A 'Da Vinci glow' casts a ghostly shine on the moon this week. Here's when to catch it.

A 2.5 percent waning gibbous moon illuminated by earthshine rises behind the Empire State Building before sunrise in New York City on September 24, 2022, as seen from Hoboken, New Jersey.
Here's how and when to see the ghostly phenomenon of "Da Vinci glow."Gary Hershorn/Getty Images
  • The "Da Vinci glow" phenomenon will be visible on the moon this week.

  • The ghostly gleam, also called "Earthshine," is reflected sunlight from Earth.

  • Here are the best days and times to see the "Da Vinci glow," according to Live Science.

This week a ghostly shine will appear on the moon, glowing on the edge of the lunar body. The phenomenon is known as the "Da Vinci glow," or "Earthshine."

Right now, the moon is a thin crescent, barely visible in the night sky. Thanks to the "Da Vinci glow," however, you can see the entire moon as a faint glimmer.

But this phenomenon is only visible during a precious time window shortly before sunrise and after sunset.

What causes Earthshine?

When the sun, Earth, and moon are positioned just right, sunlight bounces off all the snow, ice, and clouds on our planet to light up the dark side of the moon that we would otherwise be unable to see.

That's why the phenomenon is called Earthshine because it is the moon reflecting our light back to us.

Leonardo da Vinci documented this eerie gleam 500 years ago. The Da Vinci glow usually peaks in spring, as the Northern Hemisphere tilts toward the sun, with snow and ice still covering the Arctic, according to NASA.

That makes Earth more reflective, which is why our planet is casting its glow onto the moon early this week and next weekend.

moon from earth
Earthshine on the moon.NASA Earth Observatory

Earthshine has dimmed over the past two decades, however, due to rising global temperatures that are warming the Pacific Ocean and reducing low-lying cloud cover there, according to a 2021 study of measurements from the Big Bear Solar Observatory.

When to see the Da Vinci glow on the moon

The new moon on Friday will be practically invisible, lost in the sun's glare, so plan to catch the Da Vinci glow before or after that. The best time to see it varies by day.

If you're an early riser, you can spot the glow on the moon in the eastern sky during the hour before sunrise on Wednesday, according to Live Science.

If you miss this week's opportunity, however, you can still catch it, starting next weekend, when the moon will be waxing, aka growing, from a thin crescent toward a full moon.

In the hour after sunset in the western sky, here are the best days to catch the Da Vinci glow next weekend and into early next week:

  • Sunday, May 21: 5% of the moon will be visible as a slim crescent

  • Monday, May 22: 10% of the moon will be visible as the crescent fills in a little more

  • Tuesday, May 23: 17% of the moon will be visible, looking more like a nearly-devoured cookie

The phenomenon is best seen without equipment, but viewers can also watch the Da Vinci glow with some binoculars or a small telescope.

It looks cool from here, but basking in the glow of Earthshine on the moon itself would be a glorious experience.

"An astronaut standing on the moon after sunset would see a spectacular, fully lit Earth," according to NASA.

For now, we'll all have to be content with seeing the gleam of Earthshine from afar.

Read the original article on Business Insider