Earthshine to Illuminate the Moon Tonight: Rare Celestial Event Visible Across the Sky

Crescent Moon to Glow With Earth’s Reflected Light on the Night of Akshaya Tritiya

Bhopal, April 30 — Skywatchers are in for a celestial treat this evening as a rare phenomenon called “Earthshine” will make the crescent Moon appear to glow more brightly in the night sky. The event coincides with Akshaya Tritiya, an auspicious day in Hindu tradition, adding spiritual significance to a scientifically fascinating occurrence.

Renowned science communicator and National Award recipient Sarika Gharu explained that the Moon will appear as a glowing crescent in the western sky around sunset. Interestingly, while only a small portion (approximately 9.9%) of the Moon will be directly illuminated by the Sun, the rest of its dark surface will also be faintly visible due to light reflected from Earth.

What Is Earthshine?

The phenomenon, known as Earthshine, occurs when sunlight reflects off the Earth’s surface and illuminates the Moon’s otherwise dark side. This happens because the Earth reflects about 30% of sunlight, compared to the Moon’s 12%, making Earth an effective secondary light source for the lunar surface.

“This glow allows the unlit portion of the Moon to become subtly visible to the naked eye, without any telescopic aid,” said Sarika Gharu.

Historical Roots: Da Vinci’s Observation

Earthshine is also known as the “Da Vinci Glow”, named after Leonardo da Vinci, who first described and sketched the effect around 1510. The event typically occurs twice a year, making tonight’s viewing a rare opportunity for astronomy enthusiasts and casual observers alike.

According to astronomical data, the Moon will be approximately 363,897 kilometers from Earth during this event and will be visible until around 9:30 PM, after which it will set.

How and When to Watch

• Time: Around sunset until 9:30 PM

• Direction: Western sky

• Visibility: Easily observable with the naked eye, no equipment needed

• Moon Shape: Crescent (sickle-shaped) with a faint outline of the full disc

Sarika added, “When you look at the Moon tonight, remember—it’s glowing because of the very Earth you’re standing on. That’s the beauty of Earthshine.”