文章列表

• 1.英语听力：自然百科 穿越银河系的旅行 Through Milky Way—1
• We live amongst 200 billion stars, in the Milky Way galaxy, a vast cosmic city. The earth is located in a quiet neighborhood, in a safe neck of the wo...
• 2.英语听力：自然百科 地球力场 Earth's Force Field—19
• As the reversal approaches, the decay of our magnetic field will continue and cosmic radiation will get increasingly close to the Earth's surface. As ...
• 3.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...
• 4.英语听力：自然百科 地球力场 Earth's Force Field—17
• We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. We drive them about 20 miles away to...
• 5.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 activ...
• 6.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 ...
• 7.英语听力：自然百科 地球力场 Earth's Force Field—14
• By analyzing different samples of lava, Herrero / Bervera has built up a picture of how the filed has changed since long before humans were around. Th...
• 8.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 ...
• 9.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 me...
• 10.英语听力：自然百科 地球力场 Earth's Force Field—11
• Blockson's computer model reveals that at the South Atlantic Anomaly, the magnetic field isn't just weaker than anywhere else on the planet. It's actu...