Blood moon: Longest lunar eclipse of the century is coming this week

Doyle Rice | USA TODAY

Show Caption Hide Caption The upcoming blood moon will be the longest lunar eclipse this century We aren’t strangers to seeing the moon in the sky, but the Blood Moon that’s set to take place in July is going to be a little different.

First, the good news: At nearly two hours long, this week's lunar eclipse will be the longest of the century.

The bad news: North America is the only continent on Earth where it won't be visible.

The best views will be in Africa and Asia, but folks in Europe, South America and Australia will still get partial views.

The eclipse will occur on the night of July 27 into the early hours of July 28. According to EarthSky, it's the longest total lunar eclipse of the 21st century. "The total phase of the eclipse – called the totality – spans 1 hour 42 minutes and 57 seconds," said EarthSky's Bruce McClure.

During the eclipse, the moon will appear red, giving it the nickname "blood moon."

A total lunar eclipse occurs when the moon and the sun are on exact opposite sides of Earth, according to NASA. When this happens, Earth blocks the sunlight that normally reaches the moon. Instead of that sunlight hitting the moon’s surface, Earth's shadow falls on it.

Although the moon is in Earth's shadow, some sunlight still reaches the moon. The sunlight passes through Earth's atmosphere, which causes Earth’s atmosphere to filter out most of the blue light.

This makes the moon appear red to people on Earth.

An added treat next week: July's total lunar eclipse occurs on the same day the planet Mars reaches its opposition, when it will shine at its best in the night sky, according to Space.com. A Mars opposition is when the Earth lies between Mars and the sun, making the sun and Mars appear in opposite directions as viewed from the Earth.

This month, Mars will be at its closest to Earth since 2003.

The next lunar eclipse that will be visible in North America will be next winter: Jan. 21, 2019. Skywatchers will have to bundle up for that one.

As for a solar eclipse, you've got a longer wait. Although there are three partial solar eclipses this year, none are visible in the U.S.

The next total eclipse of the sun visible in the U.S. will occur on April 8, 2024. That gives you plenty of time to stock up on those eclipse glasses you tossed after the big eclipse last year.