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。