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Sorry, I must not have been clear. Sullivan's book outlined how the fox's tail had became invisible due to the precession of the equinoxes on the morning of winter solstice in 650 AD. The pic I uploaded shows the sky with a sun depression of 20° (I believe) at that time. The 'fox' was a Milky Way 'object,' as it wasn't a constellation in those terms (if memory serves me correctly). The Milky Way disappears from the sky slightly before astronomic dawn, so the Milky Way would have started disappearing shortly after that 20° depression, if not at that 20° depression.
Benfer, in his article, was arguing that the Milky Way and the 'fox's tail' was clearly visible in the sky, because he didn't take twilight into account. In other words, he was saying that the sky instantly goes from dark enough to see the stars, to instantly light once the sun breaches the horizon. Therefore the 'fox' could be seen all the way up to sunrise. Which is utter nonsense.
Does it make sense that way?
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David O'Neil wrote: Does it make sense that way? Yes, I fully understood your position on the subject. Not sure if I want to get involved in your academic debate with that guy.
I would be willing to play the straw man with you:
Straw Man wrote: Is the altitude at sealevel in your astronomy software? The Andes are at nearly 7000m at the peak. A quick calculation tells me that you would be able to see approximately 300km over the horizon from the Andean mountain peaks at that elevation.
Not my argument, just trying to generate a position for you to defend.
Best Wishes,
-David Delaune
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The only way to find out is to go there and see for ourselves when the Milky Way disappears before sunrise. Or have a very, very good model of atmospheric absorption vs temp at that time of year, yada, yada, yada. Even at 7000m, I know it won't be visible ten minutes before sunrise, which is what he was saying. Go to street view. Here is Machu Picchu: Google Maps. The horizon is just more mountains.
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David O'Neil wrote: The only way to find out is to go there and see for ourselves Looks like Dr. Bromberg from the University of Toronto has a neat little tool that will calculate civil, nautical, and astronomical twilight values for arbitrary dates.
The Kalendis Calendar Calculator[^]
Plug in your dates/coordinates and let's have a look at the values.
Best Wishes,
-David Delaune
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I wrote a script for Stellarium to do that. You can view (an old version of?) it here: Stellarium Scripting. The picture I posted is at 20° sun depression I believe, which is 2° greater than astronomic dawn. If you want my most recent version (which may be exactly the same as that - I haven't looked at it in a while), I'll post it.
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What did he say when you asked him:
Why is the sky blue?
And the sunset red?
Same answer:
Rayleigh’s scattering which is determined by the atomic radius of the atmospheric gases.
I did have to go to college to learn that.😊
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Bingo.
If you think 'goto' is evil, try writing an Assembly program without JMP.
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Ultimately, I would say: Yes, it will take off.
What does the plane care what happens to the wheels? The thrust is there no matter how fast (and which direction...) the wheels are turning.
The reason why seaplanes can also take off without wheels
modified 10-Apr-22 10:17am.
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It has nothing to do with either wheels or floats. It can only take off if it is moving forwards at take off speed, relative to the ground. If it is stationary relative to the ground then there will be no lift applied to it.
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Lol think again about it
If you are right a rocket can go only if it has wheels
Sorry, but the thrust of the jets really has nothing to do with the wheels.
And it will moving forward because of the thrust. Easy physics
[Edit]
It would be another thing in case the wheels are glued on a conveyor belt
modified 10-Apr-22 11:45am.
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0x01AA wrote: If you are right a rocket can go only if it has wheels That has nothing to do with the question. Rockets travel in a vertical direction relative to the ground.
0x01AA wrote: the thrust of the jets really has nothing to do with the wheels. I never said it did.
0x01AA wrote: And it will moving forward because of the thrust. not if the conveyor belt is counteracting that thrust.
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Quote: not if the conveyor belt is counteracting that thrust. Now I come to agree ... but that was never mentioned to be like this
[Edit]
No it doesn't really matters, it is constructed. Otherwhise you need to explain how 'not if the conveyor belt is counteracting that thrust' can be done in praxis
And that would be then only a very consrtucted thing, which has nothing to do with praxis
modified 10-Apr-22 12:13pm.
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Sorry holy sh*t what?
Quote: That has nothing to do with the question. Rockets travel in a vertical direction relative to the ground.
What? Rockets work only vertical?
Only nonsense. Stop doing this...
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What on earth are you talking about?
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Read the nonsense you wrote
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Sorry, I'm tired of reading the nonsense you wrote.
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Did'nt you write this?
Quote: That has nothing to do with the question. Rockets travel in a vertical direction relative to the ground.
?? So rockets are only able to fly vertical??
Read this: Reaction engine - Wikipedia[^]
modified 10-Apr-22 15:17pm.
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Quote: Sorry, I'm tired of reading the nonsense you wrote.
Stiff upper lips: I'm never wrong...
I'm tired to reading your nonsense and I'm wondering why CP let your nonsense trough
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Enough, guys.
cheers
Chris Maunder
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Quote: It has nothing to do with either wheels or floats. It can only take off if it is moving forwards at take off speed, relative to the ground. If it is stationary relative to the ground then there will be no lift applied to it.
Sorry again. If you don't see from what an airplane is driven (and not glued by wheels to the ground especally not to the jets) then I can't help.
It is simply physics and there is no need to construct unreal cases.
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I have not constructed an unreal case, merely stated the truth.
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Action - reaction. The wheels won't turn - the conveyor will move with the plane; the forward movement of the wheels moves the conveyor.
Nothing is being applied to the wheels; it's only holding the plane up. Along the lines of spaceship thrusters: no friction needed.
I think you can assume the conveyor acts as a friction-less surface.
"Before entering on an understanding, I have meditated for a long time, and have foreseen what might happen. It is not genius which reveals to me suddenly, secretly, what I have to say or to do in a circumstance unexpected by other people; it is reflection, it is meditation." - Napoleon I
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Many years ago at a tiny company where we consumed our lunches together at the conference table we had a similar heated discussion this time re/ if you walked up a down escalator w/o changing your elevation did you do any work? I now can not imagine why this was so perplexing at the time. Then there is Richard Feynman wondering if one can piss whilst upside down.
Below is my "Signature" apologies if offends
My sympathies to the SPAM moderator
"I once put instant coffee into the microwave and went back in time." - Steven Wright
"Shut up and calculate" - apparently N. David Mermin possibly Richard Feynman
“I want to sing, I want to cry, I want to laugh. Everything together. And jump and dance. The day has arrived — yippee!” - Desmond Tutu
“When the green flag drops the bullshit stops!”
"It is cheaper to save the world than it is to ruin it."
"I must have had lessons" - Reverend Jim Ignatowski / Christopher Lloyd
"Dripping water hollows out stone, not through force, but through persistence." - Ovid, Roman poet
Personal Web Page https://mypaltrythoughts.blogspot.com/[^]
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Thanks everyone for your replies, the links and the videos.
When I posted this question, little did I imagine that it would raise such an intense discussion. Thanks once again.
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