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  • We tend to think of Mars as a dead planet where all the exciting geologic activity

    我們傾向於認為火星是一個死氣沉沉的星球 所有令人興奮的地質活動都在這裡進行

  • happened billions of years ago. But information from NASA's Mars Reconnaissance Orbiter

    發生在數十億年前。 但來自美國宇航局的火星勘測軌道器的資訊顯示

  • shows us that Mars is still a very dynamic place.

    表明火星仍然是一個非常有活力的地方。

  • Mars has a permanent ice cap made up of water ice at its north pole.

    火星的北極有一個由水冰組成的永久性冰蓋。

  • This pole is ringed by sand dunes, which we're looking straight down on.

    這根柱子被沙丘環抱著,我們'直視著它。

  • These dunes are made of small bits of basalt, dark volcanic rock similar

    這些沙丘是由小塊的玄武岩組成的,深色的火山岩類似於

  • to the rocks found around the Hawaiian volcanoes.

    到夏威夷火山周圍發現的岩石。

  • In the fall and winter, the temperatures are so cold that 30 percent of the Martian carbon

    秋冬時節,氣溫很低,火星上30%的炭

  • dioxide atmosphere freezes onto the ground, forming a seasonal polar cap.

    大氣中的二氧化碳凍結在地面上,形成季節性的極地帽。

  • The ground gets covered with a bright layer of seasonal carbon dioxide ice,

    地面會被一層明亮的季節性二氧化碳冰覆蓋。

  • or 'dry ice,' that's about one to two feet thick.

    或'乾冰,',那'的約一到兩英尺厚。

  • When we flip between images taken at different times in the spring, we can see the dry ice

    當我們翻開春天不同時間拍攝的圖片,我們可以看到乾涸的冰層。

  • cracks form under the sun's heat as the solid carbon dioxide turns into gas.

    在太陽的熱量下,當固體二氧化碳變成氣體時,就會形成裂縫。

  • The gas beneath the ice escapes, carrying dark sand and dust that move,

    冰層下的氣體逸出,帶著黑沙和塵埃移動。

  • as we can see, down the steep sides of the dunes.

    正如我們所看到的,從沙丘的陡峭的兩側下來。

  • We are now looking at different parts of the vast field of dunes. These are called Barchan dunes.

    我們現在看到的是廣闊沙丘領域的不同部分。這些地方被稱為巴昌沙丘。

  • At the start of this time-lapse, the dunes are covered

    在這段延時攝影的開始,沙丘被覆蓋著。

  • with seasonal dry ice so everything is roughly the same color.

    與季節性的乾冰,所以一切的顏色大致相同。

  • The dark streaks and splotches are sand from the dune.

    這些黑色的條紋和斑點是沙丘上的沙子。

  • There are small splotches of sand at the crest of the dune. Then we start seeing the ice crack.

    沙丘的山頂上有一些小沙點。然後我們開始看到冰裂縫。

  • Sand is pushed to the top of the ice layer by the escaping gas outlining the cracks.

    沙子被逸出的氣體推到冰層頂部,勾勒出裂縫。

  • As time goes on, the cracks widen and fresh bright frost condenses in the vicinity.

    隨著時間的推移,裂縫擴大,附近凝結出新的明霜。

  • Now, we see sand coming from the crest of the dune and sliding down the steep dune slopes.

    現在,我們看到沙子從沙丘的山峰上冒出來,從陡峭的沙丘坡上滑下來。

  • A ferocious wind has picked up, blowing sand and dust across the dune.

    起了一陣狂風,吹得沙丘上沙塵四起。

  • Until the dark sand dune is free of seasonal ice. Let's watch that whole sequence again.

    直到黑暗的沙丘上沒有季節性的冰塊。 讓我們'再看一遍這整個序列。

  • We start with ice-covered dunes in the early Spring.

    我們從初春的冰雪覆蓋的沙丘開始。

  • Some areas of the ice rupture and crack, allowing sand and dust to escape along with the escaping gas.

    有些地方的冰層破裂開來,讓沙塵和逸出的氣體一起逸出。

  • The gas from the dry ice destabilizes the slopes, reshaping the dunes.

    乾冰產生的氣體破壞了山坡的穩定性,重塑了沙丘的形狀。

  • This activity happens every Spring in the vast dune fields of the Martian polar regions.

    這種活動每年春天都會發生在火星極地的廣闊沙丘地帶。

  • These are not the sort of events that would naturally occurs on Earth. Mars may look

    這些都不是地球上會自然發生的事件。火星可能看起來

  • Earth-like, but in some ways it is a very different planet from our own.

    類似於地球,但在某些方面它與我們的星球截然不同。

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