英语听力：自然百科 金星和水星旅行指南 Venus and Mercury-5

 Mercury's core makes up about 60% of the planet by mass. It's about twice as big as earth. Why would it have such a huge core for such a small planet? Some people think there was a huge impact.

 

Kind of stripped off a lot of the planet and now what we were seeing is just the remnants of a once bigger planet. Many questions about Mercury remain unanswered, questions a new mission will hopefully solve/.

 

Five, four, three, main engine start, 

 

two, one and zero and liftoff of Messager on NASA's mission to Mercury. 

 

NASA's Messenger Spacecraft will become the first probe to orbit / Mercury. Getting a spacecraft into orbit around Mercury is difficult for two reasons, the sun and the size, the sun as the source of heat and the sun as the source of gravity. To slip past the sun, Messenger/ taking a convoluted¹ route, flying past the earth once, Venus twice and Mercury itself three times to arrive in full- time orbit by 2011. 

 

When you get into orbit, you can end up mapping the whole planet at fairly high resolution. So we will start having a mature and fundamental understanding of Mercury not only its surface, but its whole chemistry throughout the all planet. From that we can unravel² to some degree how it formed. What other secrets are edged into Mercury's ancient surface. Already Messenger has sent back some curious clues. Arriving in Mercury, there's a list of natural wonders to see, and even a dazzling light show.

1 convoluted   

adj.旋绕的；复杂的

参考例句：

• The snake slithered through a convoluted path.蛇在羊肠小道上爬行。
• The policy is so convoluted even college presidents are confused.这项政策太令人费解，甚至连大学校长们也是一头雾水。

2 unravel   

v.弄清楚（秘密）；拆开，解开，松开

参考例句：

• He was good with his hands and could unravel a knot or untangle yarn that others wouldn't even attempt.他的手很灵巧，其他人甚至都不敢尝试的一些难解的绳结或缠在一起的纱线，他都能解开。
• This is the attitude that led him to unravel a mystery that long puzzled Chinese historians.正是这种态度使他解决了长期以来使中国历史学家们大惑不解的谜。