"Neil deGrasse Tyson, perhaps the most famous astrophysicist in the world and a seemingly affable guy, upset teachers and started something of a Twitter frenzy with a tweet blaming U.S. schools for people who believe the world is flat."
https://www.washingtonpost.com/news/answer-sheet/wp/2017/07/21/neil-degrasse-tyson-blames-u-s-schools-for-flat-earthers-and-teachers-arent-amused/
Teachers are innocent. The blame should be put on Neil deGrasse Tyson himself and brothers Einsteinians who, for more than a century, have been destroying human rationality by teaching idiocies like this one:
Neil deGrasse Tyson, Death by Black Hole: And Other Cosmic Quandaries, pp. 123-124: "If everyone, everywhere and at all times, is to measure the same speed for the beam from your imaginary spacecraft, a number of things have to happen. First of all, as the speed of your spacecraft increases, the length of everything - you, your measuring devices, your spacecraft - shortens in the direction of motion, as seen by everyone else. Furthermore, your own time slows down exactly enough so that when you haul out your newly shortened yardstick, you are guaranteed to be duped into measuring the same old constant value for the speed of light. What we have here is A COSMIC CONSPIRACY OF THE HIGHEST ORDER."
https://www.amazon.com/Death-Black-Hole-Cosmic-Quandaries/dp/039335038X
If we have to choose between the flat-earth idea and the idea of "a cosmic conspiracy of the highest order", I think the former is less detrimental to sanity. So some day flat-Earthers will naturally come to power in science, as people less insane than Einsteinians.
The speed of light is variable, not constant, and this is obvious. Consider the following setup:
A light source emits a series of pulses equally distanced from one another. A stationary observer (receiver) measures the speed of the pulses to be c and the frequency to be f=c/d, where d is the distance between the pulses:
http://www.einstein-online.info/images/spotlights/doppler/doppler_static.gif
The observer starts moving with constant speed v (v << c) towards the light source - the frequency he measures shifts from f=c/d to f'=(c+v)/d:
http://www.einstein-online.info/images/spotlights/doppler/doppler_detector_blue.gif
The following formula is correct:
f' = c'/d
where c' is the speed of the pulses as measured by the moving observer. Clearly,
c' = c + v.
That is, the speed of the pulses varies with the speed of the observer, in violation of Einstein's relativity. Any correct interpretation of the Doppler effect unavoidably leads to the same conclusion:
http://www.einstein-online.info/spotlights/doppler
Albert Einstein Institute: "In this particular animation
http://www.einstein-online.info/images/spotlights/doppler/doppler_detector_blue.gif
which has the receiver moving towards the source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." [end of quotation]
Since "four pulses are received in the time it takes the source to emit three pulses", the speed of the pulses relative to the receiver (observer) is greater than their speed relative to the source, in violation of Einstein's relativity.
Pentcho Valev