原文已被隐藏，你可用 快捷键 - 或点击 显示原文 按钮来查看原文
第1段
1 .This is Scientific American 60-Second Science. I'm Christopher Intagliata.Got a minute?
该句暂无译文！
2 .Every day, 100 tons of space dust rain down on the Earth's atmosphere.
该句暂无译文！
3 .By night, we know this material as shooting stars.
该句暂无译文！
4 .And our neighbor the moon is likewise exposed to that debris—but without an atmosphere to stop it.
该句暂无译文！
5 .So all those particles strike the moon's surface, at 12 miles per second, like tiny bullets.
该句暂无译文！
6 .And each impact kicks up a thousand times its weight, in moondust.
该句暂无译文！
7 .Mihály Horányi, a physicist at the University of Colorado, makes this analogy:
该句暂无译文！
8 ."Imagine you are making pasta and there's flour on the table, and you get impatient and upset and you smack the table.
该句暂无译文！
9 .There's going to be a whole cloud of tiny particles, you know, flying off the table."
该句暂无译文！
10 .Horányi and his colleagues sampled that cloud of particles with NASA's Lunar Atmosphere and Dust Environment Explorer, or LADEE, as it orbited the moon, slurping up dust.
该句暂无译文！
11 .Judging by the shape and density of the dust cloud, the scientists say the particles striking the moon and kicking up the cloud must be mostly high-speed comet grains, rather than slower bits of asteroid.
该句暂无译文！
12 .And, as you might expect, the moon's halo of dust increases during heavy bombardment, the same time that we have meteor showers here on Earth.
该句暂无译文！
13 .The findings are in the journal Nature.
该句暂无译文！
14 .There is one mystery these measurements do not solve: the source of the strange "horizon glow" the Apollo astronauts observed on the moon.
该句暂无译文！
15 .Because Horányi says that, based on these samples, there just isn't enough dust to create the visual effect the astronauts saw.
该句暂无译文！
16 .Not that this is 'case closed.'
该句暂无译文！
17 ."There is not a single paper or a single measurement that I can claim to be the last word on anything, so, no, as always, there are more questions and open issues.
该句暂无译文！
18 .But one way to figure out is to try it again.
该句暂无译文！
19 .Send people. Orbit the moon again and see if we have better instruments and take better images, see if we could resolve this."
该句暂无译文！
20 .But if NASA's current plans are any indication, it might be a while before any American astronauts see that glow firsthand.
该句暂无译文！
21 .
该句暂无译文！
22 .Thanks for the minute, for Scientific American 60-Second Science. I'm Christopher Intagliata.
该句暂无译文！