Search found 9 matches
- Thu Oct 30, 2014 12:26 am
- Forum: Open Space: Discuss Anything
- Topic: ISS with Progress in trail
- Replies: 0
- Views: 341
ISS with Progress in trail
Saw an amazing sight last night here in Chiang Mai Thailand as the ISS made a pass directly overhead. Progress was clearly visible behind it working on catching up. Does anyone have historic tracking information on Progress? I am curious to know how far apart they were when they went overhead. Never...
- Tue Nov 12, 2013 6:49 am
- Forum: The Library: Information Desk and Educational Resources
- Topic: Rentry Physics
- Replies: 22
- Views: 82842
Re: Rentry Physics
So still no definitive answer here. As Lord Kelvin once said, "If you can not express the worth of your work with numbers, it is of a meager and unsatisfactory kind." I like the post using an assumption of 1kg, but the little balsa gliders I am referring to are about .5 ounce in weight, so...
- Mon Nov 04, 2013 1:54 pm
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: ISON question
- Replies: 7
- Views: 1271
Re: ISON question
Thanks for that neufer. That gives hope for a good show coming up. It is hard for me to conceive that evaporative cooling can last long enough that close to the sun, but the physics laws rule.
- Mon Nov 04, 2013 6:27 am
- Forum: The Asterisk Café: Discuss Anything Astronomy Related
- Topic: ISON question
- Replies: 7
- Views: 1271
Re: ISON question
It seems no one is certain what will happen as it passes something like a sun's diameter from the sun. I would think all the ice will be vaporized, causing all kinds of strange dynamics. This is one of the most exciting things to happen in astronomy in my lifetime and I am hoping for a good show as ...
- Mon Sep 30, 2013 10:45 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Mysterious Green Patches on the Sky (2013 Sep 30)
- Replies: 275
- Views: 523230
Re: APOD: Mysterious Green Patches on the Sky (2013 Sep 30)
It occurs early in the morning when the temperature is the lowest, so my suspicion is that water vapor is reaching the dew point. Not sure why it appears green but the look and flow of it is similar to clouds forming in the mountains.
- Fri Nov 16, 2012 10:37 pm
- Forum: The Observation Deck: Latest Sky Photography
- Topic: Recent Submissions: 2012 November
- Replies: 180
- Views: 128724
Re: Recent Submissions: 2012 November
Thank You for the email on anticrepuscular rays. Here are a few more images. We have seen these every evening for a week as the sun filters through towering cumulus clouds to our west here in Mae Taeng Thailand. http://teakdoor.com/Gallery/albums/userpics/33998/P1000913.jpg http://teakdoor.com/Galle...
- Wed Feb 09, 2011 11:46 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Rentry Physics
- Replies: 22
- Views: 82842
Re: Rentry Physics
Kinetic energy of a 1 kg glider at 7800 m/s orbital velocity = 30,420,000 Joules. Specific heat capacity of balsa = 2900 Joules/(kg.ºC) Temperature of reentering balsa glider ~10,500º C (= 30,420,000/2900). Art... Now we are getting somewhere! Agreed that the energy has to be dissipated before it c...
- Wed Feb 09, 2011 2:30 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Rentry Physics
- Replies: 22
- Views: 82842
Re: Rentry Physics
Forget about throwing something backwards.. That's not the question. It is tossed toward earth at a slow rate (make an assumption like 20 km per hour) from the space shuttle at its orbital velocity. Assume the glider weighs 1 kg on earth and has a wing span of 2 meters, wing chord of 20 cm, and a to...
- Tue Feb 08, 2011 9:47 pm
- Forum: The Library: Information Desk and Educational Resources
- Topic: Rentry Physics
- Replies: 22
- Views: 82842
Rentry Physics
A member of a Radio Controlled Aircraft flying forum (link below) asked an interesting question: If you throw a light balsa glider toward earth from the orbiting space shuttle, will it have enough energy to re-enter the atmosphere? If it does, will it burn up or safely glide to earth? Guesses are al...