Earthshine

[Sunshine]

Though I am aware of what causes earthshine, last night while observing the moon I couldn't help notice just how bright it was. It (earthshine) appeared to be brighter than I ever did see, I was able to make out details within it that i never thought was possible, why so much brighter some days than others? atmospheric conditions? more ocean area facing moon, reflecting more light than land masses?.

Edited May 27, 2020 by Sunshine

[Knight of Clear Skies]

Good question, I also noticed it was particularly bright last night. I found an explanation here.

"The phenomenon is called earthshine. It tends to be brightest between April and June, though it does occur at other times of the year. "

"Earthshine varies in strength throughout the year, since the light reflected from the Earth varies. Earth’s reflected light (albedo) is brightest in the Northern Hemisphere spring with a second, slightly smaller peak in the Southern Hemisphere spring.

Satellite measurements of energy reflected from the Arctic provide a picture of why earthshine peaks in the spring. During this period, the Northern Hemisphere is tilted towards the Sun and winter snow and ice are still on the ground in the higher latitudes. Because snow and ice reflect more light than vegetation or water, the spring is brighter than the summer or autumn, when there is much less snow and ice. During the winter, the Arctic receives very little sunlight and reflects less light. Clouds and sea ice contribute to the peak in the Southern Hemisphere."

You were thinking along the right lines but ice is the biggest factor. (So I guess in coming decades it will be less bright.)

Edited May 28, 2020 by Knight of Clear Skies

[Sunshine]

Thanks! while brainstorming it without actually googling it (i like asking fellow members first) i kept gravitating towards what features on earth are most reflective but, totally overlooked the poles.