August 24, 2009
Every year, the Earth returns to the same point in its orbit where it was when you were born.
Morning Glory Clouds Over Australia
Birthday · August 24, 2009
A little universe, just for you
Your date.
Ready to give.
Free PNG · 1080 × 1350 · No account needed
Image rights and credit requirements apply when sharing or reusing imagery.
Date & occasion only
Change the year
APOD published August 24, 2009. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
What causes these long, strange clouds? No one is sure. A rare type of cloud known as a Morning Glory cloud can stretch 1,000 kilometers long and occur at altitudes up to two kilometers high. Although similar roll clouds have been seen at specific places across the world, the ones over Burketown, Queensland Australia occur predictably every spring. Long, horizontal, circulating tubes of air might form when flowing, moist, cooling air encounters an inversion layer, an atmospheric layer where air temperature atypically increases with height. These tubes and surrounding air could cause dangerous turbulence for airplanes when clear. Morning Glory clouds can reportedly achieve an airspeed of 60 kilometers per hour over a surface with little discernible wind. Pictured above, photographer Mick Petroff photographed some Morning Glory clouds from his airplane near the Gulf of Carpentaria, Australia.