2019 June 26
Noctilucent Clouds, Reflections, and Silhouettes
Image Credit & Copyright:
Sometimes it's night on the ground but day in the air.
As the Earth rotates to eclipse the Sun,
sunset rises up from the ground.
Therefore, at sunset on the ground, sunlight still shines on
Under usual circumstances, a
might be visible, but unusual
noctilucent clouds float so high up they
can be seen well after dark.
Normally too dim to be seen,
they may become
visible just after sunset during the summer when illuminated by sunlight from below.
are the highest clouds known and thought to be part of
polar mesospheric clouds.
Featured here as they appeared two weeks ago,
a network of
noctilucent clouds was captured not only in the distant sky but in reflection from a small lake just north of
Netherlands, with trees in stark
silhouette across the horizon.
noctilucent clouds continue to appear over much of northern
noctilucent clouds has been discovered only over the past decade,
while how they form and evolve remains a
topic of active research.