An unusual set of celestial circumstances came together over Sunday night and the wee hours of Monday for sky watchers in Europe, Africa and the Americas, where the moon was fully obscured before lighting up again with a faint red glow.
It was also the year's first supermoon, when a full moon appears a little bigger and brighter thanks to its slightly closer position. During totality, the moon will look red because of sunlight scattering off Earth's atmosphere. That's why an eclipsed moon is sometimes known as a blood moon. In January, the full moon is also sometimes known as the wolf moon or great spirit moon.
The January 21 total lunar eclipse will be the last one until May 2021, and the last one visible from the United States until 2022.
The eclipse takes place when the full moon is at or near the closest point in its orbit to Earth. This means the moon is deeper inside the umbra shadow and therefore may appear darker.
The full Moon appeared bigger than normal because it was closer to the Earth - about 358,000 kilometers away - earning it the nickname "super Moon." Other monikers include a "Wolf Moon," a traditional way of coining an eclipse in the month of January, and a "Blood Moon" because of its rusty, red color. Hence the name for this year's event: a "super blood wolf Moon."
During a lunar eclipse, the Moon appears red because the light of the Sun no longer directly illuminates it, since Earth is passing in between the Moon and Sun. "The colour is due to Rayleigh scattering - where the Sun's blue light is scattered off molecules in Earth's atmosphere - which also happens at sunsets," explained the Royal Astronomical Society of Britain.
Total or partial lunar eclipses happen at least twice a year on average, Florent Deleflie, an astronomer at the Observatory of Paris-PSL says. It's just that they are not visible everywhere.
It's a rare event when a total lunar eclipse is visible on so many parts of the Earth's land mass, as is the case Monday.
Europeans last saw a total lunar eclipse in July 2018. The next chance for a glimpse at a lunar eclipse will be in 2022, but the entire continent won't be able to see the totality of a lunar eclipse again until 2029.
North Americans may get their next glimpse of a blood moon in 2021 along the West coast and 2022 on the East coast.