The Sea of Tranquility is one of many named locations on the moon.

This month, I'll be taking you on a guided tour of the moon. Hello and welcome. I'm Jane Houston Jones with NASA's Jet Propulsion Laboratory in Pasadena, California. The moon has some great features that you can see with the unaided eye. First, look for bright rays, or long white lines. These are streaming from impact craters on the moon's surface. These craters and their dramatic rays were created less than one billion years ago when asteroids or comets hit the moon. Another really cool site you can see without a telescope is the Sea of Tranquility. This is where the Apollo 11 astronauts took humankind's first steps on the moon in 1969. You won't be able to see their footsteps or the flag they planted or the spacecraft, even with a telescope. Now here are some facts about the moon. It takes about 29 days to go around the Earth once, and it also takes the moon about 29 days to spin once on its axis.  This means we always see the same side of the moon.
As the moon orbits Earth, the portion we see illuminated changes. We call these changes phases. The first phase, called the new moon, is  just a sliver and difficult to see at first, but each night it gets bigger and brighter. The next phase is called the first quarter moon because it has traveled one quarter of its 29-day orbit.  It's the easiest phase to observe. It rises at noon and sets at midnight. A full moon is the next phase. The moon is behind Earth in space with respect to the sun, The last quarter moon follows the full moon. Each night it rises later, and we see less of it.  We'll have more to say about the moon next month, plus meteors and Mars. To learn more about all of NASA's missions, visit www.nasa.gov .
You can email me questions, get a moon map or sky charts at education.jpl.nasa.gov . Just click on the What's Up button. That's all for this month. I'm Jane Houston Jones.  

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