Does The Moon Produce Its Own Light?

On most nights, especially when the sky is clear, the ever-present moon is visible above, providing a bright glow. 

This glow can be so luminous when the moon is full that it can allow you to see effectively, even at full dark. 

Yet, have you ever wondered just why the moon is visible through all that space and why it glows so brightly? Does the moon produce light, or is there another explanation for this phenomenon? 

Read on, and you will be illuminated with answers to this question and others!

How does the moon shine?

Space is an all-encompassing void of darkness, save for the stars and moon. So how is it that they can be seen, even from millions of light-years away?

Does the moon generate its own light, like the Sun?

In short: No, the moon does not produce light. Although the answer to its luminosity is related to the Sun! 

When you see the moon glowing at night, what you are actually seeing is the light of the Sun.

Just because the Sun is no longer visible in the sky does not mean that it isn’t still out there, shining brightly out of view. 

Does the Moon Reflect the Light of the Sun?

Rays of sunlight strike the moon, which in itself is just a dull orb (like the Earth), and what you are witnessing is the reflection of those rays off the surface and crater rims. 

Since they are bouncing off the moon, it gives the moon the illusion of a glow. The moon’s brightness will depend on how much of the moon is visible at a given time. 

When you see the moon in its full-moon glory, it seems so much brighter because you see more light reflected at that time.

Why Isn’t the Moon Full All the Time?

So, if the sunlight is reflecting off the moon, why can’t you see it all the time?

Well, the moon itself doesn’t change. It’s an orb floating in space, just like Earth and the other planets. 

What changes is what we can actually see and where everything is placed in the celestial scheme of things. Various factors explain why we don’t see the full reflection of the Sun’s light off the moon at all times. 

The first reason is the easiest to explain. Weather conditions on Earth can obscure our view of the moon in general.

On some nights, the moon is hidden behind thick layers of clouds, so while it may be up there, you simply can’t see it.

Other times, you may see the cloud’s “silver lining,” and that is the light reflecting off the moon showing behind them.

The other major reason is that the Earth revolves around the Sun, and the moon orbits the Earth. Since both are in motion, they are placed differently in relation to the Sun and each other at different times. 

It takes a month for the moon to orbit the Sun, and we only ever see half the moon at any time (the side currently facing us).

So during its journey, depending on where it currently is in relation to our planet, we can only see a portion of the Sun’s light reflected. That’s why we have the phases of the moon. 

At times, we can’t see anything because we are not at an angle where we can view the Sun’s reflected light. However, we can see a portion of that light other times, making the moon appear crescent-shaped.

When we are directly positioned to see the entirety of the moon’s visible half, that is our full moon (source). 

Is Looking at the Moon Bad for Your Eyes?

The moon isn’t nearly as bright as the Sun, so looking at it with your naked eyes will not harm them.

However, if your eyes begin to water or sting, it may be a good idea to give them a rest.

Unlike the Sun, you also should face little risk by viewing the moon through a telescope since these are reflections of light rather than a direct source. Although, the increased intensity of the magnifying lenses can enhance issues related to visual discomfort. 

If you find yourself suffering from these effects, you can actually purchase moon filters. These make viewing it for longer periods more comfortable.

The same cannot be said for a solar eclipse. You should not view this phenomenon with a telescope or your naked eyes as this can seriously damage your eyes.

How do eclipses occur?

Two to four times a year, the moon will reach a point in its rotation where it slides right between the Earth and the Sun. 

When that happens, a solar eclipse occurs.

As the moon passes between the Sun and Earth, the light from the Sun reflects off it, and the moon’s shadow falls over the Earth, creating darkness.

Once every hundred years or so, this placement is so perfect that it completely blocks out the Sun, creating a total eclipse. 

In that instance, it actually becomes as dark as night during the daytime, at least until the moon continues on its way and light gradually returns. 

This works in reverse, too! Sometimes at night, the moon and Sun reach a perfect alignment, and the Earth slides into place between them, creating a lunar eclipse. 

This happens during the full moon as we are perfectly aligned to see all the light reflected. However, when the Earth passes between them, it blocks the light from reaching the Sun, dimming the moonlight.

When that alignment is just right, it creates a total lunar eclipse. However, the moon doesn’t entirely disappear because the Sun’s rays strike the Earth and are refracted into its atmosphere.

Remember, sunlight is why the Earth glows, too! Only because of this refraction, rays of light from Earth strike the moon and turn it red!  

Why? 

Since that light enters our atmosphere before it hits the moon, it passes through dust, water droplets, and various gases, which give the light a reddish hue as it strikes the moon.

Sometimes, during a lunar eclipse, the moon is called a blood moon (source). 

Do stars produce their own light?

Yes! Stars produce their own light, just like our Sun.

Stars generate an intense amount of heat on their own, which produces light. This is very similar to light generated when we make a fire here on Earth.

Nuclear reactions occur within the star, which generates intense heat, and the light provided is a byproduct of this. For example, the Sun turns hydrogen to helium within itself in a process called nuclear fusion (source).

Do Planets reflect light? 

Just as the Earth and moon glow from the Sun’s light, so do other planets. Depending on their positioning based on the Sun and Earth, you can actually see them.

They often resemble stars, but the closer planets are brighter and typically have a consistent light, i.e., they don’t twinkle like stars. 

You can see most of them with the naked eye except Uranus and Neptune, which can be viewed with a small telescope as they are so far away and enjoy less access to the Sun’s rays (source).

Conclusion

Nuclear fusion is required to produce light. Stars, including the Sun, create nuclear fusion and produce their own light.

The light that appears to be shining from the moon and planets is a reflection of the light produced by the Sun.