Q 01/05

What causes an aurora?

A) Solar particles hitting atoms in the upper atmosphere

B) Moonlight scattered by high-altitude ice crystals

C) Sunlight reflecting off polar ice

D) Lightning high in the stratosphere

Answer · why

A) Solar particles hitting atoms in the upper atmosphere

Solar particles hitting atoms in the upper atmosphere make the thin gas glow much as electricity lights a neon sign, which is why the biggest displays...

Q 02/05

Why can the northern lights almost never be seen from the Arctic in midsummer?

A) The Sun's particles stop arriving

B) The sky never gets dark enough

C) Warm air absorbs the glow

D) Earth's tilt steers particles away

Answer · why

B) The sky never gets dark enough

The sky never gets dark enough under the midnight sun: the aurora carries on overhead but only shows against a dark sky, and displays tend to peak aro...

Q 03/05

The word 'aurora' comes from the Roman goddess of what?

A) The Moon

B) The night

C) The dawn

D) Fire

Answer · why

C) The dawn

The dawn is what the lights resembled to Europeans far from the Arctic, who usually saw only a faint reddish glow low in the north, as if the Sun were...

Q 04/05

Who is often credited with coining the term 'aurora borealis' in a 1619 treatise published under a pupil's name?

A) René Descartes

B) Tycho Brahe

C) Galileo Galilei

D) Johannes Kepler

Answer · why

C) Galileo Galilei

Galileo Galilei wrongly took the lights for sunlight bouncing off the high atmosphere; Pierre Gassendi, sometimes given the credit instead, used the n...

Q 05/05

Which colour of aurora is the most common?

A) Red

B) Blue

C) Green

D) Purple

Answer · why

C) Green

Green dominates, though often less vividly than photos suggest: long camera exposures record colour in displays that look pale, or even invisible, to ...