Just like you don't believe that R.Kahane said that the "The Haredim are irrelevant!", not everything he ever said was written down chapter & verse; you'll just have to take it that he said it from those who were actually there.
That the Torah, Nach, Chazal all hold that the Earth is stationary, the evidence of the senses that it is stationary, all experiments that it's stationary, all practical sciences are performed on the basis of a stationary Earth (including NASA launches), and all savants admit that geocentrism cannot be disproved and as Einstein himself stated is at least
a primus inter pares: and you
dare to say that R.Kahane, R.MM Schneersohn, R.Kanievsky, R.Ginsburgh etc etc are wrong: you
kofer!
"We cannot feel our motion through space. Nor has any experiment ever proved that the Earth actually is in motion" (Lincoln Barnett, The Universe and Dr. Einstein, p. 73)