What can you conclude about the interior of the planet based on seismographs?

3. Several years ago, NASA conducted the Lunar CRater Observation and Sensing Satellite (LCROSS) mission to look for evidence of water deep in craters near the south pole of the Moon (www.nasa.gov/mission_pages/LCROSS/main/index.html). Preliminary analysis of the LCROSS data has already demonstrated that there are indeed signifcant quantities of water on the Moon-a useful thing to know if we ever decide to build a permanent base on the Moon. The LCROSS spacecraft was launched from Earth aboard at Atlas V rocket on 18 June 2009. It was then sent on its way to the Moon by a Centaur transfer stage rocket. On 9 October 2009, while being observed by the LCROSS spacecraft, the Centaur rocket crashed into a crater at the south pole of the Moon creating a huge plume of Lunar dust. Instruments on the LCROSS spacecraft measured the spectroscopic properties of this dust and radioed this data back to Earth for analysis. Then, 4 minutes after the Centaur rocket impacted the Moon, the LCROSS…

21) Why doesn't Venus have as many craters as Earth's moon?

5) Why doesn't Earth have as many craters as the moon?