And the rotation has to be both continuous and at a constant speed, which for the LZT is 8.5 revolutions per minute.

FORBES: Liquid Mirror Telescope Technology Finally Going Mainstream

And in the science of optics, the fact that the speed of light is constant in a vacuum is taken for granted.

FORBES: Why Marco Rubio Needs To Know That The Earth Is Billions Of Years Old

Because it is far more efficient to unwind the spring at a constant speed, rather than stopping and starting it, this provides enough energy to run the radio for an hour.

ECONOMIST: MONITOR