美国有线新闻 CNN 地磁北极在快速由加拿大移向俄罗斯

 

CARL AZUZ: Which of these places is located the farthest north? Anchorage, Alaska, USA; St. Petersburg, Russia; Reykjavik, Iceland; or Oslo, Norway? The northernmost city on this list, that's 64 degrees north latitude¹ is the capital of Iceland.

But they're all in latitudes² north of 55 degrees which means their smart phone maps could be effected by a shift in the magnetic north pole.

There's the True North Pole and the Magnetic North. The True North Pole is geographic³. It's the northernmost point on the planet. The Magnetic North Pole is where compass needles point. Historically, it's been located in the Canadian artic, several hundred miles away from the True north. And it's moving. Scientists say it's always done that slowly. But in recent years, the Magnetic North Pole has been speeding up, traveling about 34 miles per year in the direction of Russia.

Why is this happening? No one knows for sure. Many scientists think it's because the Earth's magnetic field is tied to a liquid outer core deep inside the planet. When the liquid flows, it could pull the Magnetic North with it. Will compasses still point north? For the most part, they will. But this could cause some navigational trouble above 55 degrees north latitude, so for people who live in the cities mentioned in the 10 Second Trivia. What can be done about it? Well there's something called the world magnetic model.

It k?eeps track of the Earth's magnetic poles, and it's used by militaries, North American and European countries and civilian⁴ navigation systems.

Officials usually update it every five years so it can stay accurate. But they just took steps to update it sooner than that, so it can keep up with the faster moving Magnetic North.

1 latitude   

n.纬度，行动或言论的自由(范围)，(pl.)地区

参考例句：

• The latitude of the island is 20 degrees south.该岛的纬度是南纬20度。
• The two cities are at approximately the same latitude.这两个城市差不多位于同一纬度上。

2 latitudes   

纬度

参考例句：

• Latitudes are the lines that go from east to west. 纬线是从东到西的线。
• It was the brief Indian Summer of the high latitudes. 这是高纬度地方的那种短暂的晚秋。

3 geographic   

adj.地理学的，地理的

参考例句：

• The city's success owes much to its geographic position. 这座城市的成功很大程度上归功于它的地理位置。 来自《简明英汉词典》
• Environmental problems pay no heed to these geographic lines. 环境问题并不理会这些地理界限。 来自英汉非文学 - 环境法 - 环境法

4 civilian   

adj.平民的，民用的，民众的

参考例句：

• There is no reliable information about civilian casualties.关于平民的伤亡还没有确凿的信息。
• He resigned his commission to take up a civilian job.他辞去军职而从事平民工作。