#Astronomical phenomena march 1921 full#

This means that lunar tetrads are rare occurrences, leading some to attach special, even religious, significance to these events. Usually, only about one in three lunar eclipses are total, and about four to five total eclipses can be seen from any single location on Earth in a decade.

#Astronomical phenomena march 1921 full#

The eclipses in a tetrad occur about six months apart with five uneclipsed Full Moons between them.

The term Blood Moon is also sometimes used to refer to four total lunar eclipses that happen in the span of two years, a phenomenon astronomers call a lunar tetrad. Red wavelengths are least affected by this effect, so the light reaching the Moon's surface has a reddish hue, causing the fully eclipsed Moon to take on a red color.ĭepending on the composition of the atmosphere, different parts of the light spectrum are filtered out, so the Moon may also look yellow, orange, or brown during a total lunar eclipse. This is the same mechanism that causes colorful sunrises and sunsets. However, some sunlight still reaches the lunar surface indirectly, via the Earth's atmosphere, bathing the Moon in a reddish, yellow, or orange glow.Īs the Sun's rays pass through the atmosphere, some colors in the light spectrum-those towards the violet spectrum-are filtered out by a phenomenon called Rayleigh scattering. Why Are Blood Moons Red?īlood Moon is not a scientific term, though in recent times it is being widely used to refer to a total lunar eclipse because a fully eclipsed Moon often takes on a reddish color-like in the image below, which was taken during the total lunar eclipse in September 2015.Ī total lunar eclipse happens when the Moon travels through the Earth's umbra and blocks all direct sunlight from illuminating the Moon's surface.

Business Date to Date (exclude holidays)Įarth's atmosphere filters out blue light.