Q 01/05

Many assume the northern summer brings Earth closest to the Sun; in which month is it really nearest?

A) January

B) February

C) October

D) December

Answer · why

A) January

January brings perihelion, Earth's closest approach, in the middle of the northern winter; the seasons come from the tilt of the axis, not from distan...

Q 02/05

Which gas causes about half of Earth's greenhouse effect, more than carbon dioxide?

A) Methane

B) Water vapour

C) Nitrous oxide

D) Fluorocarbons

Answer · why

B) Water vapour

Water vapour does about half the heat-trapping, clouds a quarter and carbon dioxide a fifth, yet it only follows the temperature: warmer air holds mor...

Q 03/05

Which planet's runaway greenhouse effect makes it the hottest in the Solar System?

A) Mercury

B) Venus

C) Mars

D) Jupiter

Answer · why

B) Venus

Venus bakes at about 465 °C under its thick carbon dioxide blanket; Earth's far gentler greenhouse effect is the difference between a 15 °C average an...

Q 04/05

Which continent is so dry that it counts as the world's largest desert?

A) Australia

B) South America

C) Antarctica

D) Asia

Answer · why

C) Antarctica

Antarctica gets its scant moisture almost entirely as snow, yet over millions of years that trickle has built an ice sheet kilometres thick.

Q 05/05

Whose temperature scale first ran backwards, with 0 for boiling water and 100 for freezing?

A) Daniel Fahrenheit

B) Anders Celsius

C) René Réaumur

D) Lord Kelvin

Answer · why

B) Anders Celsius

Anders Celsius proposed his scale in 1742, and within three years it had been turned the right way up, a change credited by some to the botanist Carl ...