英语听力：探索发现 2014-06-04 BBC 地平线：陨石的真相-10
时间：2019-01-23 作者：英语课 分类：探索与发现2014年
Heset out to investigate a hundred-year-old theory that said asteroids 2 werepowered by the Sun itself. It was called the Yarkovsky effect. The Yarkovskyeffect is a very small acceleration 3 and acts on asteroids and what it is is ifyou take a model, the Sun is hitting the asteroid 1, warming the surface. And asthe asteroid rotates, that hot surface radiates the heat out in a differentdirection into space and that causes an acceleration, a very slightacceleration coming from the photons that were emitted from the asteroid. The ideais that this acceleration, slight as it is, can have significant effects uponthe orbits of asteroids over millions of years.
Itwas an intriguing 4 idea. What sent asteroids out of their orbit and on a pathtowards Earth was photon propulsion. But what was lacking was proof.
TheArecibo telescope is over 300 metres in diameter. It’s one of the most powerfultelescopes in the world and it uses radar 5 to mark the precise position ofobjects in deep space. It was this telescope that would allow Steve Chesley todetect any tiny alterations 6 in the orbit of asteroid Golevka more than 15million kilometres out in space.
Weknew that it would be in one place if the Yarkovsky effect wasn’t acting 7 on it,and it would be over here if it was acting and our models were correct.
WhenSteve and his team studied the data, the results were unequivocal.
- Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
- It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。
- Asteroids,also known as "minor planets",are numerous in the outer space. 小行星，亦称为“小型行星”，在外太空中不计其数。
- Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。
- All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
- He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。
- These discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
- It all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》
- They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
- Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。
- Any alterations should be written in neatly to the left side. 改动部分应书写清晰，插在正文的左侧。 来自《简明英汉词典》
- Gene mutations are alterations in the DNA code. 基因突变是指DNA 密码的改变。 来自《简明英汉词典》