Thursday, March 29, 2007

Space Debris vs. Jet Plane: Debunked

Surely you've read the news story about a Chilean jet narrowly missing space debris near New Zealand. I can safely say, as the story is written, it didn't happen.

Meteors are notoriously described with outrageously close distances-- "extinguished below the horizon", "no more than 3 - 5 thousand feet high when directly above me", etc., despite the luminous portion of the meteor flight starting at 120-75km altitude, and ending by 20km altitude. How did the pilot see this object, if it was no longer luminous, at his flight elevation? Let alone "knowing" it was only five miles away from the plane. Likely, he had received notice that the Russians were deorbiting a satellite that day, albeit twelve hours later, and saw the meteor and mistakenly claims near-disaster.

Pilots have long mistaken meteors as being close--the grandfather of meteoritics,
Harvey H. Nininger, called their reports "humorous at best". In fact, you should read that entire article:

During Nininger's time a number of airpilots reported having to take evasive steps to prevent collisions with falling meteors. One such newspaper reported an startling account of how a resourceful pilot battled a shower of meteors by making a serious of dips and swerves to avoid the incoming falling meteors saving himself, his eleven passengers, as well as the aircraft. One other pilot was said to have dipped his right wing to avoid a similar collision of a meteor which happened in Nebraska. Yet another pilot near Cheyenne Wyoming said he narrowly escaped injury when en-countering one of those pestiferous fiery projectiles which threaten to side swipe him from the left. He "ducked", however and the missile sailed by, leaving him unharmed.
Nininger knew of the fall of those cited above and concluded that the second pilot who thought he saw the meteor below him, plotted the meteor height at the burnout point at about 17 miles high, above the northeastern New Mexico soil. The second pilot who saw the same meteor fall was slightly more than a hundred miles from it at its nearest approach. The pilot over Nebraska that dipped his wing to avoid collision was 68 miles south of the line over which the dreaded missile was speeding at an elevation of approximately 20 miles.

Pilots in the 1920's were having difficulty giving range to bright objects--what makes anyone think they still aren't?

Thursday, March 22, 2007

The moon and Venus

The waxing crescent Moon and Venus appeared in the unusually clear evening skies at Chicago on Tuesday.

Tuesday, March 20, 2007

Mars photo filler

I've been bad about posting, so here is an image I assembled from a video taken of Mars on July 30th, 2003. The prominent peninsula to the bottom of Mars is Syrtis Major, the darkest feature on Mars visible from Earth. It's a region scoured clean of any dust, leaving only dark basaltic rock exposed. Extending to the right is Sinus Meridiani, location of the still running Mars Opportunity rover. The bright polar cap is the South Polar Cap. The color fringes are real--real on Earth, that is. Mars was low in the sky, and the Earth's atmosphere acted like a weak lens and bent the colors slightly differently, enough to create fringes (North is to the bottom in the image). Here's a map of the landing sites, and an interactive Google Mars link.

Monday, March 12, 2007

Tvashtar on Io

The gorgeous plumes of Ionian volcanos rise into the sunlight on this image taken from the New Horizons spacecraft as it sped past Jupiter. The darkside of Io is seen via "Joveglow". Tvashtar and a seemingly asymmetric plume is at top.

Seen via tingilinde and many other sites -- see more images here

Thursday, March 08, 2007

More snow shadows

Ken commented on the appearence of snow shadows in a Pennsylvanian forest and made an interesting insight: "the snow can actually be considered a very slow acting photographic medium". Which is honestly so true. I also posted two new snow shadows from today.

Monday, March 05, 2007

The lunar eclipse

Chicago got a mostly cloudy eclipse--we never saw it fully eclipsed and only had glimpses as the Moon left the Earth's shadow. Here's a sample of what it looked like from Ryerson Observatory: