By Ranger Steve

Two nights of Earth Shine has brightened my spirit and eyes under a clear dark sky. The Earth follows a path around the sun that takes 365 days and creates our planet’s year. Earth is a satellite of the big hot yellow ball we call sun. We are not the only planet held by the sun. Without its constant light and heat, nature niches filled with life would not exist. Take joy in the sunlight daily.

Our home planet, Earth, has it own satellite we call the moon. The moon does not have an atmosphere and that prevents establishment of conditions for life. It has mountains and valleys. Craters that mark the surface can be easily seen with binoculars, a small telescope, or spotting scope used by bird watchers. The best views of ridges and valleys are seen along the edges of the moon where the curve of the surface allows us to see greater detail.

Think of the moon like a baseball. When one looks at the surface stitching of a baseball, the surface closest to you will not appear as rough or elevated as the stitching along the edges where we can see the relief of valleys and ridges among the threads more easily.

The moon appears to rise about 56 minutes later each night. View it from your yard on a full moon night when the Earth is between the sun and moon. Rarely the three objects are aligned so perfectly straight that the Earth’s shadow blocks sunlight from hitting the moon. When they do, we have a moon eclipse. When the moon is between the sun and Earth in perfect alignment, its shadow blocks sunlight from hitting Earth creating a solar eclipse. Such perfect alignments are rare and make the news.

About every 28 days, the moon moves around the Earth in a similar manner to how the Earth moves around the sun. As a result, we see different amounts of the moon’s surface lighted by the sun. On a full moon night, it appears that the entire moon is lighted by the sun and we see a bright round ball. The Earth is between the sun and moon on those nights. Keep in mind that half of the moon is dark with no sunlight when we see a full moon. That half is the surface facing away from us so we do see any of the dark side.

When the moon and sun are both on the same side of the Earth at sunset or sunrise, the dark side is facing us and is not being hit by sun rays. We call it a new moon. We can still see the dark circle of the moon and this is where Earth Shine becomes important. If no light at all was coming from the moon’s surface to Earth, we would not see it.

This past week on clear nights shortly after sunset, we observed a small bright crescent moon. The entire half of the moon was reflecting bright light from the sun but almost all of the lighted portion of the moon was facing away from Earth. With the moon between Earth and sun, the dark side was facing Earth except for a thin strip of the lighted portion. The next night the moon’s positon had changed and it was setting 56 minutes later so it was not aligned as straightly with sun. The moon showed a wider bright crescent.

Perhaps only 10 percent of the moon seen was a brightly lighted crescent. However, the other 90 percent was also visible. With no sunlight hitting it directly, one would expect it should be absolutely black and invisible. There is no moon atmosphere to reflect light onto the dark surface of the moon.

Sunlight hitting the Earth bounces off our planet’s surface, hits the moon, and bounces back to Earth. There is enough reflected sunlight bouncing off Earth to hit the dark side of the moon and even bounce back to Earth so we can actually see the surface that receives no direct sun rays. The dimly visible lighted 90 percent is a result of Earth Shine. The Earth does not produce its own light but it does reflect enough sunlight to create Earth Shine on the moon.

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.