Curated by RSF Research Staff
Super Blue Blood Moon Eclipse
Get ready for a rare cosmic event this Wednesday 31st January 2018 when the full moon will not be like any old full moon.
We see a full moon when the path of the Moon about the Earth lines up with the path of the Earth about the Sun, such that the illuminated face of the Moon is visible from Earth. This full moon alignment happens approximately every 29 days and is technically known as syzygy of the Sun-Earth-Moon-system. When the Moon passes directly behind the Earth into its shadow, we see an eclipse. However, when this alignment is exact, such that the Suns light is completely blocked by the Earth’s shadow, we see a total eclipse. During a total eclipse, the only light that we see reflected from the Moon is light that has passed through the Earths atmosphere. In an effect known as Rayleigh scattering – where light is scattering with no effect on its wavelength – the Suns rays interact with the Earths atmosphere scattering the light in different directions. The more energetic blue rays, with a shorter wavelength, are the most affected, whereas lower energy rays, with longer wavelengths, pass straight through the Earths atmosphere where they are refracted around the Earth to the Moon. It is these refracted rays that give the Moon a reddish-orange colour during an eclipse – which is sometimes referred to as a blood moon.
Tomorrows eclipse is a total lunar eclipse – a blood moon – and will be the first total eclipse in 2.3 years. It is also the second full moon in one month, which happens every 2.7 years and is known as a blue moon. The path of the Moon about the Earth follows an elliptical orbit and is currently at its closest point to Earth – known as perigee – which can make the Moon appear slightly larger and brighter than normal and is thus referred to as a supermoon.
This rare event will be visible from California just before sunrise, where totality will begin at 4:51am, peaking at 5:28am and ending at 6:07am.