A region of ice or other frozen matter surrounding a pole of a planet.
〔天文〕极地冰冠，极冠
Example sentencesExamples
The data will be invaluable in determining the thickness of the planetary crust and charting the seasonal variation in the carbon dioxide ice sheets that make up the Martian polar caps.
While scientists have long believed that the planet's polar caps contain frozen water, the findings were based on indirect evidence from analysis of temperature data or the detection of hydrogen traces.
Previously, surface water ice had been documented on the northern polar cap of Mars, but this is the first time exposed water ice has been documented on the southern polar cap of the solar system's fourth planet.
Up north, at the top of the globe where it is Martian winter, freezing clouds cover the northern polar cap.
As the temperature on Mars increases, carbon dioxide gas will be released from the regolith and the polar cap as it melts (the south polar cap is composed of frozen carbon dioxide and ice).
Definition of polar cap in US English:
polar cap
noun
Astronomy
A region of ice or other frozen matter surrounding a pole of a planet.
〔天文〕极地冰冠，极冠
Example sentencesExamples
While scientists have long believed that the planet's polar caps contain frozen water, the findings were based on indirect evidence from analysis of temperature data or the detection of hydrogen traces.
The data will be invaluable in determining the thickness of the planetary crust and charting the seasonal variation in the carbon dioxide ice sheets that make up the Martian polar caps.
As the temperature on Mars increases, carbon dioxide gas will be released from the regolith and the polar cap as it melts (the south polar cap is composed of frozen carbon dioxide and ice).
Previously, surface water ice had been documented on the northern polar cap of Mars, but this is the first time exposed water ice has been documented on the southern polar cap of the solar system's fourth planet.
Up north, at the top of the globe where it is Martian winter, freezing clouds cover the northern polar cap.