Glossary Jj


JOULE - Standard unit for energy. Another common energy unit is the calorie, which contains 4,184 joules. Dietary "calories" are actually kilocalories (103 calories) and are often written with a capital "C".

JOULE’S FIRST LAW -- Heat, Q, produced when a current, I, flows through a resistance, R, for a specified time, t, is:

JUPITER MASS - Mass of the planet Jupiter (2 x 1027 kg); equal to ~10-3 Msun.

JUPITER’S GREAT RED SPOT - Feature in the upper atmosphere of Jupiter ranging from ~25,000 to 40,000 kilometers in longest dimension (large enough to contain two to three Earths). The Red Spot, with wind speeds of 560 km/h, is produced by strong convection currents and has probably persisted for centuries. First definitely recognized in 1879, the Great Red Spot appears identical to the “Permanent Spot” recorded by Jean-Dominique Cassini in 1665, and may be related to a spot noted by British observer Robert Hooke in 1664. If so, the Great Red Spot has endured for at least 350 years.

Great Red Spot

Jupiter's Great Red Spot (top center). Image source: http://www.aerospaceweb.org/question/atmosphere/q0306.shtml.