You may have noticed the Moon showing a ghostly glow recently, as a faint light illuminates the normally unlit part of the Moon’s surface. This is a phenomenon called Earthshine, and it can be a breathtaking sight, not to mention a great opportunity for lunar photography.
In this article, we explain when you can see this lunar flare, what causes it, and why it was named after one of the most famous musicians of all time.
You can also make the most of the clear nights this year with ours UK full moon calendar An astronomy guide for beginners.
When can I see the brightness of the Earth?
Weather permitting, you can see the earth’s brightness this evening, May 23rdafter sunset (8:56 p.m. GMT in London, 8:13 p.m. EST in New York City).
Earth’s brightness can be seen in the morning a few days before the new moon, and in the evening a few days after the new moon. You may have already caught a glimpse of it before sunrise on May 17 during the waning crescent phase, but if you didn’t feel like dragging yourself out of bed at that hour, we’ve got another chance during waxing Crescent moon phase.
Here are the next opportunities to watch the Earth’s brilliance:
- May 23: 15.5 percent lit by the waxing crescent moon
“Take a look on the evening of May 23, and you’ll be able to see the crescent moon between the bright planet Venus and the star Pollux, and the red planet Mars to the left of the couple,” she advises. Dr. Darren PasquilLecturer in Astronomy at the University of Sussex.
This phenomenon appears more clearly during the waxing or waning crescent phase, because the illuminated part of the moon is thinner, allowing a larger part of the dark moon to be illuminated by the brightness of the Earth.
It’s the perfect time of year for viewing, since during spring the northern hemisphere is tilted toward the sun, while at higher latitudes, winter’s snow and ice still provide ground cover. Snow and ice reflect more light than darker-colored plants and water (for example, snow and ice have a higher albedo), so we get a more pronounced terrestrial brightness.
Although you might expect Earth’s brightness to be brighter during the winter months when snow cover and ice are prolific, the amount of light that reaches the North Pole is much less, so Earth’s brightness is not as eventful during the winter.
Bottom line: get out and watch it while you can!
What exactly is Earthshine?
Earthshine appears as a soft, subtle glow on the unlit, or “night,” part of the Moon during specific phases. This is when the delicate, but somewhat ghostly, shape of the full moon is nestled in the arc of a bright crescent moon, a beautiful sight on these early summer nights.
Also known as da Vinci glow, intensity The brightness of the Earth can vary depending on certain factorssuch as weather conditions, ground reflectance, and the observer’s location.
Just be aware of the popular media that says “the dark side of the moon is visible” because this is not true; The dark side of the Moon is facing away from us.
Because the Moon is locked in a tidbit, we will never be able to see the dark side of the Moon from our vantage point here on Earth. Instead, we can see not lit part.
What are the reasons for this?
Earthshine is also known as the Da Vinci glow, ashen glow, or rather romantically, “the old moon in the arms of the new moon.” It is caused by sunlight reflecting off the Earth’s surface and then reflecting back on the Moon.
“Like all planets and moons, the Earth does not emit light – it only reflects sunlight,” explains Pasquel.
“Reflected sunlight can be seen illuminating the dark part of the moon for a few days on either side of the new moon, when the moon appears as a crescent moon in the evening or morning sky.
“The crescent moon is caused by the bright sun’s rays directly illuminating the moon, while the darker part of the moon is dimly lit by earth’s rays – sunlight reflecting off the earth to gently illuminate the moon.”
Earth’s brightness occurs during the phase in the lunar cycle when it illuminates only the thin crescent of the moon direct Sunlight – whether in the waxing or waning phase.
As for the part of the moon that is not illuminated by direct sunlight, this is the part that we see as a ghostly glow. As we all know, sunlight reaches the earth and illuminates its surface. But this is not limited to land masses, as it also includes clouds, oceans and the atmosphere.
Then some of that light is scattered, scattered, and reflected back into space. Part of this reflected light travels toward the Moon, landing on the unlit part, the lunar night side.
The Moon, despite having a non-reflective surface, bounces this light reflected off the Earth. It is this phenomenon that results in a faint glow on the unlit part of the moon, providing a subtle illumination of the dimly lit lunar surface.
What affects it?
The appearance and intensity of the Earth’s brightness is affected by several factors, including the Earth’s cloud cover, the composition of the atmosphere, and the angle of reflection of sunlight from our planet on the Moon. These factors can cause slight differences in the brightness and color of the Earth’s brightness, making it different every time.
Earth’s atmosphere, for example, plays an important role in shaping the appearance of Earth’s radiance. As light from the Sun passes through the atmosphere, it undergoes scattering and absorption, with different wavelengths being affected to varying degrees. This filtering in the atmosphere affects the color and intensity of the Earth’s brightness, and it is this light that is ultimately reflected back to the Moon.
Different ground cover will reflect different amounts of light; For example, the ground reflects about 10-25 percent, while clouds reflect about 50 percent of the light.
Why is it called the Da Vinci glow?
In the early 16th century, Renaissance musician Leonardo da Vinci turned his thoughts to unraveling the mystery of this strange, otherworldly glow. He made detailed sketches and drawings of the moon, and while da Vinci did not coin the term himself, these observations have led to its association with his name.
His notebooks contained a drawing depicting the brilliance of the Earth, which is now celebrated at Codex ListerA collection of da Vinci’s scientific writings. Although you’ll need patience if you want to read the manuscript yourself, as da Vinci recorded his notes in his distinctive mirror writing; From back to front italian.
What equipment do I need to see the Da Vinci glow?
Aside from always wanting clear skies, no special equipment is required. If you have a few things handy, though it’s not necessary, using binoculars or a telescope can help you pinpoint features you wouldn’t normally be able to see on the lunar surface, and keep a close eye on subtle differences in brightness.
You might want to try drawing the moon on dark paper with chalk, pastels, or pencils.
Will climate change affect our ability to see it?
potentially. Researchers looking at terrestrial albedo found it Rising temperatures may result in less intense groundshine.
As the oceans warmed, they found that fewer low clouds formed over the eastern Pacific Ocean, west of the Big Bear Solar Observatory in California where they were taking measurements. This decrease in cloud cover led to a slight decrease in the Earth’s albedo (reflectance), which subsequently affected the intensity of Da Vinci’s glow.
About our expert
Dr Darren Paskill is an Outreach Officer and Lecturer in the Department of Physics and Astronomy at the University of Sussex. He has previously lectured at the Royal Observatory Greenwich, where he also started the annual Astronomical Photographer of the Year competition.
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