美国有线新闻 CNN 8月16日小行星与地球擦肩 但NASA未能提前发现

What is the term for a space rock that enters Earth's atmosphere and hits the ground? Meteor, meteoroid, meteorite¹, or meteoroid? Meteoroids become meteors when they enter our atmosphere and meteorites² when they hit the ground.

以下哪个是进入地球大气层并撞向地面的太空岩石的术语？流星、流星体、陨石还是陨星体？流星进入地球大气层时会变成流星，撞击地面时变成陨石。

Just like meteoroids are relatively³ small rocks that are zipping around in space, asteroids⁵ are bigger ones and two of those have been in the news recently. The first one passed very close by Earth on August 16th. It was about the size of a car and scientists say it probably wouldn't have hurt anyone if it had entered our atmosphere. But NASA missed it. The agency didn't pick up on the asteroid⁴ until after it had whizzed by less than 2,000 miles away. And researchers say that makes it the closest asteroid ever known to pass by Earth and not hit it.

流星体是在太空中快速移动的相对较小的岩石，而小行星是更大一些的岩石，其中两颗小行星近日出现在新闻中。第一颗小行星在8月16日与地球擦肩而过。其大小与小汽车差不多，科学家表示，即使其进入地球大气层，可能也不会造成任何伤害。但美国国家航空航天局（简称NASA）未观测到这颗小行星。该机构直到小行星飞到距地球2000多英里处时才发现它。研究人员表示，这是目前已知距离地球最近但并未发生撞击的小行星。

NASA didn't miss another asteroid that's headed our way. This one's about six and a half feet in diameter and should zip by on November 2nd. Scientists say the chance of this rock hitting Earth is about 4/10 of 1%. They don't expect it to have a major impact or to disrupt the U.S. election the next day.

美国国家航空航天局没有错过另一颗逼近地球的小行星。这颗小行星的直径约为6.5英尺，应该会在11月2日与地球擦肩而过。科学家表示，这颗小行星撞击地球的几率约为0.4%。他们预计这不会产生重大影响也不会干扰第二天的美国大选。

1 meteorite   

n.陨石；流星

参考例句：

• The meteorite in Jilin Exhibition Hall is believed to be the largest in the world.吉林展览馆的陨石被认为是世界上最大的。
• The famous Murchison meteorite smashed into the Australian ground in 1969.1969年著名的默奇森陨石轰然坠落在澳大利亚。

2 meteorites   

n.陨星( meteorite的名词复数 )

参考例句：

• Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
• One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》

3 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

4 asteroid   

n.小行星；海盘车(动物)

参考例句：

• 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。

5 asteroids   

n.小行星( asteroid的名词复数 )；海盘车，海星

参考例句：

• 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。