Starship Asterisk*

Chris Peterson wrote:
Is the bright spot in the video actually a sundog (that is, a reflection from aligned ice crystals, 22° from the Sun), or a reflection from an isolated patch of ice crystals? I've seen both (but not dancing), and since I can't tell where in this image the Sun actually is, I can't tell if this is really a sundog.

http://www.theblaze.com/blog/2011/11/07/how-scary-is-this-2/ wrote:

[size=200][color=#FF0000]22° from the Sun[/color][/size] :?:

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<<Guinness Book of World Records holder John Cassidy performs a balloon act for First Lady Michelle Obama in the Diplomatic Reception Room of the White House, Oct. 11, 2011. Cassidy performed for kids on the South Lawn before the First Lady launched a challenge to break the Guinness World Records title for the most people doing jumping jacks in a 24-hour period.>>

RonDavis wrote:A related phenomenon is that often during a thunderstorm, after a nearby lightning stroke, the rainfall suddenly becomes more intense. I figure that's because the raindrops are carrying negative charge down to the ground, building up positive charge in the clouds. The drops fall against that field, as makes sense because they are increasing the energy in the electric field. A lightning stroke between sky and ground drains off some of that charge and reduces the field, thus causing the drops to fall faster. Since a typical change in the electric field can have that much effect on many tonnes of water, I can well believe that it can rapidly affect the orientation of ice crystals in a cloud.

Barry Vincent wrote:Fascinating ,but how come the clouds don't seem to be moving ?
One would think that over the duration of the video there would be some change
in the cloud shapes.

Chris Peterson wrote:Is the bright spot in the video actually a sundog

Chris Peterson wrote:I'd think that in general, if you were interested in this phenomenon, you'd want to look for reflective areas around thunderclouds, not usually at sundogs (which aren't usually present when there are thunderclouds).

PParke wrote:The NWS is in the process of developing some products from this system that compares vertical polarization with horizontal polarization of both ice crystals and precipitation. So far, NWS research has found sharp bands of contrasting values where dual-polarized radar beams intersect ice crystals around the tops of thunderstorms. These ice crystals have been found to change orientation suddenly and across short distances due to lightning discharges.

Guest wrote:IMHO, and in concordance with seasoned atmospheric optics observers, I must say the jumping sensation CANNOT be a sundog,

Guest wrote: as there is no color at all. My question would be, whether the vid has been taken through a window with maybe a water drop on top to produce an image ghost.

katy wrote:What the heck is it my computer blocks youtube CAN ANYONE TELL ME WHAT IT LOOKS LIKE BECAUSE I LIKE TO SEE THE ASTRONOMY PICTURE OF THE DAY EVERYDAY HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

oldastronomer wrote:WAY COOL! It's not very often that APOD actually teaches us something new--or at least something we didn't know before. Keep up the great work.

katy wrote:What the heck is it my computer blocks youtube CAN ANYONE TELL ME WHAT IT LOOKS LIKE BECAUSE I LIKE TO SEE THE ASTRONOMY PICTURE OF THE DAY EVERYDAY HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

wbeaty wrote:The video shows bright bands ?cirrus? next to a thunderhead, and the bright parts are jumping around every few seconds. It's probably one of these seen from below: http://apod.nasa.gov/apod/ap110824.html

wbeaty wrote:Read the main entry again, I believe you've missed the entire point: the cloud in the videos aren't jumping. The sudden motions in all the various different videos are obviously not motions of clouds.

The real question is, why aren't there hundreds of videotaped events like this, rather than just four? One obvious possibility: the bright patch caused by electrically-aligned crystals would only be visible over a fairly small angle, so the sun would have to be at the right height above horizon, and the eyewitnesses would have to be in the right place on the ground relative to the reflective cloud. And of course the cap-cloud would have to contain crystals.

radii wrote:Someone from the ground is aiming a beam up there causing temperature variants and changes in the clouds and intense reflections - probably some college kids at a university in the astronomy dept.