Kentucky.
Why Is the Moon Sometimes Visible During the Day?
T his Imponderable would be so easy to answer if the sun, moon, and Earth would get together and agree on a uniform schedule. But they refuse to do so, keeping astronomers and astrologers in business, and making it hard for us to provide a simple answer.
Here’s the simple answer, anyway. The moon does not shine by its own light. When we see the moon, it’s only because we are seeing the reflection of sunlight bouncing off its surface. You can see the moon in the daytime when the sun and the moon are located in the same direction in the sky. As the moon proceeds on its (approximately) twenty-nine-day orbit around the Earth, at times it’s on the opposite side of the Earth from the sun.
Although we may remember this only when we’ve been indulging in too many recreational substances, the Earth is also spinning on its axis once every twenty-four hours, a much shorter time than it takes the moon to revolve around us or for the Earth and moon together to orbit around the sun (a year). Though we perceive the moon as rising and setting as it “moves” across the sky, it’s really the Earth rotating on its axis (“underneath” the moon) that causes this effect. In one day, the moon doesn’t move much relative to the sun or to the Earth, even though during these twenty-four hours, we see a complete cycle of day and night because of our planet’s spinning.
Viewing of the moon is also contingent on the state of the Earth’s atmosphere. The stars are “out” during the day, but we can’t see them because the scattered light from the sun is bright enough to drown out the relatively dim light from the stars. But the moon is the second brightest object in the sky, next to the sun, so even though it appears pale, we can usually see it during the day if it is close in direction to the sun. But on days with excessive glare or cloudiness, the moon may not be visible, especially just before and after a new moon.
Even though the moon and sun often appear to be close together, the sun is always about 400 times farther away from Earth than the moon. We can see the moon during the daytime when the sun and moon are relatively close in direction, but not too close! When they are aligned too closely, we can’t see the moon because the sun is directly behind it and can’t light up the side of the moon facing us. When they are in opposite directions, in the daytime, the sun is overhead but the moon is on the opposite side of the Earth.
When the moon is overhead, you do see it, but it is night because the sun is on the other side of the Earth. It’s when the moon and sun are at right angles, or close to it, that you can best see the moon during the day—the sun, moon, and Earth form a big triangle, and the sun is “in front” of the moon to light up the side of the moon that is visible to us, and it’s daytime because the sun is up in the sky above us.
Still confused? Maybe this analogy from Tim Kallman, an astrophysicist at the Laboratory for High Energy Astrophysics at NASA, will help:
It might be useful to think of the sun as a large light bulb, and the moon as a large mirror. There are situations where we can’t see the light bulb, but we can see the light from the bulb reflected in the mirror. This is the situation when the moon is out at night. We can’t see the sun directly because the Earth is blocking our view of it, but we can see its light reflected from the moon. However, there are also situations where we see both the light bulb and the mirror, and this is what is happening when we see the moon during the day.
Submitted by Glen Kassas of Concord, New Hampshire. Thanks also to Caroline and Cathy Yeh, of parts unknown; Margaret Paul Vitale of Palermo, Italy; and Terry Keys, Jr. of Friendswood, Texas.
How Do They Get the Paper Tag into Hershey Kisses? And Why Are They Called Kisses?
T he origins of Hershey
Why Is the Moon Sometimes Visible During the Day?
T his Imponderable would be so easy to answer if the sun, moon, and Earth would get together and agree on a uniform schedule. But they refuse to do so, keeping astronomers and astrologers in business, and making it hard for us to provide a simple answer.
Here’s the simple answer, anyway. The moon does not shine by its own light. When we see the moon, it’s only because we are seeing the reflection of sunlight bouncing off its surface. You can see the moon in the daytime when the sun and the moon are located in the same direction in the sky. As the moon proceeds on its (approximately) twenty-nine-day orbit around the Earth, at times it’s on the opposite side of the Earth from the sun.
Although we may remember this only when we’ve been indulging in too many recreational substances, the Earth is also spinning on its axis once every twenty-four hours, a much shorter time than it takes the moon to revolve around us or for the Earth and moon together to orbit around the sun (a year). Though we perceive the moon as rising and setting as it “moves” across the sky, it’s really the Earth rotating on its axis (“underneath” the moon) that causes this effect. In one day, the moon doesn’t move much relative to the sun or to the Earth, even though during these twenty-four hours, we see a complete cycle of day and night because of our planet’s spinning.
Viewing of the moon is also contingent on the state of the Earth’s atmosphere. The stars are “out” during the day, but we can’t see them because the scattered light from the sun is bright enough to drown out the relatively dim light from the stars. But the moon is the second brightest object in the sky, next to the sun, so even though it appears pale, we can usually see it during the day if it is close in direction to the sun. But on days with excessive glare or cloudiness, the moon may not be visible, especially just before and after a new moon.
Even though the moon and sun often appear to be close together, the sun is always about 400 times farther away from Earth than the moon. We can see the moon during the daytime when the sun and moon are relatively close in direction, but not too close! When they are aligned too closely, we can’t see the moon because the sun is directly behind it and can’t light up the side of the moon facing us. When they are in opposite directions, in the daytime, the sun is overhead but the moon is on the opposite side of the Earth.
When the moon is overhead, you do see it, but it is night because the sun is on the other side of the Earth. It’s when the moon and sun are at right angles, or close to it, that you can best see the moon during the day—the sun, moon, and Earth form a big triangle, and the sun is “in front” of the moon to light up the side of the moon that is visible to us, and it’s daytime because the sun is up in the sky above us.
Still confused? Maybe this analogy from Tim Kallman, an astrophysicist at the Laboratory for High Energy Astrophysics at NASA, will help:
It might be useful to think of the sun as a large light bulb, and the moon as a large mirror. There are situations where we can’t see the light bulb, but we can see the light from the bulb reflected in the mirror. This is the situation when the moon is out at night. We can’t see the sun directly because the Earth is blocking our view of it, but we can see its light reflected from the moon. However, there are also situations where we see both the light bulb and the mirror, and this is what is happening when we see the moon during the day.
Submitted by Glen Kassas of Concord, New Hampshire. Thanks also to Caroline and Cathy Yeh, of parts unknown; Margaret Paul Vitale of Palermo, Italy; and Terry Keys, Jr. of Friendswood, Texas.
How Do They Get the Paper Tag into Hershey Kisses? And Why Are They Called Kisses?
T he origins of Hershey
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