"... in the late 1940s, as the new technique of radio astronomy was developed, a brand new window was opened on the universe. Through this window the outer world looked strangely different. Copious amounts of power were emitted by streams of charged particles moving with nearly the velocity of light in vast magnetized clouds in the deep recesses of space. Additional windows are now available. The infrared, the domain of heat radiation where we could see but darkly, is intensively being explored — thanks to great technological advances. Observations with satellites flown above the earth's atmosphere have wonderfully expanded our horizons. The International Ultraviolet Explorer, IRAS, and Einstein are but three examples of instruments that have revolutionized our understanding the ultraviolet, the infrared, and the X-ray regions. Ground-based radio observations, together with X-ray and gamma-ray detectors flown in satellites, have established the active field of high-energy astrophysics. The mysterious cosmic rays, long a province worked by a small band of devoted physicists, were shown to be an integral part of the expanding scene. Radio galaxies and quasars revealed powerhouses of unbelievably high wattage radiating in remote space, while pulsars made sense only in terms of incredibly dense cores of defunct stars, where the very nuclei of the atoms, themselves, were simply squeezed beyond redemption. In some instances, matter was even further crushed into black holes from which nothing, neither particle nor radiation, can ever escape."