英语听力:探索发现 2014-05-28 BBC 地平线:陨石的真相-8(在线收听) |
Well,the early reports are that it is an ordinary chondrite and that means it willbe similar to this one. So this is really exciting for us as scientists becausewe want to know how the planet’s formed, what was around before the planets, whatthe environment was like and how the material that made up the planets firstcame together. And the chondrites are the best way of finding that out. Isthis the most common in the solar system?
Itis the most common type to fall down to Earth. There is almost certainly a biasthat the only material that we get to Earth is stuff that happens to cross theEarth’s orbit. It has to be going in a slightly odd direction to cross theEarth anyway, so there is some kind of selection bias.
Thisis a really special thing for you to kind of have in your career.
Yes,if only something like this would happen in Britain so we could go and get it.
Idon't think there’re too many people watching this programme that will besaying. “I wish it happened in the UK.”
Obviouslysomewhere uninhabited.
Ok.How much of this stuff comes to us every year?
Well,actually, huge amounts. The Earth is growing by about at least 40,000 tons ayear, so a huge amount of material is falling to Earth. But we don’t reallynotice most of it because the vast majority of it comes in the form of dust.
Althoughseveral thousand meteorites actually land on Earth every year, most of thoseactually go unnoticed. They just fall too far away from people. If a meteoritefalls more than maybe 15 feet away from you, you probably won’t notice it. It willmake a dull thud and that will be it, unless it is very large. This event isspecial because it was so huge. There was no way you couldn’t notice thismeteorite falling. It really wanted to get noticed. It said, “Ta-da! I’m here.”Those events are spectacular and they give us scientists these important piecesof rock from which we can learn about the solar system. |
原文地址:http://www.tingroom.com/lesson/yytltsfx/2014/273524.html |