Uranus rolls around the sun on its side, so each pole spends decades in light and then in dark.

What it means

Its axis is tipped by about ninety eight degrees, essentially lying in the plane of its orbit. Since a year there runs to eighty four Earth years, each pole gets roughly forty two years of continuous sunlight followed by the same span of darkness. The usual explanation is a collision with something Earth-sized during the formation of the solar system, though the evidence is indirect.

The claim comes from NASA.

Nearby in the collection

The facts either side of this one.

• NASAhard, 77 letters
• NASAeasy, 72 letters
• NASAeasy, 73 letters
• NASAmedium, 79 letters

About as hard as this one

Scored closest to it by the model behind our guide to solving cryptograms.

• NASA · Imagine the Universeeasy, 70 letters
• NASA · Imagine the Universeeasy, 69 letters
• NASAeasy, 67 letters
• NASAeasy, 90 letters