Transcripts of lro_lend_video_ipod_lg

[silence] [silence] [music] Narrator: If you were to go looking for water on the Moon, how would you find a good place to start digging? NASA's Lunar Reconnaissance Orbiter has a pretty unique answer: Count the neutrons coming from the Moon! LRO's LEND instrument, or Lunar Explorer Neutron Detector, is specifically designed to do just this. But how does counting neutrons help you find water? The answer lies in hydrogen--the smallest atom--and how those neutrons interact with it. So where do those neutrons come from, and what do they do? The Moon is constantly bombarded by cosmic rays. Sometimes, these rays hit atoms in the Moon's soil and knock off a neutron or two. These neutrons then go bouncing across other atoms before heading off into space. In soil that doesn't contain much hydrogen, the neutrons are much smaller than the surrounding atoms they crash into, so they don't slow down too much. However, in soil containing larger amounts of hydrogen, some of the neutrons hit the similarly-sized hydrogen atoms, which absorb a good deal of the neutrons' energy and slow them down. By measuring the varying amounts of slow and fast neutrons, LEND can effectively measure the likely amount of hydrogen in different areas of the Moon. And that being said, scientists think that where there's hydrogen, there's a good chance there's water. So LEND will keep counting neutrons, and LRO will keep looking for water on the Moon. [music, beeping] [music, beeping] [music] [silence]