Meteorology. a line drawn on a weather map or chart that connects points at which the barometric pressure is the same. Also, isobare [ahy-suh-bair] /ËaÉª sÉËbÉÉr/ (Show IPA). Physics, Chemistry. one of two or more atoms having equal atomic weights but different atomic numbers.
Hubble Essentials. With the Hubble Space Telescope on board, Discovery begins its roll maneuver after liftoff from Kennedy Space Center on April 24, 1990. This low-angle view of the launch shows the shuttle atop the external tank, flanked by two solid rocket boosters, as it rises into the sky.
NASA had started working on Hubble, the first telescope in the Great Observatories program, in 1977. It was originally supposed to be launched in 1985. But then the space shuttle Challenger exploded in 1986, and flights came to a halt while NASA tried to figure out how to safely resume them.