Rare “super blue blood moon” lights up the night sky as stargazers witness phenomenon seen every 150 years.
On the night of January 31st 2018, the night sky lit up with the arrival of what had been dubbed a “super blue blood moon.”
What is a supermoon, a blue-moon and a blood-moon?
A supermoon usually takes place every one or two years when then full moon cycle coincides with the moon’s closest point to Earth during its monthly orbit.
The moon has an elliptical orbit, one side (called the perigee) is about 48,280 km (30,000 miles) closer to the Earth than the other side (the apogee).
When the sun, the moon and the Earth line up as the moon orbits the Earth, that is known as syzygy!
When the perigee side of the moon is facing us and the moon is on the opposite side of Earth from the sun, this is called a perigee-syzygy.
This perigee-syzygy is what causes the moon to appear much bigger and brighter in the sky than usual, often referred to as a supermoon.
Because this is the second supermoon of the month, it takes on the name ‘blue moon’ – an event that happens every couple of years.
In addition to being not only a supermoon, but also a blue moon, the moon of January 31st will also feature a lunar eclipse, turning the moon red in colour.
Why is it called a #SuperBlueBloodMoon?
🌕Supermoon – When the Moon is at or near its closest point to Earth
🔵Blue Moon – The second full moon in a month
🔴Blood Moon – The red tint Earth’s shadow casts on the Moon during a lunar eclipse
— NASA (@NASA) January 31, 2018
A spokesperson for NASA said: “The moon’s orbit around our planet is tilted so it usually falls above or below the shadow of the Earth
“About twice each year, a full moon lines up perfectly with the Earth and sun such that Earth’s shadow totally blocks the sun’s light, which would normally reflect off the moon.”
This is the first time the UK had experienced a blue moon lunar eclipse in 150 years.