A lunar eclipse occurs when the Moon moves into the Earth’s shadow. This can occur only when the Sun, Earth, and Moon are exactly or very closely aligned with Earth between the other two, which can happen only on the night of a full moon when the moon is near either lunar node.
Why Blood Moon then? It’s not a scientific term but it is widely used as the Moon takes on a reddish or really red colour. Blood Moon refers to a total lunar eclipse which happens around twice a year.
A total lunar eclipse, like the one on the video that took place early morning today, happens when the Moon travels through the Earth’s umbra (the dark centre part of the shadow) and blocks all direct sunlight from illuminating the Moon’s surface. Some of the Sun’s rays pass through the Earth’s atmosphere (the part of the light spectrum closer to the red) in a phenomenon called Rayleigh Scattering (also responsible for the sky being blue) causing the Moon to take on red colour