The moon is one of the celestial bodies most studied by scientists. Today, we know that it is an opaque satellite without the ability to emit its own light. But then why does the moon shine if it doesn’t have its own light? . Of course it is a most curious phenomenon and many people wonder why it shines and sometimes with such intensity.
Why is the moon shining
The surface of the moon reflects the sunlight it receives and that is why we perceive it brightly, but although it sometimes seems to shine a lot (especially during a full moon), it really only reflects between 3% and 12% of the light of the Sun. This percentage is calculated by scientists using a measurement called albedo, which is defined as the percentage of radiation reflected by a surface with respect to the total radiation that falls on it. For example, snow has an albedo of 0.95 or 95% of the total it receives (which is why we see it white), while the moon has an albedo of 0.07 or 7% of the total it receives. Although the percentage of radiation reflected by the moon is not too high, we see the moon very bright due to its proximity to the Earth .
In addition, the tone with which we usually perceive the moon is slightly silver, which is also due to the fact that it receives part of the light that the Earth reflects from the sun, because our planet is also an opaque celestial body with the ability to reflect light. solar (its albedo is 0.38).
Why does the moon shine explanation for children
To explain this curious phenomenon to children we can say that the moon does not shine itself, it does not have its own light, but that the moon shines because it gives it sunlight . At night, which is when we see the moon, the sun is behind it and, for this reason, the intense light that the sun itself has reaches it. Thus, the moon shines thanks to the sunlight that reaches it and we see it whiter and brighter when it is bigger, on a full moon.
The surface of the moon has a dark gray hue. It is made up of minerals that result from the disintegration of basaltic rocks, anorthosites (an igneous rock) and lunar dust (which comes from bombardment of Hydrogen by the solar wind and the existence of Iron in metallic form).
The composition of the moon is important, since the lunar composition helps us to observe the moon with a greater brightness than it reflects. Light from the sun, X-rays and ultraviolet radiation produce alterations in the state of their electrons in materials on the lunar surface and cause their surface to acquire a greater positive charge. This fact causes the smallest particles of lunar dust to be released into space (in an orbit that ranges from a few meters to several kilometers). It is the movement of particles around the moon that ultimately causes the effect of reflecting a greater intensity of light.
The moon’s orbit and phase influence the brightness of the moon
The brightness that we observe on the moon depends mostly on the moment of its orbit around our planet. We, from the planet, will only be able to observe the half of the moon illuminated by the sun. The orbit that the moon describes around the Earth is completed in about 29 and a half days and at different points of its path it is illuminated by the sun from different angles .
It is the combination of the lunar orbit around the Earth with the Earth’s orbit around the sun, which creates the different phases of the moon that we know: new moon, crescent moon, crescent quarter, crescent gibbous moon, full moon, moon waning gibbous, last quarter, waning moon and black moon. At any point in this lunar orbit , only half will be facing the sun and therefore illuminated, while the other half will be in the shadows and not visible to people.
The brightest point on its trajectory is when it is about 180 degrees from our perspective. Moment in which half of its surface is in front of the sun and is completely illuminated, being fully visible from the Earth. Thus, the phenomenon of the full moon is when the moon shines the brightest .
On the contrary, during the new moon phase, the moon is not visible from the Earth, because at this point in its trajectory, the moon is located between the sun and the Earth and the side of the sunlight that reflects the moon, its back is to the Earth
This is another common doubt, especially among those who still do not know that the moon does not have its own light, in addition to being used in riddles.
After what we have already explained, the answer to the question of which sun or moon shines brighter seems quite clear. Indeed, the sun shines more than the moon , since it has its own light and the natural satellite of the Earth does not. In addition, an easy way to check it yourself is to look at both directly, you will notice that you can look at the moon much longer without bothering your eyes, while the sun can barely look directly for a few seconds, because it dazzles you because it shines a lot. plus.