A Pale Blue Dot | Close Shave by a Tunguska Sized NEO, Friday | Cool Video of the Atmosphere Rippling Like a Pond

4:26 am in Uncategorized by john in sacramento

I have a few minutes, and thought I’d post something positive to kind of wash away all the negative, and give us a fresh perspective on things. First off the great Carl Sagan with his seminal essay Pale Blue Dot

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O.k. a N.E.O. is a Near Earth Object and that includes asteroids like 2012 DA14, which was discovered in … drumroll … 2012. Evidently, astronomers aren’t very creative in naming objects in the sky, like they were thousands of years ago ;-) Anyway, 2012 DA14 will pass us within 27,000 km’s, which about twice our own diameter.

Oh noes!!!111

Not really. Watch

More at Bad Astronomy
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So, I’m scrolling through Bad Astronomy and see this video

At about 1:50, that looks like ripples in a pond, seen from below, to me. One of the links given is this one, that says it’s from the shockwave of hypersonic flight. To me, my first thought was what happens when supersonic jets do high speed passes which causes the pressure to drop around the plane which causes a cone-like within the vortex, called the Prandtl-Glauert singularity

Now, check out this video for an example of that