Is Olympus Mons really the Solar System’s highest mountain?

Planet Earth possesses many impressively large mountains.

Mount Everest represents the surface’s highest point, peaking 8.849 km (29,032 feet) above sea level.

From base-to-peak, however, many volcanic mountains surpass it, including Mauna Kea, with a dry prominence of 9.33 km (30,610 feet).

Lower-mass planets are less rounded, whereas Earth is the Solar System’s most massive solid-bodied world.

Olympus Mons, also volcanic, rises higher on low-mass Mars: 21.3 km (70,000 feet) as measured by the Mars Orbital Laser Altimeter.

That’s 0.65% of Mars’s radius, as opposed to 0.16% of Earth’s for Mauna Kea.

Even lower-mass worlds possess relatively – and potentially, even absolutely – impressive features.

Jupiter’s moon Io has the tectonic South Boösaule Montes: 1.0% of its radius and 17.5-18.2 km high.

Saturn’s moon Iapetus has an equatorial ridge of unknown origin, 2.7% of its radius, rising 20 km high.

The asteroid Vesta has an impact crater peak, Rheasilvia, rising 8.4% of its radius: 19-25 km, from base-to-summit.

These three latter measurements occurred in 1979, 2004, and 2011, respectively.

Uranus’s and Neptune’s moons, plus all trans-Neptunian objects, remain largely unmapped.

Novel, dedicated missions are required to survey them.

Until that’s done, we cannot conclude whether Olympus Mons is truly the highest.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.

This article is featured on Big Think.