SSS 2008-08-26

This is Scientific American's 60-Second Science. I'm Adam Hinterthuer. Got a minute? Don't be fooled by those big bovine eyes and the mouth slowly chewing cudcows have a magnetic personality. At least thats the claim made by German researchers in the

VOA常速英语2015--科学家研究地球磁场

科学家研究地球磁场 WASHINGTON Most of us hardly ever think about the Earth's magnetic field. We might be aware that it helps guide birds as they migrate and ensures that our compasses point north, but not realize that it is one of the crucia

VOA标准英语2015--马里兰大学实验室复刻地球磁场

Scientists Take on Earths Magnetic Field 马里兰大学实验室复刻地球磁场 WASHINGTON Most of us hardly ever think about the Earth's magnetic field. We might be aware that it helps guide birds as they migrate and ensures that our compasses p

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—18

Earth's magnetic field has reversed thousands of times since its formation 4.5 billion years ago. And scientists now believe that the next reversal is imminent. The race is on to predicting exactly when it will occur. In 2010, the European Space Agen

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—13

Glatsmire's model shows that the magnetic poles swap places spontaneously due to / complex processes within the core. We were used to the idea that a compass points somewhere near the North Pole and hence we can use it for navigation, but there are p

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—6

It's clear from the fact that the Martian crust is strongly magnetized, that there must have been a magnetic field on Mars in the past, that the only way we know to magnetize rocks is for them to form in the presence of magnetic field. Why did Mars l

英语听力：自然百科 地球力场 Earth's Force Field—7

The loss of the magnetic field has a catastrophic impact on the planet's evolution. Mars becomes the red planet we see today. If earths magnetic protection continues to fade, would it suffer the same fate? If it vanishes completely, the planet might

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 地球力场 Earth's Force Field—9

As the vast sphere reaches / maximum speed, something incredible happens. Huge lines of magnetism arc in and out of the model core. Well, we can't see the magnetic field coming out of the experiment, we can measure them, we can put many different mag

英语听力：自然百科 地球力场 Earth's Force Field—10

Larry Newitt from the Geological Survey of Canada charts the movement of the magnetic North Pole as it wanders the icy reaches of northern Canada. To determine where the magnetic pole / is, we can't rely on one single observation. What I try to do is

Magnetic Bubbles Detected at Edge of Solar System

The latest data from the twin Voyager spacecrafts suggest the outer edge of the solar system is not smooth but filled with giant magnetic bubbles. Scientists say the turbulent bubbles are the result of the interaction between the Suns magnetic field

【英语时差8,16】录像机如何记录（下）

But heres a mystery: When you press pause on the VCR, the screen doesnt go blank. Instead, you get a frozen image. Remember, you need a changing magnetic signal to create even a still video image. If the video tape isnt moving, where is this changing

英语听力文摘 English Digest 257、录像机工作原理

How Your VCR holds a Note VCR-盒式磁带录像机VCR是Video Cassette Recorder的缩写盒式磁带录像机。就功能上而言，它是使用空白录像带并加载录像机进行影像的录制及存储的监控系统设备。VCR作为许多晚会