Q 01/05

Sunlight crosses some 150 million kilometers to reach Earth, a trip that takes roughly how long?

A) About 8 seconds

B) About 8 minutes

C) About 8 hours

D) About 8 days

Answer · why

B) About 8 minutes

About 8 minutes pass between light leaving the Sun and landing on Earth, so the Sun in the sky is always the Sun as it was that long ago.

Q 02/05

Albert Einstein won his 1921 Nobel Prize for work on which topic, rather than for relativity?

A) Brownian motion

B) Quantum entanglement

C) Photoelectric effect

D) Mass-energy equivalence

Answer · why

C) Photoelectric effect

Photoelectric effect research earned the prize: light striking a metal knocks electrons loose, which Einstein explained in 1905 by treating light as t...

Q 03/05

On a phone or TV screen, which color appears where red and green light overlap at full strength?

A) Brown

B) Purple

C) Gray

D) Yellow

Answer · why

D) Yellow

Yellow appears because colored lights add together instead of muddying like paint. Screens use the same trick to build every shade from only red, gree...

Q 04/05

Which illusion makes a hot road ahead look wet, as if a pool of water were lying on it?

A) Mirage

B) Halo

C) Sun dog

D) Aurora

Answer · why

A) Mirage

Mirage comes from a Latin word meaning to look at or wonder at. The shimmering water is really an image of the sky, bent toward the eye by hot air nea...

Q 05/05

Stars twinkle when viewed from the ground because their light is disturbed on its way through what?

A) Interstellar dust clouds

B) The asteroid belt

C) Earth's magnetic field

D) Earth's atmosphere

Answer · why

D) Earth's atmosphere

Earth's atmosphere is turbulent, and its shifting pockets of air nudge a star's pinpoint of light around. Planets are near enough not to be such tiny ...