英语听力：探索发现 科学新发现：我们的大气层-7

To discover why these twin planets followed separate paths and to explore what gave us our precious atmosphere, we have to travel back, back four and a half billion years to the birth of the solar system itself. The birth of the solar system created

英语听力：探索发现 科学新发现：我们的大气层-8

Our planet was spared this fate. The magnetic field generated by the Earths core blocked the solar wind, preventing it from blasting away the fragile air. But the Earths atmosphere was still very different from the one we breathe today. It contained

英语听力：探索发现 科学新发现：我们的大气层-9

We were left with this atmosphere made of molten rock and vaporous rock. It took millions of years for that atmosphere to fall out and to be replaced by an atmosphere made up of nitrogen and carbon dioxide and water vapour. These new gases came from

英语听力：探索发现 科学新发现：我们的大气层-10

Evidence of the first oxygen in the atmosphere. The gas was released by a humble microscopic living organism called cyanobacteria. Well it turns out cyanobacteria are the only things that can actually produce oxygen, so we know that at some point cya

英语听力：探索发现 2014-01-19 地平线：什么害死了我们的蜜蜂—26

But there is a second option to find ways of creating more bee-friendly enviornment. There is another reseach group at the University of Reading, who are trying a very different approach. Scientists Vicky and Jenny Wickens are investigating a way to

英语听力：探索发现 2014-01-17 地平线：什么害死了我们的蜜蜂—25

One of the first thing they look at is taking place in the grounds of University of Reading. They are hand-pollinating strawberry plants. It might seem strange, but hand-pollination is something that's already been trying out in southwest China, wher

英语听力：探索发现 2014-01-15 地平线：什么害死了我们的蜜蜂—24

So more than a third of different kinds of bees that once lived in this woodland have now disappeared. What's intriguing here is that their immediate habitat has barely changed.-But what do you think is causing that? If their habitat here is friendly

英语听力：探索发现 2014-01-12 地平线：什么害死了我们的蜜蜂—23

This is good honey. It's very good honey. Yeah, it's very good honey. And this is the honey from the Refuday Tegmoden. Tegmoden,... is not very far, is it? Emnh, now the distance between the hive that produce this and the hive that produce that, how

英语听力：探索发现 2014-01-10 地平线：什么害死了我们的蜜蜂—22

-Hmm, that's pretty lovely.He puts that down to his honey bees' rather unusual habitat. -We're on the roof of Tate Britain and here these are some of the bees that I look after for the Tate. -I have to say and congratulate. You're having really very,

英语听力：探索发现 2014-01-08 地平线：什么害死了我们的蜜蜂—21

This is one of the most important experiments taking place. The one that could help us understand the degree to which research done so far is relevant to bees in the wild.-So what we know so far? There's a good arguement for saying that diseases and

英语听力：探索发现 2014-01-03 地平线：什么害死了我们的蜜蜂—19

That's why I'm heading to south Sussex. I've heard about an experiment happening right now to establish how much pesticide bees are really getting in the wild. So I'm joining in Professor Dave Goulson and his team to find out how they are going to do

英语听力：探索发现 2014-01-01 地平线：什么害死了我们的蜜蜂—18

Lin has recently become R* spokesperson in the neonicotinoid debate.-The big advantage of neonicotinoids is that you can plant the seed already treated. It means the farmer doesn't have to spray. If you've got to spray, it's very expensive. It's got

英语听力：探索发现 科学新发现：我们的大气层-12

Our atmosphere is in constant motion; the moving air that causes our weather circulates between the ground and 50,000 feet. It is the sun that drives this movement. When solar energy reaches earth, it heats the surface and atmosphere, but it does so

英语听力：探索发现 科学新发现：我们的大气层-13

The planet's rotation twists the air as it flows, helping form the hurricanes that lash the coasts. As moist air wells upwards, clouds become electrically charged and send lightning bolts crushing down to the earth, superheating the air to eighteen t

英语听力：探索发现 科学新发现：我们的大气层-14

A single river can carry three times as much water as the entire Mississippi, they provide almost half the annual rain fall for parts of the American Pacific coast, but when they remain in one area for a day or more, they can produce violent flooding

英语听力：探索发现 科学新发现：我们的大气层-15

But to fully forecast the floods, he needs a lot more atmospheric data. He believed robotic drone aircrafts developed for the military could continue to measure the air over the oceans, charting its temperature, wind and humidity. And the flight coul

英语听力：探索发现 科学新发现：我们的大气层-18

The air thins and they begin to lose the protective weight of the miles of air above them. The pressure is dropping, when you finally get to the stratosphere, and to the altitude we like to work at, it's only one one hundredth that of it's on the gro

英语听力：探索发现 科学新发现：我们的大气层-17

You could use the balloons not just to go to the edge of the space as we do now,but go all the way over the line, and actually to use balloons or airships to go all the way into space,space travel without rocket.Officially, the atmosphere ends and sp

英语听力：探索发现 科学新发现：我们的大气层-16

The global average could be up 7 degrees F by the end of the century, wreaking havoc with weather patterns and habitats. We can't prevent climate change by preserving the air's delicate blend of gases, the unique mix that sets earth apart. And our pl

英语听力：探索发现 科学新发现：我们的大气层-21

And above it the fragile air of the mesosphere is shielding us from a another deadly barrage from space. In east Texas, Jeff and Steve are searching for the remains of cosmic missiles that have been shattered by our atmosphere, fragments rarer than d