Thursday, August 13, 2015

Clouds And Shadows And A Glory

One would think that pictures from the plane in an out of Anchorage would get old.   But even though I've lived here for almost 40 years now and I'm still amazed by how the mountain views change as the light and shadows change.  So I shouldn't be surprised by a seeing Cook Inlet differently as we flew into Anchorage Monday.

The battery on the bigger camera died as we got over Turnagain Arm, so these are from my little Powershot.    Below is the road into Girdwood and the mudflats.

As we flew in and out of the clouds, our shadow came and went, sometimes circled by a rainbow.  This actually has a name - a glory. - ( I needed to check on it before posting.)  According to Wikipedia:
"A glory is an optical phenomenon that resembles an iconic saint's halo about the shadow of the observer's head, caused by light of the Sun or (more rarely) the Moon interacting with the tiny water droplets that make up mist or clouds. The glory consists of one or more concentric, successively dimmer rings, each of which is red on the outside and bluish towards the centre. The effect is believed to happen due to classical wave tunneling, when light nearby a droplet tunnels through air inside the droplet and, in the case of a glory, is emitted backwards due to resonance effects.[1]"
"The scientific explanation is still the subject of debates and research. In 1947, the Dutch astronomer Hendrik van de Hulst suggested that surface waves are involved. He speculated that the colored rings of the glory are caused by two-ray interference between "short" and "long" path surface waves—which are generated by light rays entering the droplets at diametrically opposite points (both rays suffer one internal reflection).[3] A new theory by Brazilian physicist Herch Moysés Nussenzveig, however, suggests that the light energy beamed back by a glory originates mostly from classical wave tunneling, which is when light rays that missed a droplet can still transfer energy into it.[1]"

After flying over south Anchorage, we veered west for a slow loop back to the runway.  Lots of cloud shadows on the water.

And then as we closed in on the runway, the light changed again. 

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