M: what did you do over the weekend? K: I went a global warming rally in London. It was fantastic to be around so many people who care about the environment. M: do you think there's anything we can do to reverse the damage that's been done already? K

发表于:2018-11-30 / 阅读(148) / 评论(0) 分类 生活英语情景口语

Further south still, unstooped, shrouded figures end the flat monotony of the Tundra. This is the tree line, the first place on our journey with sufficient warmth and liquid water to enable a tree to grow。 Surviving here is so crushingly difficult

发表于:2018-12-26 / 阅读(64) / 评论(0) 分类 自然百科2012年

The bison/ form a defensive circle around their young, horns pointing outwards. The wolves need the bison to break rank, but the tables are turning and now the wolves have to retreat. The pack focus their attention on the rear of the herd and the bis

发表于:2018-12-26 / 阅读(60) / 评论(0) 分类 自然百科2012年

As the warm, humid air from the south meets the cold Antarctica, the moisture recurrence crystallizes and snow flakes form from this kind. Each crystal forms around a particle of dust. All have a six folds in the shape, but no two have ever been foun

发表于:2018-12-26 / 阅读(60) / 评论(0) 分类 自然百科2012年

The Taiga forest marks the end of our journey through the Arctic from the frozen ocean down across the lands that surround it The other end of our planet, the Antarctic is starkly different. A frozen continent completely surrounded by ocean. Icebergs

发表于:2018-12-26 / 阅读(54) / 评论(0) 分类 自然百科2012年

And fishing can be dangerous. A southern sea lion. It uses the speed of a breaking wave to catch up with the gentoos. Sea lions normally eat fish. So he is used to catching streamline swimmers. But the gentoos seem more than his match-up at sea. He m

发表于:2018-12-26 / 阅读(56) / 评论(0) 分类 自然百科2012年

The solar system is a hostile place. Earth is under attack from deadly cosmic radiation. Life here is only possible, because it's protected by the magnetosphere, an invisible force field that cocoons the planet. But new evidence reveals that this vit

发表于:2019-01-22 / 阅读(74) / 评论(0) 分类 自然百科2011年

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

发表于:2019-01-22 / 阅读(50) / 评论(0) 分类 自然百科2011年

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 the reversal approaches, the decay of our magnetic field will continue and cosmic radiation will get

发表于:2019-01-22 / 阅读(70) / 评论(0) 分类 自然百科2011年

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

发表于:2019-01-22 / 阅读(69) / 评论(0) 分类 自然百科2011年

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 the North, and release them, and we track them as they try to fly back home. Hes up, OK. Holland wa

发表于:2019-01-22 / 阅读(79) / 评论(0) 分类 自然百科2011年

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. They are actually the recorders of the Earth's magnetic field in hundreds of years, thousands of years

发表于:2019-01-22 / 阅读(80) / 评论(0) 分类 自然百科2011年

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

发表于:2019-01-22 / 阅读(65) / 评论(0) 分类 自然百科2011年

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

发表于:2019-01-22 / 阅读(84) / 评论(0) 分类 自然百科2011年

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 actually reversed polarity. There is a patch on the core in the South Atlantic where things are not poin

发表于:2019-01-22 / 阅读(81) / 评论(0) 分类 自然百科2011年

The randoms of the sea ice are occupied by sun- bathing seals that have been here all winter. But the new arrivals're following the retreating ice edge and they have come here to hunt. Killer whales, the oceans' top predator. Killers are like wolves,

发表于:2019-01-22 / 阅读(71) / 评论(0) 分类 自然百科2012年

Exhausted, it no longer has the energy to pull itself to safety. And the killers are moving in. Game over. Although such team hunts are rarely seen, scientists believe they may be the most complex ever documented in the natural world. They were first

发表于:2019-01-22 / 阅读(54) / 评论(0) 分类 自然百科2012年

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

发表于:2019-01-22 / 阅读(60) / 评论(0) 分类 自然百科2012年

These ice blocks are the size of sky creepers, and this is the bill of more glance with scoten seize man somehow travel on foot. It is one hundred miles long and one of the largest species on earth. Not nothing could prepare those early ex-dollars fo

发表于:2019-02-15 / 阅读(127) / 评论(0) 分类 自然百科2012年

Serious produce server Neser Balwich directs from the front seat while aerial cameraman Mike Calen controls the camera attached to the lows. Above 10,000 feet, the pilot must breathe oxygen through a passed tool beneath the nostrils. Approaching the

发表于:2019-02-15 / 阅读(125) / 评论(0) 分类 自然百科2012年