Q 01/05

Roughly how often does Halley's Comet return to the inner Solar System?

A) Every 12-15 years

B) Every 74-79 years

C) Every 150-160 years

D) Every 33-36 years

Answer · why

B) Every 74-79 years

The period drifts because Jupiter and Saturn tug on the orbit; it has run anywhere from 72 to 80 years since 240 BC.

Q 02/05

In which year did Halley's Comet last visit the inner Solar System?

A) 1986

B) 1972

C) 1979

D) 1983

Answer · why

A) 1986

It was the worst-placed apparition in 2,000 years, with the comet and Earth on opposite sides of the Sun.

Q 03/05

When is Halley's Comet next expected to reach perihelion?

A) 2038

B) 2049

C) 2054

D) 2061

Answer · why

D) 2061

Perihelion is predicted for 28 July 2061, and this time Earth will be on the same side of the Sun, so the show should be far better than 1986.

Q 04/05

What is the comet's official designation in the periodic-comet catalogue?

A) 109P/Halley

B) 1P/Halley

C) 2P/Halley

D) C/1986 H1

Answer · why

B) 1P/Halley

The 'P' means periodic and the '1' means it was the first periodic comet ever recognised.

Q 05/05

In which year did Edmond Halley publish the work that showed the comet was periodic?

A) 1710

B) 1705

C) 1720

D) 1758

Answer · why

B) 1705

His Synopsis of the Astronomy of Comets used Newton's new laws to compare the comets of 1531, 1607 and 1682.