Only because it would be a dangerously short drop.
A typical altitude might be around 13,000 feet (4,000 meters), which gives the jumper about 60 seconds of free fall – the term used in skydiving to describe the moment the jumper exits the plane.
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Cleomedes was summarizing, of course, earlier work by Eratosthenes: Περὶ τῆς ἀναμετρήσεως τῆς γῆς (On the Measurement of the Earth). I know, that’s still later than Herodotus or even Aristotle, but Eratosthenes was at least contemporary to Archimedes, and while Cleomedes’ dates are wildly uncertain, he cannot have lived any earlier than the first century BCE (and might have lived as late as the third century CE).
Plato refers to a spherical earth in both the Phædo and the Timæus, and the idea was surely widespread in his time. There is weak evidence that he got the idea from Parmenides and Empedocles. He is known to have studied with the Pythagoreans.
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Exactly. And I’ve heard of these things called airplanes. The guy could have hired a Cessna for a couple hours and gotten much, much higher than 1875 feet, so he could see for himself. That’s why his schtick is obviously meant to fool the rubes and Trump supporters. But I repeat myself.
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Indeed, that’s part of what was so scary for me about this escapade.
Of course, having carried out the first part of the stunt (going up) , the second part was kind of inescapable.
I was disappointed to learn that the “steam powered rocket” wasn’t something out of Jules Verne; but it is an impressive risk anyway. After all, the system he used was pretty much what powered the Komet and blew up the Kursk.
That’s actually the basic root of an old Chelm joke (my poor updated rendering here): It’s night, and two people are sitting on a porch in Michigan, staring out at the Moon. One says to the other, “I wonder which is further away from us… the Moon, or Florida?”, to the which the other responds, “Silly! You can see the Moon.”
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Both of those used HTP, but they both used it as an oxidizer in more complex and hazardous fuel/oxidizer bipropellant engines.
The Kursk torpedos used kerosene as fuel, and the Komet used the highly toxic and dangerously unstable mixture the Germans called “C-Stoff” [Wikipedia].
HTP (aka “T-Stoff”) and C-Stoff are a hypergolic pair, which means they spontaneously ignite on contact with each other. This makes ground operations – tanking, detanking and cleaning – really hazardous.
BTW, a simple HTP monopropellant engine more similar to Mad Mike’s was used on the Bell Rocket Belt. Good choice there, too, since the (relatively) low-temp steam/oxy exhaust is less likely to scorch the pilot. (-:
But even by itself, HTP can be quite dangerous. It regards a wide range of organic substances as adequate catalysts, including minor grease or oil contaminants.
That can cause HTP tanks to explode quite violently and unexpectedly – so while it’s relatively safe to handle (esp. compared to other rocket propellants!), it still needs some pretty rigorous and thorough safety precautions.
And I’m with you on the parachute - I’d be waaayyy more worried about an untested 'chute rig working correctly at that low altitude than about the rocket itself.
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A bit of trivia I recently learnt about the Me-163: if you tried to land it while there was still any fuel in the tanks, the shock of the touchdown was enough to make the plane explode.
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I think’s he’s pretty much between Neptune and Pluto, full time
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We find our inspirations for homemade projects everywhere. I hope he had a grand day out.
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Also, I understand, inverted flight could lead to “fuel” leaking in to the cockpit and dissolving the pilot. How desperate must people have been to strap themselves in to those things.
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My Dad met him in the Fleet Air Arm. What a legend.
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Bonus Points for Wallace and Gromet reference !!
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Well, had he made it all the way to space, he would have killed himself.
Not from the lack of oxygen, I’m sure he would have brought a bottle, but …
… from space, it is impossible not to notice the Earth’s curvature.
So, the better he gets at this, the more he’s doomed.
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