A red 'blood moon' will appear in the sky on Thursday. Here's how to spot it.

• A total lunar eclipse will occur overnight Thursday, turning the moon's surface red.
• This blood moon turns red because all the sunsets and sunrises on Earth are projected onto it.
• Watch Earth's shadow "bite" the moon then change its color for the first time in two years.

When the moon gets spooky on Thursday night, don't panic. It's not an omen, it's just an eclipse.

Earth will cast its shadow across the moon, turning its surface red as our planet, our moon, and our sun align. That's why total lunar eclipses are sometimes called the "blood moon."

This will be the first total lunar eclipse in nearly two-and-a-half years.

The red color comes from the light of all the sunrises and sunsets happening across Earth.

That's because, even though the Earth is casting its shadow on the moon, the sun is still passing through Earth's atmosphere along the edge of that shadow. Those are all the regions where day is transitioning into night, and vice versa.

The atmosphere bends the sunlight toward the moon. Blue light gets scattered in the atmosphere, which is why the sky is blue. Only the red portion of the light spectrum cuts through to reach the lunar surface.

"It's as if all the world's sunrises and sunsets are projected onto the moon," NASA wrote in a blog post.

When and how to see the blood moon

Depending on what time zone you're in, the eclipse will occur the evening of March 13th or very early on the morning of March 14th.

The Earth's shadow will begin to creep over the moon, creating a partial lunar eclipse, at 1:09 a.m. ET.

To the naked eye, according to NASA, "it looks like a bite is being taken out of the lunar disk."

The parts of the moon that are eclipsed will be dark until 2:26 a.m. ET, when the eclipse becomes total. Earth's shadow will completely swallow the moon and cast it in red.

Use binoculars or a telescope to see the eclipse more clearly and peer at the moon's briefly-red craters. For taking photos, NASA recommends putting your phone on a tripod and setting the camera to take long exposures of at least a few seconds.

Totality will last a little over an hour, until 3:31 a.m. ET when the Earth's shadow continues passing over, creating several more hours of partial eclipse. The moon will be completely back to normal by 6 a.m.

If you miss it, don't worry because this is the first of three. There will be another total lunar eclipse in September, and then another in March.