The findings could help us understand the history of other bodies in our solar system
此些研究發現可能有助於人們瞭解，咱們太陽系中，其他天體的演變過程。
The history of our planet has been written, among other things, in the periodic reversal of its magnetic poles. Scientists at the Weizmann Institute of Science propose a new means of reading this historic record: in ice.
與其他事項一樣，咱們行星的演變過程，一直被印記於其磁極的週期性反轉中。以色列魏茨曼科學研究所的科學家們提出了一種，於冰中，讀取此演變過程之記錄的新方法。
Their findings, which were recently reported in Earth and Planetary Science Letters, could lead to a refined probing ice cores and, in the future, might be applied to understanding the magnetic history of other bodies in our solar system, including Mars and Jupiter’s moon Europa.
他們最近(2020年6月)發表於《地球暨行星科學記事》期刊的研究發現，可能引領出精確探測冰芯的方法，且在未來可能被應用來瞭解，我們太陽系中，其他天體的磁演變過程，包括火星及木星的衛星—歐羅巴星。
The idea for investigating a possible connection between ice and Earth’s magnetic history arose far from the source of the planet’s ice – on the sunny isle of Corsica, where Prof. Oded Aharonson of the Institute’s Earth and Planetary Sciences Department, was attending a conference on magnetism.
調查研究冰與地球的磁演變過程間，一種可能關聯性的概念，遠非起自該行星冰的來源。魏茨曼科學研究所地球暨行星科學系教授，Oded Aharonson出席了，位於地中海、陽光普照之科西嘉島上，舉行一項有關磁的會議。
More specifically, the researchers there were discussing the field known as paleo-magnetism, which is mostly studied through flakes magnetic minerals that have been trapped either in rocks or cores drilled through ocean sediments.
更具體地說，在那裡研究人員們討論了，主要是透過一直被陷於岩石或鑿穿海洋沉積物之芯中，薄片狀磁性礦物進行研究，被通稱為古磁性的領域。
Such particles get aligned with the Earth’s magnetic field at the time they are trapped in place, and even millions of years later, researchers can test their magnetic north-south alignment and understand the position of the Earth’s magnetic poles at that distant time.
當這類粒子被陷於原地時，它們會與地球磁場成一直線，即使數百萬年之後，研究人員們能測試它們的南-北磁準線並瞭解地球磁極，在那久遠時期的位置。
The latter is what gave Aharonson the idea: If small amounts of magnetic materials could be sensed in ocean sediments, maybe they could also be found trapped in ice and measured. Some of the ice frozen in the glaciers in places like Greenland or Alaska is many millennia old and is layered like tree rings. Ice cores drilled through these are investigated for signs of such things as planetary warming or ice ages. Why not reversals in the magnetic field as well?
賦予Aharonson上述概念的是後者：在海洋沉積物中，倘若能檢測到少量磁性物質，則或許也能發現並測量，被陷於冰中的它們。一些凍結於類似格陵蘭或阿拉斯加等地之冰川中的冰，有幾千年且如樹的年輪般，是分層的。研究人員們調查研究了，鑿穿上述冰川之冰芯，當行星變暖或冰河時期的此類事態跡象。為何在此磁場中，沒有反轉？
The first question that Aharonson and his student Yuval Grossman who led the project had to ask was whether it was possible that the process in which ice forms in regions near the poles could contain a detectable record of magnetic pole reversals.
領導該項計劃的Aharonson及其學生Yuval Grossman，必需質疑的第一個問題是，在靠近兩極地之地區，於冰形成的過程中，是否可能具有磁極反轉的可偵測記錄。
These randomly-spaced reversals have occurred throughout our planet’s history, fueled by the chaotic motion of the liquid iron dynamo deep in the planet’s core.
此些隨機間隔開的反轉，在咱們行星整個演變過程中，曾經發生過。這是由該行星核心深處之液態鐵發動機的紊亂運轉所激起。
In banded rock formations and layered sediments, researchers measure the magnetic moment – the magnetic north-south orientations – of the magnetic materials in these to reveal the magnetic moment of the Earth’s magnetic field at that time. The scientists thought such magnetic particles could be found in the dust that gets trapped, along with water ice, in glaciers and ice sheets.
在成帶狀岩層及分層的沉積物中，研究人員們測量了，於此些中磁性物質的磁矩(磁的南-北方向)，來揭露在那時期，地球磁場的磁矩。此些科學家們認為，在連同水冰，被陷於冰川及冰原中的塵埃中，能發現這類磁粒子。
The research team built an experimental setup to simulate ice formation such as that in polar glaciers, where dust particles in the atmosphere may even provide the nuclei around which snowflakes form.
該研究團隊建構了一種實驗裝置，來模擬諸如極地冰川中，塵埃粒子於大氣中，甚至可能提供核心，供雪花圍繞形成的冰形成。
The researchers created artificial snowfall by finely grinding ice made from purified water, adding a bit of magnetic dust, and letting it fall though a very cold column that was exposed to a magnetic field, the latter having an orientation controlled by the scientists.
藉由精細研磨，從純淨水製成的冰，添加一點磁性塵埃，然後使其通過曝露於具有，由此些科學家控制之磁場、非常冷的柱子落下，此些研究人員創造了人工降雪。
By maintaining very cold temperatures – around 30 degrees Celsius below zero, they found they could generate miniature “ice cores” in which the snow and dust froze solidly into hard ice.
藉由維持大約零下30℃的極冷溫度，他們發現能形成，雪與塵埃紥實凍結成硬冰的小型“冰芯”。
“If the dust is not affected by an external magnetic field, it will settle in random directions which will cancel each other out,” says Aharonson. “But if a portion of it gets oriented in a particular direction right before the particles freeze in place, the net magnetic moment will be detectible.”
Aharonson宣稱：「倘若塵埃不受外部磁場影響，則會在相互抵消的隨機方向上，穩定下來。不過，倘若在此些粒子凍結到位之前，一部分就朝向特定方向，則淨磁矩會是可檢測的。」
To measure the magnetism of the “ice cores” they had created in the lab, the Weizmann scientists took them to Hebrew University in Jerusalem, to the lab of Prof. Ron Shaar, where a sensitive magnetometer installed there is able to measure the very slightest of magnetic moments. The team found a small, but definitely detectible magnetic moment that matched the magnetic fields applied to their ice samples.
為了測量他們已經，在實驗室中，創造之“冰芯”的磁性。魏茨曼科學研究所的科學家們，將此些冰芯帶到希伯來大學(位於耶路撒冷)，Ron Shaar教授的實驗室。安裝在那裡的靈敏磁力計能測量，最微小的磁矩。該團隊發現了，與施加到其冰樣本之磁場匹配的明確可檢測小磁矩。
“The Earth’s paleo-magnetic history has been studied from the rocky record; reading it in ice cores could reveal additional dimensions, or help assign accurate dates to the other findings in those cores,” says Aharonson. “And we know that the surfaces of Mars and large icy moons like Europa have been exposed to magnetic fields. It would be exciting to look for magnetic field reversals in ice sampled from other bodies in our solar system.”
Aharonson宣稱：「地球古磁性的演變過程，一直從岩石的記錄被研究。讀取在冰芯中的記錄，可能揭露額外的部分，或協助將精確年代歸屬於，在那些芯中的其他研究發現。不過他們知曉，火星及諸如歐羅巴星之大冰冷衛星的表面，一直被暴露於磁場中。在從咱們太陽係其他天體採樣之冰中，找尋磁場反轉會是令人振奮的。」
“We’ve proved it is possible,” he adds. Aharonson has even proposed a research project for a future space mission involving ice core sampling on Mars, and he hopes that this demonstration of the feasibility of measuring such a core will advance the appeal of this proposal.
他附言：「我們已經證實這是可能的。」Aharonson甚至已經為未來涉及，於火星上採集冰芯樣本的太空任務，提出了一項研究計劃。他期盼，這種測量此類冰芯之可行性的證實，將增進此提議的吸引力。
原文網址：https://wis-wander.weizmann.ac.il/earth-sciences/magnetic-history-ice
翻譯：許東榮
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