What is the 'black moon' and where can you see it?

A rare "black moon" will fill the skies across the western hemisphere tomorrow night.

But while a "black moon rising" may sound ominous, it "is unlikely to signal the end of the world, despite the concerns of some doomsayers", says the Daily Telegraph.

What is a black moon?

The Week

Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.

SUBSCRIBE & SAVE

Sign up for The Week's Free Newsletters

From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.

From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.

Sign up

Each month, the moon goes through several phases. A "new" moon occurs when the satellite's orbit takes it between Earth and the sun and its unilluminated side is facing us, leaving just a slim crescent showing. A "full" moon occurs when it is completely lit up and we see a giant circle.

Usually, these occur only once a month, but because there's a slight differential between the moon's phases and the Gregorian calendar, some months can have two, says National Geographic.

"A second full moon in a single calendar month is sometimes called a blue moon," says Joe Rao from Space. "A black moon is supposedly the flip side of a blue moon; the second new moon in a single calendar month.

The last black moon was in March 2014. Tomorrow's showing will be the last one until 2019.

How can you see it?

Those "hoping to spot the black moon from their window this weekend could be left feeling a little disappointed", says The Sun.

The lunar display will take place in the early hours of Saturday, at 1:11am GMT for those in the western hemisphere. However, low-lying cloud in the UK, as well as the very dark nature of the night sky, will render the moon invisible to most stargazers.

"It will just be very dark," concludes the Telegraph.