If you live in Western Australia, Europe, Asia, or all of Africa, you should keep the night of July 27 free. And that’s because you’re in for the longest total lunar eclipse of the 21st century. That’s a whole hour and 43 minutes of Earth’s shadow blacking out the moon, which is a lot more than usual.
How much longer? Well the last time we had a total lunar eclipse was January 31, which lasted a comparatively short hour and 16 minutes.
Now, to be clear, a lunar eclipse is a very different (and more regular) event than a solar eclipse. A lunar eclipse happens when the Sun, Earth, and Moon all align, which places the Earth between the Sun and Moon. And that casts the Earth’s shadow over the Moon.
In the case of July 27, the eclipse will take a particularly long time because the Moon will be moving through the darkest part of the Earth’s shadow. This region, known as the umbra, will lend the Moon a dusty red colour—turning it into what's known as a Blood Moon. So not only will it be the longest total lunar eclipse of the century, it’ll also be red.
The only downside to all of this is that if you’re in North America, you’ll miss out. And that’s because the planet will be facing in the wrong direction when it aligns with the Moon. But for anyone in the more easterly parts of South America, you’ll get the last stages of the eclipse just after sunset on July 27.