The Giant of the Solar System: Unveiling Olympus Mons

The Quest for the Largest Volcano

In a recent episode of SciShow Kids, the hosts Jessi and Sam the Bat engage in a fascinating discussion about the largest volcanoes in our solar system. While many might assume Earth holds the record, the conversation quickly shifts to the true champion: Olympus Mons on Mars. Sam highlights that this Martian giant is roughly 100 times larger than the biggest volcano on Earth, Mauna Loa, with a base so expansive that the entire main island chain of Hawaii could fit within its perimeter.

The Role of Plate Tectonics on Earth

To understand why Olympus Mons stands so much taller than Earth’s mountains, the discussion turns to the geological mechanism of plate tectonics. Earth’s outermost layer, the crust, is composed of large, shifting plates. These plates move slowly over the mantle, the Earth's middle layer where rock is so hot that it melts into magma.

Jessi explains that volcanoes like those in Hawaii are formed by hotspots. As a tectonic plate moves over a stationary hotspot, molten rock bubbles up to the surface. Because the plate is constantly in motion, the volcano is eventually dragged away from the magma source, causing it to stop erupting and forming a trail of islands. This movement effectively limits the size of Earth's volcanoes.

Mars: A Stationary Crust and Endless Growth

In contrast, Mars possesses a distinct geological structure. Its crust is not broken into moving plates; instead, it acts as one singular, stationary piece. When a hotspot formed beneath the surface of Mars, the lack of tectonic movement meant that the molten rock remained focused in one location.

Because there was no moving plate to "drag the volcano away" from the magma source, Olympus Mons has been continuously fed by the hotspot for at least 115 million years. This uninterrupted growth has allowed it to reach staggering proportions, standing approximately 26 kilometers high—nearly three times the height of Mount Everest.

Is the Giant Still Alive?

One of the most intriguing questions raised is whether Olympus Mons remains active. While scientists are not entirely certain, there is evidence suggesting it may have last erupted as recently as two million years ago. This possibility leaves the door open for the volcano to continue growing even larger in the future.

A Peak into Outer Space

The episode concludes with a sense of wonder about the scale of this Martian marvel. Olympus Mons is so immense that its peak actually extends through the Martian atmosphere. As Jessi notes, hiking to the top would be truly "out of this world," as the summit effectively reaches into outer space. This exploration of Olympus Mons serves as a powerful reminder of how planetary geology—specifically the presence or absence of plate tectonics—shapes the landscapes of our solar system.