I gave Bret the same feedback. My point was that if he could package up a smaller version of it (say with a pico projector and a simple webcam) then you could have a ton of creative efforts happen in parallel. There are a ton of use cases for the home and for schools and I'm sad that the potential there is not fully realized..
Create in English, Krit in Sanskrit, ecrit in French.
Death is Mrit in Sanskrit, and morte in French.
Is is astu in Sanskrit, Ast in Farsi (if I recall correctly).
It's there, just at the VERY bottom as I deemed it more of a site of examples than a site to make shaders directly. I think you're right though that maybe that was a bad call.
And sometimes the legacy is just that the world is a better place thanks to their efforts, and has not much to do with having your name all over the place.
Even without the weight of the first stage, I'd imagine this would have to be a massive quantity of balloons. Lifting an adult human takes a house-sized amount of balloons. Fun to imagine dragging a stadium sized quantity of hydrogen balloons a mile up before detonating them with the engines, but likely impractical. Perhaps rockets could be launched from the top of a giant zeppelin once it reaches altitude? (~4 orders of magnitude larger than the Hindenberg)?
I've always been curious as to how effective a hydraulic lift could be at reducing necessary launch weight. A disproportionate amount of fuel is used at the beginning of the first stage when it is the heaviest, so seems like the benefit would be quadratic - Saturn V took 12 seconds to clear the tower. Would require major infrastructure, but if you could "throw" the rocket so it starts at a greater initial speed, seems like you could bend the rocket equation favorably. Perhaps even a giant underground potato-canon or railgun.
> I've always been curious as to how effective a hydraulic lift could be at reducing necessary launch weight.
I suppose you'd be able to approximate the effect by comparing the delta v needed to launch from a sea-level site (Cape Canaveral, Kourou, etc.) with that needed to launch from one of China's inland sites (e.g., Taiyuan, which sits at 1500m). I have no idea whether this data is publically available, though. I'd guess the bulk of your performance improvements would come from increased engine performance due to the lower ambient pressure (~0.83 atm according to Wolfram Alpha) rather than the increased altitude, since most of the energy is needed for horizontal acceleration [0]. The increased thrust would mean lower gravity losses, but I wouldn't be able to say how much.
A space plane is going to be more efficient. The idea is you fly the aircraft with jet engines (which use oxygen in the air) to their maximum altitude, and then switch over to rocket engines (which use oxygen in the fuel).
So far all demonstrations have been of rockets mounted under a jet engine powered aircraft, which then detaches at space launch. But I don't think there is any reason why you couldn't have a SSTO air/spacecraft, other than we don't have the propulsion technology yet - it works in KSP though :-)
What is so special about the speed of light? As a thought experiment, if everyone on the planet was blind, would c have been replaced by the speed of sound?
The first very special thing that was observed about the speed of light is that it is NOT relative. That is, if I fire Alice light beam at you from a moving train, while Bob fires a beam at you from a platform, both beams will reach you at the same time. Sound does not behave the same way, light was the first thing that we observed like this.
This was a gigantic problem, an experiment contradicting one of the most fundamental laws of nature as we knew them at the time - Galileo Galilei's principle of relativity.
Note that this observation has nothing to do with our eyes's ability to perceive light. The same observation will not happen with sound waves; and it will hold even for frequencies of light that we can't directly observe with our bodies, such as radio waves.
As others note, it was later discovered that this is not a special property of light itself. It is in fact a special property of the universe, and it applies to any particle without mass; the photon happens to be the only massless particle that we can directly observe, so it was the one which gave the name to the physical quantity.
> That is, if I fire Alice light beam at you from a moving train, while Bob fires a beam at you from a platform, both beams will reach you at the same time.
That's wrong. Simultaneity is ill-defined in relativity.
The correct example is, "if Alice fires a light beam at you from a moving train and Bob fires a light beam from you from the platform, you will measure the Alice photons as going equally fast as the Bob photons.
I recently learned this and it blew my mind because it had never occurred to me.
Another way to put it is that when you’re in a moving bus and you throw a ball towards the front of the bus, the ball is moving the speed you threw it plus the speed of the bus, but, when you shine a light, the photons from the light are moving the same speed as someone off the bus! That seems super weird.
Exactly. Now build a clock by bouncing the light between two mirrors, and think about how the clock looks like in the bus, and outside of the bus. -> special relativity.
As chilinot said, it’s the speed of any massless particle in a vacuum. A massless particle has nothing slowing it down, so it moves at the maximum possible speed. It’s actually the propagation speed of cause and effect, or put another way, how long it takes for a quantum event to affect whatever is in the adjacent point one Planck length away. It’s simply how quickly these things ripple forward when there is nothing slowing these ripples down.
Every other massless particle moves at the same speed. “Sound” is not a massless particle, it’s propagation of the compression of matter, so therefore moves much, much slower and would not replace c. It has nothing to do with what we can observe and rather to do with its properties. Personally, I find referring it to as “the speed of light” is confusing since it rarely has anything to do with light/photons other than that light happens to move at that speed.
I watched this recently[1] and the whole relativity thing made me think that its kinda like how in games often physics is processed as local clusters (for parallelism) and it made me think that reality appears to be simulated in this local clusters too. Relativity exists because that way each local cluster is independent and can be simulated in parallel, sharded across the servers! :)
Hell, why not take it a step further and say that the simulation is relative to an observer (which can be an inanimate thing, of course) as an optimisation because why bother simulating what isn’t seen or interacted with by an observer?
It is the speed of cause and effect.
If something changes at location X, that cannot cause anything to change at location Y faster than the distance between X and Y divided by the speed of light.
Light (in a vacuum) goes as fast as the speed of cause and effect. And it just so happens that the speed of light is pretty easy to measure (as compared to other possible things).
So if we were all blind, we would still be affected by this speed.
The speed of light is just the speed of any particle without matter. We just use "speed of light" since its simpler to understand and talk about rather than saying "speed of matter-less particles".
The speed of sound is the speed of air-molecules bouncing into each other (~300m/s). Since air-molecules have matter, they dont travel at the speed of light.
The difference between sound and light is that sound needs a medium. This medium breaks the symmetry: There is a special system, the one in which the bulk of the medium doesn't move.
For light, you don't have that. All reference systems are equal, independent of the speed they move with respect to each other. Light appears at the same speed in all of them. That's not possible with Newtonian velocity addition.
The experimental "proof" of the frame-independence comes from the michelson morley experiment. (Scare-quotes, because you can't prove things in physics, only disprove)
Even for the app - if its a cost argument, then allow others to compete on a cost basis. Of course, apple will not let you set up your own app store with the same guarantees that apple provides around privacy security etc. If its a discovery and cost of marketing argument than I dont understand the perpetuity of payments, you can pay a first time purchase fee but subscriptions afterwards should not have any fees tacked on.
