polar cap


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polar cap

[′pō·lər ‚kap]
(astronomy)
Any of the bright areas covering the poles of Mars, believed to be composed of frozen carbon dioxide and water-ice.
(hydrology)
An ice sheet centered at one of the poles of the earth.
References in periodicals archive ?
Mars tips its northern hemisphere far into our view from now through September, exposing the North Polar Cap as the cap shrinks through the Martian northern hemisphere's late spring and summer.
Perhaps it's the Earth-like character of this distant world that captivates us--its clouds and seasons, ever-changing polar caps, or its vast deserts with their unpredictable dust storms.
His drawing of May 8 in poor seeing shows little detail except polar cap and collar; a much better view on May 18 definitely shows the fading.
There may be a whole mass of water ice underneath the southern polar cap.
As the polar cap retreated, observers reported numerous rifts and streaks on its surface.
London, Nov 13 (ANI): An infrared camera aboard NASA's Cassini spacecraft has discovered a unique aurora lighting up Saturn's polar cap, which is unlike any other known in our solar system.
Some may have evaporated into space or migrated to the much smaller southern polar cap, and a substantial amount may have seeped underground.
The seasonal North Polar Cloud Hood has been clearing off as spring advances in Mars's northern hemisphere, allowing the brighter, sharper North Polar Cap to show through.
This opposition will also present observers with an ideal opportunity to record the recession of the North Polar Cap (NPC).
These lines of evidence, he adds, may also explain a long- standing puzzle: Why is Mars' north polar cap so much larger than the south cap?
The bright area of the northern polar cap halos the top of the planet.