Answers to Go with Susan Smith

Q. Do you have books for children that explain phases of the moon? We were outside on Sunday, March 18 just after sunset and saw a tiny sliver of moon. Can you tell me when that will happen again?

A. The moon will be new on Monday, April 16, 2018. During a new moon, the moon cannot be seen because no sunlight reflects off the side facing Earth. The illumination level of the new moon’s visible surface from Earth is zero percent.

Let’s turn to “The Handy Space Answer Book” written by Phillis Engelbert and Diane L. Dupuis for details: “The lunar cycle begins with a new moon, one that is not visible. A new moon occurs when the moon is positioned between the Earth and the sun. Since sunlight strikes the side of the moon facing away from us, we cannot see the moon at all.”

I looked online to see details for the current phases of the moon.

On Tuesday, April 17, the moon will be in a waxing crescent phase. This is the first phase after the new moon. During this phase, the moon can be seen in the western sky after the sun dips below the horizon at sunset. The moon is close to the sun in the sky and mostly dark except for the right edge of the moon.

There is sort of a mirror image process that happens immediately before the new moon. On Saturday, April 14, the moon will be in a waning crescent phase with 3 percent illumination. In this phase, the moon’s illumination is growing smaller each day until the new moon.

During this phase, the moon is getting closer to the Sun as viewed from Earth and the night side of the moon is facing the Earth with only a small edge of the moon being illuminated. This phase is best viewed an hour or two before sunrise and can be quite beautiful if you’re willing to get up early.

It can also be a great time to see the features of the moon’s surface. Along the edge where the illuminated portion meets the dark side, the craters and mountains cast long shadows making them easier to observe with a telescope or binoculars.

On Sunday, April 15, the moon is technically still waning, but the chart shows the level of illumination as zero percent. Another source shows the moon as new on both April 15 and 16.

All of this is explained simply with diagrams in these books in our juvenile non-fiction collection: “Why Does the Moon Change Shape?” by Melissa Stewart; “Tell Me Why the Moon Changes Shape” by Kathryn Beaton; “The Moon and You” by E.C. Krupp; and “Exploring the Moon” by Rebecca Olien.

San Marcos Daily Record

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