When we have a morning or afternoon with clear, blue skies, you just might the moon in the sky.
It turns out, you have an opportunity to see the moon in the sky most of the month, if the weather is good. Though, it's easier to spot if it's close to full and bright.
We see the moon because it's brighter than the natural brightness of a blue sky.
If the skies were hazy, milky, or humid, the skies would end up being brighter than the moon. So, you wouldn't see it.
As long as these clear, blue skies continue, you have an opportunity to see the moon. Look in the west sky to see the moon during the day before it sets.
Like the sun, the moon sets in the west sky.
We can also see the moon right now because it is not full or new.
You can't see a full moon during the day because full moons rise around sunset and set around sunrise: they're only out at night.
After a full moon, the moon keeps setting later each day. On Tuesday, December 1, the moon set about an hour after sunrise at 7:53 a.m. On Wednesday, December 2, the moon set at 8:48 a.m.
And, the pattern continued with the moon setting about an hour later each day.
With the moon setting later and later, we have a chance to see the moon during the day.
Soon, the moon will start setting a half hour later each day. This leads to the moon setting around 5:40 p.m. when we get the next new moon on Monday, December 14.
After the new moon, the moon will keep setting a half an hour later each night for a while. Then, as it approaches the full moon, it'll start setting an hour later each night. By the time we get the full moon on December 29, the set time will be back to around sunrise again.
These different set times explain why you don't see a moon in the sky when you're outside some nights. You're missing it!
If you don't see it, you're outside before the moon rises or after the moon sets, provided it's not the night of the new moon.
Take Thursday, December 3, for example: the moon doesn't rise until 8:22 p.m. Because sunset is at 4:43 p.m., we won't see the moon for the first few hours of the night sky.
The moon rise and set times change with the seasons.
The moon is only up all night when it's a full moon.
When the moon is not full, we get to see it during the day because of the way the moon moves around the Earth.
As the moon moves around the Earth, it gets into certain positions so that it's visible in our skies.
An exception is a new moon.
At that point in the moon's orbit, the moon moves in front the sun.
This causes the sun to shine on the back of the moon (also known as the far side of the moon). Because the side of the moon we see lacks sunlight, we don't see any bright moonlight day or night when it's a new moon.
As the moon continues to move around the Earth, sunlight starts hitting the moon at a different angle, giving the moon a crescent-shape illumination. The farther from the sun or closer to the sun the moon gets, the bigger or smaller the crescent moon appears.
Eventually, the moon moves to a position where it's across from sun. In other words, the Earth is directly between the moon and sun.
When this happens, the side of the moon that we see is fully illuminated by the sun. So, we see a bright full moon.
When we watch the moon going through its phases, we are really observing the moon going through a day and night cycle as it orbits the Earth, says Moravian College Astronomy Professor Gary Becker. It takes the moon about 29.5 days to move around the Earth, which is why the dates of the full and new moon change each month.
By the way, a new moon can entirely block our view of the sun. It just doesn't happen often.
It last happened in August 2017 when some parts of the United States, like Tennessee, saw a total solar eclipse.
Check out a 360-degree video of that full eclipse shot up on a ridge in Tennessee.
The moon completely blocked the sun for a few minutes. It got so dark during that time that some planets were visible. Lights even came on in the town in the valley below!
It turns out that planets and stars are always up in our sky during the day, but normally the sun is too bright for us to see them.
Your next chance to see stars in the middle of the afternoon is April 8, 2024, our next total solar eclipse.
This time, you won't have to travel as far as Tennessee to see it. It'll be visible in parts of of northwest Pennsylvania and Ohio.
Thanks to NASA Ambassador Marty McGuire and West Chester University Mather Planetarium director Dr. Karen Swartz for their help with this story. A big thanks goes to Professor Gary Becker who edited the space science in this story.
If you got a picture of the moon while it was in the blue skies this week, send it to email@example.com with the location and when you took it.