The phenomenon of the Moon appearing red in color is known as a "blood moon" or "red moon." There are a few different situations that can cause the Moon to take on a reddish hue:
Lunar Eclipse: During a total lunar eclipse, the Earth comes between the Sun and the Moon, casting a shadow on the Moon's surface. However, instead of blocking all sunlight, some of it gets refracted (bent) by the Earth's atmosphere and filters through the atmosphere to reach the Moon. The Earth's atmosphere scatters shorter wavelengths of light (such as blue and green), while longer wavelengths (such as red and orange) pass through more easily. As a result, the light that reaches the Moon during a lunar eclipse is primarily red, causing it to appear red or orange.
Atmospheric Conditions: At certain times, the Moon can also appear red or orange when it's low on the horizon, just after rising or before setting. This effect is similar to the way the Sun appears reddish during sunrise or sunset. When the Moon is near the horizon, its light has to pass through a thicker layer of the Earth's atmosphere, which scatters shorter wavelengths of light and allows the longer wavelengths (red, orange, and yellow) to dominate. This atmospheric scattering can give the Moon a reddish tinge.
It's important to note that the exact appearance and intensity of a red Moon can vary depending on the specific atmospheric conditions, such as the amount of dust, smoke, or pollution in the air.