Q 01/05

All the asteroids in the asteroid belt combined have only a few percent of the mass of which body?

A) The Earth

B) The Moon

C) Mercury

D) Pluto

Answer · why

B) The Moon

The Moon is about thirty times heavier than the entire asteroid belt. Ceres alone holds more than a third of the belt's mass.

Q 02/05

On average, roughly how far apart are neighbouring asteroids in the asteroid belt?

A) 10,000 km

B) 100,000 km

C) 1 million km

D) 10 million km

Answer · why

C) 1 million km

About 1 million km of empty space separates one asteroid from the next. Spacecraft cross the belt without having to steer around anything.

Q 03/05

The word asteroid, first proposed in 1802, comes from a Greek word with which meaning?

A) Wandering rock

B) Little planet

C) Star-like

D) Sky stone

Answer · why

C) Star-like

Star-like fitted because even the best telescopes of the day showed the new objects as mere points of light, never as discs.

Q 04/05

Ceres, the largest object in the asteroid belt, has held which official classification since 2006?

A) Dwarf planet

B) Protoplanet

C) Planetesimal

D) Plutoid

Answer · why

A) Dwarf planet

Dwarf planet is the class Ceres shares with Pluto, and Ceres is the only member that orbits in the inner Solar System.

Q 05/05

Which planet's powerful gravity stopped the rocks of the asteroid belt from ever merging into a planet?

A) Saturn

B) Uranus

C) Jupiter

D) Mercury

Answer · why

C) Jupiter

Jupiter stirred the young belt so violently that its rocks smashed apart instead of sticking together. Most of the belt's original material was flung ...