What does it serve to know that [quasars] are converting matter to energy at a rate that equates to the complete annihilation of a planet the size of the Earth ten times a second? Or that all the fires of the sun, from its birth to its death, would be a few weeks’ worth of work to one of them [1]

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The current International Celestial Reference Frame uses 3000 quasars to define the axes against which all [GPS] measurements – of the Earth’s position, of satellites, and of everything else – are made. Thanks to quasars, these axes are specified with a precision of ten microarcseconds. That is the angle between a line connecting your eye to a point on the surface of the Moon and a second line connecting it to a point two centimetres to the right of the first. [1]