Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2016 August 19 
Posted on 08/19/2016 5:58:23 AM PDT by ThomasMore
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2016 August 19
Explanation: On the night of August 12, this bright Perseid meteor flashed above volcanic Sunset Crater National Monument, Arizona, USA, planet Earth. Streaking along the summer Milky Way, its initial color is likely due to the shower meteor's characteristically high speed. Entering at 60 kilometers per second, Perseid meteors are capable of exciting green emission from oxygen atoms while passing through the tenuous atmosphere at high altitudes. Also characteristic of bright meteors, this Perseid left a visibly glowing persistent train. Its evolution is seen over a three minute sequence (left to right) spanning the bottom of the frame. The camera ultimately captured a dramatic timelapse video of the twisting, drifting
(Excerpt) Read more at apod.nasa.gov ...
Kinetic Energy of a perseid the size of a basketball is phenomenal...
ENERGY = 1/2 * mass * velocity ^2
ENERGY = 1/2 * 100 lbs * 60 km/s ^2
19.514 tons TNT
... an 18" rock is about 300 lbs and would yield a nearly 60 ton TNT explosion at this incredible speed.
... a 3 foot by 4 foot rock will weigh in at about 5000 lbs and at this speed would result in nearly a 1 kiloton explosion. (suitcase nuclear)
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I went out for an hour that night and saw 8. I thought that was pretty good. A couple of them looked like that.
Saw two in Tucson area about about 8:30 PM 5 minutes apart moving from NNE to SSW. They looked so low I was waiting for a sonic boom.
Good thing they’re all very small.
I was out from 3 to 4 a.m. Was going to be out earlier for longer. Just didn’t make it. This was the first time in several years we had clear skies.
Years ago while watching the Perseids, I heard one "sizzle" in the atmosphere. It was really cool.
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