Vesta main content.

Vesta

Part of Hall of Meteorites.

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Between the orbits of Mars and Jupiter there is a wide gap. In the early 1800s, astronomers searching for the “missing” planet in this gap instead discovered smaller objects, which they named asteroids. Today, the known asteroids, including "dwarf planets" Ceres and Vesta, number nearly a million.

Asteroids range from pebble sized to 950 kilometers (590 miles) in diameter. Similar objects were once common throughout the solar system. Most eventually merged into the full-fledged planets, but in the asteroid belt between Jupiter and Mars, Jupiter’s gravitational pull keeps them from combining. The surviving asteroids—and broken pieces that reach Earth as meteorites, such as these samples of Vesta—offer a rare glimpse of the early stages of planet formation.

How do we know: The path to Earth

Although the meteorites in this case were long suspected to have come from Vesta, for many years no one could figure out how they got to Earth. Vesta orbits more than twice as far from the Sun as Earth does—and both orbits are nearly circular, so their paths never come close to crossing. How, then, could a piece of Vesta ever reach Earth?

The mystery was solved when scientists discovered a group of small asteroids whose light signatures showed they were once