polar cap

American  

noun

1. Geology. the icecap situated at either end of the earth's poles.

2. Astronomy. either of the two bright areas around the poles of the planet Mars, consisting of water ice and frozen carbon dioxide.

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polar cap Scientific  

1. The mass of ice that covers either of the Earth's polar regions year-round.

2. The mass of frozen carbon dioxide and water that covers either of Mars's polar regions.

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Etymology

Origin of polar cap

First recorded in 1890–95

Example Sentences

The polar cap appears to become more prominent when the planet's pole begins to point toward the Sun, as it approaches solstice and receives more sunlight.

From Science Daily • Dec. 19, 2023

They note that there are several bright storms visible both near and below the southern border of the polar cap.

From Salon • Dec. 19, 2023

Scientists can use that data to extrapolate how much heat might be rising from beneath the south polar cap, melting the ice and creating more potential lakes.

From Nature • Jul. 24, 2018

Topping off this strange image is a distinctly red polar cap, of unknown composition.

From Textbooks • Oct. 13, 2016

No blue sea would be lapping the shores of Barrow; instead the Arctic Ocean would be a roaring white cauldron forming ice that would join the land with the polar cap.

From "Julie of the Wolves" by Jean Craighead George