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BRIGHT LIGHT OVERHEAD
- Thread starter pred
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Thanks for that, but it was on the 31st May I saw it.
But I'll know when to look next time.
Muchass Grassiass as PonchoPedro will be saying.
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Probably the photo of the one I saw tied in a knot.
Maybe the Guiness Book has a category for this. . .?
No they don't. The ISS has an apogee of 417km. This is not outside the atmosphere.
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The twain shall meet !
http://www.fai.org/icare-records/100km-altitude-boundary-for-astronautics
... In Aeronautics, level flying higher and higher meant to deal with less and less dense atmosphere, thus to the need of greater and greater speeds to have the flying machine controllable by aerodynamic forces. A speed so big in fact, that, above a certain altitude, could be close or even bigger than the circular orbital speed at that altitude (i.e. lift was no longer needed, since centrifugal force took over; and consequently aerodynamic flight was meaningless). Conversely, in Astronautics, lower and lower orbital flying led to encounter more and more dense atmosphere, so much that it would be impossible to keep the orbit for a number of turns around Earth without a significant forward thrust (thus making the free fall, or orbiting, concept meaningless).
A lot of calculations were made, and finally it was reached the conclusion, accepted by all scientist involved, that around an altitude of 100 Km. the boundary could be set....
The 100-Km altitude, ever since named the “Karman Line”, came thus into existence as the boundary separating Aeronautics and Astronautics....
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http://www.fai.org/icare-records/100km-altitude-boundary-for-astronautics
... In Aeronautics, level flying higher and higher meant to deal with less and less dense atmosphere, thus to the need of greater and greater speeds to have the flying machine controllable by aerodynamic forces. A speed so big in fact, that, above a certain altitude, could be close or even bigger than the circular orbital speed at that altitude (i.e. lift was no longer needed, since centrifugal force took over; and consequently aerodynamic flight was meaningless). Conversely, in Astronautics, lower and lower orbital flying led to encounter more and more dense atmosphere, so much that it would be impossible to keep the orbit for a number of turns around Earth without a significant forward thrust (thus making the free fall, or orbiting, concept meaningless).
A lot of calculations were made, and finally it was reached the conclusion, accepted by all scientist involved, that around an altitude of 100 Km. the boundary could be set....
The 100-Km altitude, ever since named the “Karman Line”, came thus into existence as the boundary separating Aeronautics and Astronautics....
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Nothing to do with shadows. The average duration is about 6 min 30 seconds when directly overhead. Athough in practice it rarely does actually pass directly overhead. This site is great for tracking. Click on the time you are interested in and it shows you a map of the pass.
http://iss.astroviewer.net/observation.php
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"Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). "
A WAG is that this ISS sucka' is going at over Mach 20.
Yes, but that does not mean that 417km is outside the atmosphere.
You don't know what the definition of Mach is, do you?
Jist seen it from Scotland too, Probably not as bright as you saw it though Pred, but it was clearly visible in the night sky looking South.
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