By Nadia Drake
NANTES, France — Vesta might be a planetary runt, but it holds bragging rights to one of the solar system’s highest peaks.
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Rising 20 kilometers from the floor of an enormous impact basin in the asteroid’s south pole, Vesta’s massif is taller than Hawaii’s Mauna Kea — Earth’s highest mountain when measured from the bottom of the ocean. Vesta’s peak is still smaller than the solar system’s reigning giant, a Martian volcano called Olympus Mons. But then, Vesta is only 530 kilometers in diameter to Mars’ 6,800 kilometers. Scientists haven’t named the protrusion yet, but the crater is named Rheasilvia, after the mythological mother of the twins who founded Rome.
Chris Russell, principal investigator of NASA’s Dawn mission, says he now considers Vesta the smallest terrestrial planet in the solar system. “Like Earth, Mars, Venus and Mercury, Vesta has an ancient basaltic crust, lava flows going across the surface, and it also has a large iron core,” he says. “It has tectonic features, like on Earth: rift valleys, ridges, cliffs, hills and a giant mountain.”