highest mountain.

Since Earth's highest peak reaches over 8,000 meters, are there taller mountains elsewhere in the solar system? Let's explore Mars. Observations and spacecraft imagery revealed Olympus Mons, a huge volcano whose summit reaches into Martian atmosphere. Its height exceeds 21,000 meters by some measures.

Mars' lower gravity (~38% of Earth's), lack of plate tectonics, and reduced erosion allow volcanoes to grow much taller than on Earth. The Tharsis plateau hosts Olympus Mons and several other enormous volcanoes.

Shield volcanoes like Olympus Mons form from low-viscosity lava that can flow long distances, producing gentle slopes but enormous volumes. On Earth, plate motion spreads volcanic activity over different locations, preventing a single edifice from reaching Olympus-scale heights. Mars' stationary crust allowed repeated eruptions over the same hotspot for hundreds of millions of years.

Volcanic plumbing systems, magma supply rate, and the thermal history of the mantle all contribute to the final shape and size of these edifices. Numerical models indicate that prolonged, high-volume eruptions combined with minimal erosive forces permit edifices to accumulate vertically to greater heights on Mars.

Comparing volcanic provinces across terrestrial planets (Mercury, Venus, Earth, Mars) reveals how gravity, atmosphere, crustal thickness, and internal heat budget shape surface expression. Venus, for example, has widespread volcanism but a dense atmosphere that modifies morphology, while Earth shows plate-bound volcanoes with distinct stratovolcano composition.

Studying Mars' giant volcanoes helps calibrate models used for exoplanet interpretation: differences in radius, mass, and composition can imply strikingly different surface geology for rocky worlds around other stars.

Orbital radar, spectrometry, and high-resolution imaging (e.g., from Mars Reconnaissance Orbiter) catalog flow morphologies, lava compositions inferred from thermal inertia, and crater counts that constrain relative ages. These datasets reveal a sequence of eruptive episodes, collapse features, and signs of flank instability that tell a detailed story of edifice growth and modification.

Understanding Martian volcanism informs landing-site selection for rovers and sample-return missions. Ancient lava flows may preserve records of early interior chemistry, and sheltered lava tubes could be prime targets for future human habitats due to radiation shielding.

Future in-situ dating of Martian samples will be critical to pin down eruption timelines and test hypotheses about prolonged volcanic activity versus episodic bursts.

Olympus Mons and the Tharsis province illustrate how planetary parameters drive geological extremes. These features are natural laboratories for understanding volcanic construction, planetary thermal evolution, and how environments diverge even among similar rocky worlds.

As we plan exploration and potential human missions, the lessons from Mars' monumental volcanoes underscore the value of comparative geology in unraveling planetary histories.