These nacreous clouds appeared in the skies over the Bharati Indian Base Station in Antarctica on June 17, 2016.
The pastel polar stratospheric clouds floating over the frozen continent were absolutely stunning.
Bharati Station at 70 degrees south is just the place to get these wonderful filmy Polar Stratospheric Clouds.
Floating 9 to 16 miles high, these clouds, also known as mother of pearl, need incredibly cold temperatures below -85 Celsius to form.
The characteristic bright iridescent colors are produced by diffraction and interference when sunlight shines through tiny ice particles ~10µm across.
Lower in the atmosphere, fire rainbows can also shine with iridescent colours but never as vividly as nacreous clouds.
Is there another ozone depetion zone over Antarctica?