Q 01/05

The Kuiper Belt extends from Neptune's orbit at 30 AU out to roughly how far from the Sun?

A) About 100 AU

B) About 50 AU

C) About 500 AU

D) About 5 AU

Answer · why

B) About 50 AU

Its inner edge is Neptune's orbit, and the whole thing is about twenty times as wide as the asteroid belt.

Q 02/05

Compared with the asteroid belt, roughly how much wider is the Kuiper Belt?

A) 20 times

B) 2 times

C) 200 times

D) 2,000 times

Answer · why

A) 20 times

It is also somewhere between 20 and 200 times as massive.

Q 03/05

Unlike rocky asteroids, most Kuiper Belt objects are composed largely of what?

A) Frozen ices like methane and water

B) Iron and nickel alloys

C) Silicate rock and dust

D) Solid carbon and graphite

Answer · why

A) Frozen ices like methane and water

At the belt's temperature of only about 50 K, compounds that would be gases nearer the Sun stay frozen solid.

Q 04/05

The belt is named after which Dutch astronomer, who speculated about such a disc in 1951?

A) Willem de Sitter

B) Jan Oort

C) Gerard Kuiper

D) Ejnar Hertzsprung

Answer · why

C) Gerard Kuiper

He is often called the father of modern planetary science, and had eyesight sharp enough to see magnitude 7.5 stars unaided.

Q 05/05

Which Irish army officer and amateur astronomer proposed a disc of bodies beyond Neptune in the 1930s and 1940s, giving the belt its alternative name?

A) William Parsons

B) Kenneth Edgeworth

C) John Dreyer

D) Agnes Clerke

Answer · why

B) Kenneth Edgeworth

He argued the outer solar nebula was too thinly spread to form planets, so it condensed into 'a very large number of comparatively small bodies'.