英语听力:自然百科 金星和水星旅行指南 Venus and Mercury-14(在线收听) |
On earth, Hawaii has some of the most spectacular shield volcanoes that are very similar with the volcanoes we see on Venus. The huge gently sloped volcanoes of Hawaii may be impressive. On Venus there are at least 150 ranging from this size to ten times larger. But the observant visitor may notice that Venus is missing something. The whole impact crater situation on Venus is really very puzzling. With the Magellen images, we see / really a small number/ of impact craters. And such a small number about a thousand. Because we know the rate at which impactors commit it and we can actually date the surface too. Some are between 300 million and 1 billion years old.
Some time/ in the recent geological past, it seems the entire surface of Venus was remodeled. And suddenly (the exploding sound). The surface, geology of Venus is evener than the earth, basically because a lack of water. No water is now lubricating that crust. So you don't get plate tectonics. Instead it seems that happened. It's that forces inside the planet trying to move things around, but it can't. It's locked. And then it explodes: very emissive, globally explosive episodes that happen about every half billion to / billion years. So you would not now want to be on Venus when that happens. Because once something gives way, the whole planet, it might just basically explode/ in a sense and turn/ itself over in a very short matter of time, in geological terms.
Oh, man, look at this. We can see a river of lava beneath the surface. Imagine that this lava is on Venus, probably something very much like this occurs either today or the recent past. No one can say for sure if we will ever see an eruption like this on Venus. No one has ever been able to get this close. |
原文地址:http://www.tingroom.com/lesson/zrbaike/2012/260560.html |