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Planetary Ponderings - Part 5 of 9: Jupiter

by Perry Pezzolanella, MVAS

Huge is an understatement when describing Jupiter. Everything about this giant planet is on a scale that would dwarf the Earth. There is much to ponder when it comes to the King of Planets.

  • Jupiter is the fifth planet from the Sun with an average distance of 483 million miles. It can get as close as 459 million miles or as far as 506 million miles from the Sun.
  • Jupiter is the largest planet with an equatorial diameter of 88,164 miles and has the most moons in the Solar System with 62.
  • A day on Jupiter is the shortest of all the planets lasting only 9 hours and 50 minutes, but a year lasts 11.86 Earth years.
  • Jupiter's rapid rotation actually flattens the planet at the poles so that its polar diameter is 83,519 miles, or about 4500 miles less than at the equator.
  • Jupiter can come within 365 million miles of Earth, appear as large as 50 arc-seconds across, and blaze as bright as magnitude -2.9.
  • Because Jupiter orbits farther from the Sun than Earth, it can never appear less than 99% lit.
  • Jupiter is so massive that it can hold over 1200 Earths or it can hold all of the other planets with room to spare.
  • Jupiter is nothing more than a ball of gas surrounding a small rocky core. The atmosphere is thousands of miles deep and is 86% hydrogen, 14% helium, and less than 1% of all other trace elements.
  • Jupiter is completely cloudy and the riot of color in the clouds is due to sulfur, methane, phosphine, and other compounds. Winds exceeding 300 miles per hour help create the belts and shears.
  • The dark belts are areas of clear, dry, sinking air. Light zones are areas of cloudy, moist, rising air.
  • The spots are huge thunderstorms and hurricanes with the Great Red Spot the mightiest of all. The lightning is capable of vaporizing a city.
  • The Great Red Spot can easily hold two Earths and its reddish color is due to phosphine. It has the highest and coldest clouds on Jupiter at -240 F.
  • There is no solid surface on Jupiter. The atmosphere thickens into slush with increasing depth, pressure, and heat. This eventually merges into a bizarre state of metallic hydrogen.
  • Jupiter is not a star that failed. It is 100 times less massive than what is required to become a star. There is no way it will ever become a star.
  • Jupiter's molten iron core and metallic hydrogen mantle creates the most deadly radiation belt in the Solar System; it can kill a person instantly and disable a spacecraft nearly as quickly.
  • Jupiter has a thin, dust ring that reaches almost down to the cloud tops.
  • Jupiter has four moons that are worthy of being planets: Io, Europa, Ganymede, and Callisto.
  • Callisto is almost as large as Mercury with a diameter of 3000 miles and is composed of rock and water ice.
  • Callisto is covered with so many craters that new ones can only form by destroying old ones.
  • Ganymede is the largest moon in the Solar System and larger than Mercury with a diameter of 3267 miles. It is composed of rock and water ice and has polar ice caps and craters.
  • Ganymede has extensive faulting and wrinkling, is enshrouded in a thin oxygen atmosphere, and has a weak magnetic field.
  • Europa is 1,950 miles in diameter and the flattest world known. The difference between the deepest pit and highest hill is barely 600 feet.
  • Tidal forces from Jupiter have flexed Europa enough to create a global ocean beneath the thin crust of water ice.
  • Io is 2250 miles in diameter and the most volcanically active world in the Solar System with dozens of active volcanoes.
  • A few volcanoes have plumes towering 250-300 miles into the sky and lava as hot as 3,000 F. Most of the volcanoes spew molten sulfur.
  • The pizza coloration of Io is due to sulfur from the volcanoes at different states of liquid and solid dependent upon the temperature.
  • Tidal flexing from Jupiter has made Io so volcanically active that it has literally turned itself inside out several times during its lifetime.
  • Galileo was the first spacecraft to orbit an outer planet and the first to drop a probe into the atmosphere of an outer planet.

Two planned missions have already been cancelled, but eventually there will be many new and exciting missions to Jupiter and its moons where pondering the impossible is possible and where extremes are the norm.