Name: 這張地圖可以提供缺失的線索，說明火星如何變得不適合人類居住
Uploaded: 2020-08-06T08:45:12.000Z
Duration: 5 min 2 s

情態助動詞 (推斷語氣)

You may have heard that Mars doesn't have a magnetic field. But that's not true!

你可能聽說過，火星沒有磁場。但這不是真的!

Now, thanks to data from NASA's MAVEN satellite,

現在，由於美國宇航局MAVEN衛星的數據。

researchers at the University of Colorado, Boulder

科羅拉多大學博爾德分校的研究人員。

have created the very first detailed map of the electric currents responsible for shaping

繪製了第一張詳細的電流圖，該圖負責塑造

the magnetic field that wraps around Mars.

Not only are the visualizations stunning,

but they provide clues of how we can make this inhospitable planet one we can live on...maybe.

但它們提供了線索，告訴我們如何讓這個荒涼的星球成為我們可以生活的地方......也許。

Let's start with what we know so far. The region of space around a planet that's

讓我們從目前所知的情況開始。一個星球周圍的空間區域是：

dominated by that planet's magnetic field is known as its magnetosphere.

由該行星的磁場所主導，稱為其磁層。

Earth's magnetosphere is driven by an internal dynamo,

地球的磁層是由內部的發電機驅動的。

a rotating mass of molten iron that's located in our planet's outer core.

一團旋轉的熔融鐵，位於我們星球的外核。

The energy generated by the rising, cooling, and sinking of that molten iron

那塊熔鐵的上升、冷卻和下沉所產生的能量。

gets converted into a powerful magnetic field, which shields Earth from

轉化為強大的磁場，保護地球不受汙染。

the charged particles of solar and cosmic radiation and protects our atmosphere.

太陽和宇宙輻射的帶電粒子，保護我們的大氣層。

Unlike Earth, Mars doesn't have a dynamo — and as a result, no intrinsic magnetic field

與地球不同的是，火星沒有發電機--是以，也沒有內在的磁場

to stop charged particles from stripping away its atmosphere.

以阻止帶電粒子剝離其大氣層。

Turn back the clock to about 4.3 billion years ago and Mars might have looked a lot more Earth-like.

把時間撥回到大約43億年前，火星可能看起來更像地球。

It had a thick atmosphere and warm climate

capable of sustaining bodies of water like rivers, lakes, and even oceans!

能夠養活江河湖泊甚至海洋等水體!

All of this would have been possible if Mars once had a working dynamo  of its own to protect its atmosphere.

如果火星曾經有一個自己工作的發電機來保護它的大氣層，這一切都會成為可能。

But somehow, Mars transformed from a warm and wet place

但不知怎的，火星從一個溫暖潮溼的地方變成了

變成了一片寒冷、荒涼的沙漠。

There are a couple of leading theories as to what might have caused this dramatic transformation.

關於是什麼原因導致了這種戲劇性的轉變，有幾種主要的理論。

Some scientists believe that a series of giant asteroid impacts bombarded Mars over a period

一些科學家認為，在一段時期內，一系列巨大的小行星撞擊轟擊了火星。

of 100 million years. The idea goes that these impacts overheated the planet's mantle

一億年的時間認為這些撞擊使地球的地幔過熱了

and stopped the dynamo, effectively killing off the planet's intrinsic magnetic field.

並停止了發電機，有效地殺死了地球的固有磁場。

Certain evidence suggests that Mars might have had a dynamo in only a single hemisphere.

某些證據表明，火星可能只在一個半球有一個發電機。

And in fact, missions to the red planet have found remnants of a stronger magnetic field

而事實上，前往紅色星球的任務已經發現了更強的磁場的殘餘物

With a lopsided energy field, the planet's atmosphere

隨著能量場的傾斜，行星的大氣層也在發生變化

would have been left vulnerable to erosion from the solar wind,

allowing it to collide with atoms in the upper atmosphere and eject them into space through a process

讓它與高層大氣中的原子相撞，並通過一個過程將它們彈射到太空。

As its atmospheric gas was slowly stripped away,

隨著其大氣中的氣體被慢慢剝離。

Mars' atmosphere eventually became depleted enough to transform the planet into a cold, arid place.

火星的大氣層最終變得枯竭，足以讓這個星球變成一個寒冷、乾旱的地方。

Today, signs of Mars' ancient intrinsic magnetic field still exist.

如今，火星古老的固有磁場的跡象依然存在。

Since 2018, NASA's InSight lander has been on the ground measuring the strength and direction

自2018年以來，NASA的InSight著陸器一直在地面上測量強度和方向。

of the planet's magnetic field and collecting detailed measurements of magnetic fields in the crust.

的行星磁場，並收集地殼中磁場的詳細測量結果。

Because most of the rocks at Mars' surface

are too young to have been magnetized by the planet's former field, scientists speculate

科學家們推測，由於太過年輕，不可能被星球以前的磁場磁化。

that the sources of these crustal magnetic fields are rocks buried deep underground.

這些地殼磁場的來源是埋在地下深處的岩石。

Located anywhere from a couple of hundred meters to several kilometers below the ground,

位於地下幾百米到幾公里的地方。

these older rocks formed before the planet's dynamo shut down and remain magnetized,

這些較老的岩石形成於行星的發電機關閉之前，並保持磁化。

acting as local mini-magnetospheres today.

By combining the measurements collected by InSight with satellite data,

通過將InSight收集的測量數據與衛星數據相結合。

researchers hope to identify exactly which rocks carry magnetism

研究人員希望能確定到底是哪些岩石帶有磁性

While on the ground, InSight has also recorded

mysterious fluctuations in the strength and direction of the magnetic field between day and night.

晝夜之間磁場強度和方向的神祕波動。

Here's how it works. The charged particles that make up the solar wind are

下面是它的工作原理。組成太陽風的帶電粒子是：

highly conductive, inducing electric currents that shape how energy flows into Mars' atmosphere.

高導電性，誘發電流，形成能量如何流入火星的大氣層。

These currents cause a 'pile-up' of the magnetic field in the planet's upper atmosphere,

這些電流會導致地球上層大氣的磁場 "堆積"。

until they become strong enough to create an induced magnetosphere.

直到它們強大到足以形成一個誘導磁層。

By analyzing five years of data from MAVEN, researchers were able to piece together the

通過分析MAVEN五年來的數據，研究人員能夠拼湊出MAVEN的數據。

electric current systems in Mars' atmosphere.

The initial results show how these electric currents

初步結果顯示，這些電流是如何產生的？

interact with the solar wind, causing it to wrap around the planet and form an induced

與太陽風相互作用，使其環繞地球，形成誘導的

magnetosphere that offers Mars some protection.

磁層，為火星提供一定的保護。

Because while MAVEN and other previous missions

因為雖然MAVEN和其他以前的任務

have seen hints of these currents before, this is the first time we've been able to map the complete circuit.

之前已經看到了這些電流的提示，這是我們第一次能夠繪製完整的電路。

MAVEN's goal is to explore the upper atmosphere,

and it's not alone. Along with five other current Mars missions,

而且它並不孤單。隨著目前其他五個火星任務。

it's trying to understand the potential for life to exist on Mars.

它試圖瞭解生命在火星上存在的可能性。

If we ever plan to put boots down on the red planet,

如果我們打算在紅色星球上放下靴子。

we'll need to understand how important a magnetic field is for regulating climate.

我們需要了解磁場對調節氣候有多重要。

Because while this work won't bring back Mars' thick atmosphere,

因為雖然這項工作不會讓火星的濃厚大氣層重現。

it may help us determine if Mars ever hosted life and if it could again.

它可能會幫助我們確定火星是否曾經有生命存在，以及是否會再次出現。

Mars isn't the only misfit without an intrinsic magnetic field.

火星並不是唯一一個沒有固有磁場的不適應者。

If you wish you had an interplanetary zip code of your own,

如果你希望自己有一個屬於自己的星際郵編。

why not check out this video on terraforming Venus and Mars!

為什麼不看看這個關於金星和火星梯田化的視頻呢？

Is there any cool space phenomena you'd like to see us cover?

有什麼酷炫的太空現象你想看到我們報道嗎？

讓我們在下面的評論中知道下來。

Make sure to subscribe and thanks so much for watching.

一定要訂閱，非常感謝您的觀看。