Wow! Look at these photos of northern lights over the Mackinac Bridge last Friday night/Saturday morning. Taken by Peggy Sue Zinn of photographyofpeggysuezinn.com.
A tad chilly
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Apr 15, 2015
0
#2403
Joseph-S wrote:
Ok then, going by your weather records, on what date are you statistically most likely to get the first day of snowfall later this year in your area?
I had to ask the NWS Gaylord office for these dates. It's not obvious how/where to look it up. The average date for the first measurable snow in the Soo is October 21, and the average date for the last measurable snow is April 24. Still 9 days off for that "ending" date!
Cystem_Phailure wrote:
Joseph-S wrote:
Ok then, going by your weather records, on what date are you statistically most likely to get the first day of snowfall later this year in your area?
I had to ask the NWS Gaylord office for these dates. It's not obvious how/where to look it up. The average date for the first measurable snow in the Soo is October 21, and the average date for the last measurable snow is April 24. Still 9 days off for that "ending" date!
I knew if anybody could find out about something like that, it would be you, the weather guru! 
Nice pictures!
Apr 16, 2015
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#2406
The 1st photo is the best image available for Pluto right now. The 2nd image is what Earth would look like at the same (lack of) resolution.
Interesting!!!!!!!!!
Apr 18, 2015
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#2408
Breaking up fairly fast now. This is quite a bit of change from the image I posted just 4 days ago. The upper channel of the St. Mary's is represented on the chart as still all solid, but in front of the Phailure asylum the water has been open most of the way across for the past couple days. That can still fill in again with loose ice blown in from Whitefish Bay-- it only takes a few hours and a lot of ice can move around.
Apr 20, 2015
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#2409
A 1995 photo of a Lockheed SR-71B Blackbird (the "B" was the 2-seater trainer version) in the vicinity of Edwards, California. This was one of two SR-71s (the other a single-seater SR-71A) transferred to NASA for research use when the Air Force shut down the SR-71 program. NASA still retains their two Blackbirds but has not flown them since 1999.
NASA research with the SR-71s included thermal studies (on the plane surfaces at Mach 3), sonic boom mitigation, and the use of lasers to collect air data during flight (for airspeed and altitude like sideslip, angle of attack, etc.). There were also flights with an upward-directed ultraviolet camera for studies of celestial targets at wavelengths blocked by the atmosphere.
Acknowledged performance maximums for the SR-71:
- speed: Mach 3.3 (2200+ mph; 3500+ kph)
- ceiling: 85,000 feet
- range: 3300+ miles (5400 km)
- climb rate: 11,820 feet/minute (much lower than the top climb performers)
and all that with a plane designed in the early 1960's and last produced in May of 1967.
The SR-71 records for speed and altitude (sustained flight) still stand, officially (rumors abound among the conspiracy crowd of various craft with better performance, but all completely undocumented).
Wow. Isn't 85,000' near what is considered our atmosphere?
(mach 3 is incredible, too.)
Apr 20, 2015
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#2411
There are lots of definitions of where the atmosphere peters out, though the SR-71 used normal air-breathing engines, so there was enough atmosphere up there for power and for sustained controlled flight.
That guy from Google that set the record for the highest parachute jump last October bailed out of the balloon at 135,000 feet-- I doubt there was enough air for the balloon to go much higher.
Seven X-15 flights surpassed the 62 kilometer (~327,000 feet) altitude necessary to qualify the pilots as astronauts. However, the X-15 was rocket-powered and not restricted to atmospheric flight.
Apr 20, 2015
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#2412
BTW, those incredible speeds weren't just momentary sprints. The SR-71's engines ran at their maximum efficiency at about Mach 3.2, which was considered its normal cruising speed. Speeds higher than that were obtained mainly from afterburner thrust rather than engine thrust. It could fly supersonic for about 90 minutes before needing in-flight refueling.
One sneeze while flying at that speed and you'd find yourself two continents over from where you were intending to go. 
Apr 20, 2015
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#2414
I guess that's one advantage of flying that high-- not much in the way of obstacles to hit if you get distracted for a couple seconds. Even at Mach 3.3 in a straight-down dive starting from 85,000 feet, it would take 23 seconds to hit the ground. 
I did some minor maintenance on the SR-71 once when I was in the Air Force.
Apr 21, 2015
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#2416
Did you work on the aircraft itself or the surveillance payload?
Aircraft itself.
Washing the windows?
Apr 22, 2015
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#2419
Rocket fans might like to skim these lists of both launch histories and upcoming scheduled launch manifests for the Atlas V and Delta IV rockets.
http://spaceflightnow.com/2015/04/21/stats-atlas-5-and-delta-4-histories-and-backlogs-updated-april-20/
- Delta IV rocket (left image): first launch in March 2003, 28 total launches with no failures
- Atlas V rocket (right image): first launch in August 2002, 53 total launches with no failures
Current plans call for the Vulcan rocket being developed to replace both the Atlas V and Delta IV by about 2019.
Apr 23, 2015
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#2420
It's been back to snow showers the past couple days, though only about a half inch each day. Yesterday's high T was 33 F, a return to reality after 10 straight days of high Ts ranging from 48 F to 63 F.
It will be a struggle to get above freezing today too, but it doesn't look like there will be new snow flurries.
My hero Buzz is at the Space Symposium at Colorado Springs and points out that he draws more attention than the bartender who's handing out free beer.
I like that Buzz is the only guy there who has taken off his jacket.
Of course, the guys in the military togs aren't allowed to (I don't think).