英语魔法游戏：保卫地球的超人

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英语听力：自然百科 冰冻星球 前往地球尽头—3

A male polar bear is searching for a mate. Willing females are few and far between. And the sea ice some of which he travels will soon melt and vanished. He's running out of time to find the mate in this frost frozen desert. Ten miles ahead, a single

英语听力：自然百科 冰冻星球 前往地球尽头—2

I am standing at the North Pole, the very top of the earth. Up here, it's easy to see why the Polar Regions are so cold. The sun never rises high enough in the sky to warm my back. And those rays that do strike the surface are mostly reflected back f

万花筒 2009-06-14&06-15 地球将如何毁灭？

French researchers are predicting doom for Planet Earth. They believe neighboring planets could stray out of orbit and collide with the Earth billions of years from now. The BBC's David Shukman explains their theory. A view of Earth from orbit and a

英语听力：自然百科 冰冻星球 前往地球尽头—4

Few have witnessed this moment, for the male, his only tender encounter in an otherwise solitary life. But it doesn't last long. A rival suitor has also caught the female's scent. Courtship has to be put on hold. He must fight for his rights. He sees

英语听力：自然百科 冰冻星球 前往地球尽头—5

It's time for the couple to go their separate ways. She will give birth to his cubs alone in nine months time. And he may never see her again. He returns to the frozen ocean, no doubt relieved to resume his solitary ways. And just in time, the ice be

英语听力：自然百科 冰冻星球 前往地球尽头—6

For those who can get here in summer, these waters provide a feast of epic proportions. But the good times will be very short, a problem that faces all life in the Polar Regions. Journeying the south across the Arctic Ocean, the first land you/ reach

英语听力：自然百科 冰冻星球 前往地球尽头—7

This, Jakobshavn Isbrae, is the fastest flowing glacier on our planet, moving as much as 14 meters a day. As it advances, it destroys everything in its path, even cutting its way through Greenland's great mountain ranges on its drive downwards toward

英语听力：自然百科 地球力场 Earth's Force Field—2

Radiation causes damage at the most fundamental level. It mutates the blueprint of life, DNA. Earth's magnetosphere is our crucial defense. It's so fundamental to our evolution and continued existence that the race is on to understand why it's changi

英语听力：自然百科 地球力场 Earth's Force Field—16

During its magnetic cycle, the Sun undergoes periodic changes in activity. Every 11 years, it enters solar maximum. This 11 years cycle of solar activity has peaks where theres lots of solar storms. And right now where the sun is taking a little napp

英语听力：自然百科 地球力场 Earth's Force Field—12

Six years later, they come to believe these light flashes are the results of high energy, heavy cosmic rays penetrating the spacecraft and the crew members' eyes. These/ protons or electrons, just very, very high energy, ripped / part of atoms, sprin

英语听力：自然百科 地球力场 Earth's Force Field—15

By analyzing thousands of lava samples, geophysicists discover/ that the Earth's magnetic field has reversed over 18,000 times in the last 20 million years. On either side of these reversals is a long period of dramatically reduced field strength. Du

英语听力：自然百科 地球力场 Earth's Force Field—5

If we could flip a switch and just turn off the Earth's magnetic field, it will take about 15,000 years to disappear, based on the rate of decay of the field that we've seen over the last 150 years. It's currently decaying at a rate that would see an

英语听力：自然百科 地球力场 Earth's Force Field—3

In polar regions where the magnetic field is / weakest, auroras glow in the sky. These dazzling displays of colored lights form when solar particles slam into gases in our atmosphere causing them to glow. The stronger the solar wind, the more dramati

英语听力：自然百科 地球力场 Earth's Force Field—4

Scientists believe that the South Atlantic Anomaly, is a sign of a global decline in the magnetic field. Evidence of this comes from a surprising source. Dr. Mimi Hill uses pottery to uncover the secrets of earth's magnetic past. Ancient pots tell us

英语听力：自然百科 地球力场 Earth's Force Field—8

Easily confused by this idea, there has a big thawed iron inner core, so that I think it's just the bar magnet, just permanent magnet frozen in nad, and that's where causes all the magnetic field. But it's too hot inside the Earth, that can't happen

英语听力：自然百科 冰冻星球 前往地球尽头—16

The seal is now what the killer wanted, but the hunt is far from over. They need to wrap their prey by the tail while avoiding its snapping jaws. Only them will they be able to pull it down and drown it. Side swipes create farther underwater turbulen

英语听力：自然百科 冰冻星球 前往地球尽头—19

They were travelling on foot and their first sight of this mountains must have been daunting indeed. In front of them stretched one of the world's longest ranges, spanning two thousand miles from one side of the continent to the other. The winds uphi

英语听力：自然百科 冰冻星球 前往地球尽头—23

Youve got these beautiful clear glass-like pillars and right next to it, its really delicate. Look at in them, filament is there. As the cave team explore deeper, each chamber reveals ice crystals more strange and spectacular than the last. No one on

英语听力：自然百科 冰冻星球 前往地球尽头—24

End of the run. No! Ive got him coming out, I just didnt get him going back in. All right! Below the sea ice, the dive team is setting up an underwater studio. Using a rang of waterproof lights and time-lapse cameras, they hope to capture the growth