What is a Blood Moon in Astronomy?

A blood moon, also known as an lunar eclipse, occurs when the Earth passes between the Sun and the Moon, casting a shadow on the lunar surface.

Understanding Lunar Eclipses

Lunar eclipses occur when the Moon moves into the umbra of the Earth’s shadow. The Earth’s umbra is much smaller than its penumbra, so only a narrow region of the Moon can blood-mooncasino.com be completely within the umbra at any given time. This results in one to three small black patches on the surface of the lunar disk during an eclipse.

There are several types of lunar eclipses:

• Penumbral Lunar Eclipse : The Earth’s shadow falls partially over the face of the Moon, causing a subtle darkening of its brightness.
• Partial Lunar Eclipse : A portion of the Moon passes through the umbra, resulting in a partial darkness and sometimes some brighter or darker regions around the limb.
• Total Lunar Eclipse : A total lunar eclipse occurs when the entire face of the Moon enters into the Earth’s shadow. The Earth’s atmosphere scatters sunlight towards the Moon during this time, giving it a reddish hue.

The Cause of the Red Color

During an occultation or lunar eclipse, light has to pass through much greater thicknesses of the terrestrial atmosphere than in normal full moon conditions. This means that when we see a total lunar eclipsed (TLE) or Penumbral Lunar Eclipse, there is more scattering due to atmospheric molecules such as Rayleigh-scattered blue and violet rays being absorbed at Earth’s surface.

The remaining red light gets scattered back into the observer’s line of sight because these wavelengths pass through much less atmosphere than the blues, making this event appear a deep blood-red.