NASA’s Mars Reconnaissance Orbiter (MRO) successfully captured a picture of an avalanche on the surface of Mars in May this year. Scientists pointed out that when the sun was shining on the north pole of Mars at that time, the temperature would cause the snow to melt, and it was very normal for avalanches to occur.
red dust cloud
Through NASA’s High Resolution Imaging Science Experiment (HiRISE), the outside world saw for the first time that loose ice on Mars fell from a 500-meter cliff, and red dust was raised from the terrain below. The place where it happened was 370 kilometers from the north pole of Mars. In this regard, Dr. Candy Hansen, a scientist at the University of Arizona (University of Arizona), explained: “Every spring, the sun shines on the sedimentary rocks in the north pole of Mars. The temperature will destabilize the ice and loosen the ice.”
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好發於春季
火星偵察軌道衛星捕捉到該畫面時正位於 318 公里高度，解析度每畫素 32 公分。雖然捕捉到雪崩並不常見，但極地冰冠融化相當正常。因為火星季節長度是地球的 2 倍，而且從 3 月開始，火星北半球正處於春季，要等到 10 月 8 日夏至報到後才會結束。
除了春季等溫暖季節容易讓火星出現雪崩外， 2018 年 6 月， NASA 也捕捉到小行星撞擊火星而造成雪崩。 NASA 指出，撞擊火星的小行星直徑只有 5 公尺，並留下小型撞擊坑。由於小行星墜落在斜坡而讓後者不穩定，於是產生土與塵交雜的雪崩。
資料來源：
Carpineti, A. (2019). NASA Captures The Incredible Moment An Avalanche Happened On Mars. [online] IFLScience. Monz, I. (2019). NASA Mars Orbiter Captures Stunning Avalanche On Red Planet As Ice, Blocks Destabilize. [online] International Business Times.
