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  3. Northern lights is the name of a light phenomenon often seen in the northern regions. The lights have been around since Earth fo

Northern lights is the name of a light phenomenon often seen in the northern regions. The lights have been around since Earth fo

admin2021-10-20  92
问题     Northern lights is the name of a light phenomenon often seen in the northern regions. The lights have been around since Earth formed an atmosphere—the dinosaurs saw it, early humans saw it and our descendants will see it. The scientific name for the phenomenon is "Aurora Borealis", aurora for short.
An aurora is a sporadic, generally faint, atmospheric phenomenon usually seen in the night sky from locations at high latitudes. More commonly known as the "northern lights," it may first appear as a faint, milky glow low in the north, too dim for the human eye to detect any color but bright enough to silhouette clouds near the horizon. It may develop into steady greenish arcs or form glaring, swirling curtains of yellow-green light. During the most dramatic displays visible from regions at middle latitudes, such as central Europe and the United States, a crimson glow fills much of the sky. It was this form that inspired European scientists of the 1600s to call the phenomenon aurora borealis, literally "northern dawn," but it also occurs at high southern latitudes, where it is formally called aurora australis, "southern dawn." The same processes are at work in both hemispheres—not just on Earth, but on other planets as well—and today, scientists simply refer to this phenomenon as an aurora. The ghostly forms of an aurora include quiescent patches, veils, and arcs, and rapidly moving rays and curtains.
    Many historical accounts of the northern lights from areas far south of its usual location exist. An early Chinese record describes it as a "red cloud spreading all over the sky." The Roman philosopher Seneca wrote that an aurora in A.D. 37 tricked the emperor into sending troops to aid what he thought was the burning seaport of Ostia, "when the glowing of the sky lasted through a great part of the night, shining dimly like a vast and smoking fire." In 1583, similar "fires in the air" mobilized thousands of French pilgrims, who prayed to avert the wrath of God. On September 15, 1839, an intense aurora dispatched firefighters throughout London.
    What causes the showers of charged particles that create the northern lights? Ultimately, the source lies in the solar wind, a fast-moving stream of particles constantly flowing from the Sun that carries the Sun’s magnetic field out into space. The solar wind, typically moving at 250 miles (400 kilometers) per second, flows past Earth’s magnetic field and molds it into an elongated bubble or cavity, compressing its sunward side and stretching its night side far beyond the Moon’s orbit. Under certain conditions, the solar wind’s magnetic field can merge with Earth’s, creating electrical currents that drive protons and electrons into the polar atmosphere. Powerful events occurring on the Sun can drive enormous changes in the solar wind, increasing both its speed and density and enhancing its effect on Earth.
It has been recorded that once in France, the northern lights were believed to be _______.
选项 A、a fire set by the enemy troops
B、punishment to humans by God
C、crimes which would enrage God
D、an indication of the doomsday
答案B
解析 第3段倒数第2句中的the wrath of God常表示“上帝的怒火”，wrath通常暗示上帝因为愤怒而要惩罚世人，由此可见，本题应选B。本题最具干扰性的是D，doomsday是“世界末日”的意思，从原文的wrath可以知道上帝将要惩罚世人，但以什么方式惩罚却是不明确的，D说得过于绝对了。
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