Once-in-a-lifetime lunar eclipse to occur on Thursday night

Lunar eclipses occur when Earth's shadow blocks the sun's light, which otherwise reflects off the moon. Photo: NASA

PARK CITY, Utah — An estimated six-hour-long lunar eclipse is set to take place on Thursday night.

A lunar eclipse is when the sun, earth, and moon are almost exactly aligned. Earth blocks the light of the sun from hitting the moon.

“During a lunar eclipse, the Moon turns red because the only sunlight reaching the Moon passes through Earth’s atmosphere,” NASA said.

“The more dust or clouds in Earth’s atmosphere during the eclipse, the redder the Moon will appear. It’s as if all the world’s sunrises and sunsets are projected onto the Moon.”

Around 2 a.m. MST Friday morning, 97% of the moon’s surface will be covered by the umbral shadow — which is the darkest part of the earth’s shadow.

The next longest lunar eclipse will not appear until the year 2669, according to Time and Date.

The problem in Park City? Mostly cloudy skies are in the forecast.