Jumping Jupiter: The Marbled Planet

This beautiful photo of Jupiter‘s red spot and thick atmosphere was actually taken ten years ago by Voyager 1. Jupiter is an amazing planet, and so hard to conceptualize that I think, at times, we almost avoid explaining it in our science classes because it is so foreign. Here’s part of the NASA description, which does the marbled planet some justice (the highlights are my own):

“The most massive planet in our solar system, with four planet-sized moons and many smaller moons, Jupiter forms a kind of miniature solar system. Jupiter resembles a star in composition. In fact, if it had been about eighty times more massive, it would have become a star rather than a planet.

On January 7, 1610, using his primitive telescope, astronomer Galileo Galilei saw four small ‘stars’ near Jupiter. He had discovered Jupiter’s four largest moons, now called Io, Europa, Ganymede, and Callisto. Collectively, these four moons are known today as the Galilean satellites.

Galileo would be astonished at what we have learned about Jupiter and its moons in the past 30 years. Io is the most volcanically active body in our solar system. Ganymede is the largest planetary moon and is the only moon in the solar system known to have its own magnetic field. A liquid ocean may lie beneath the frozen crust of Europa. Icy oceans may also lie deep beneath the crusts of Callisto and Ganymede. In 2003 alone, astronomers discovered 23 new moons orbiting the giant planet, giving Jupiter a total moon count of 49 officially named — the most in the solar system. The numerous small outer moons may be asteroids captured by the giant planet’s gravity.

Jupiter’s appearance is a tapestry of beautiful colors and atmospheric features. Most visible clouds are composed of ammonia. Water exists deep below and can sometimes be seen through clear spots in the clouds. The planet’s ‘stripes’ are dark belts and light zones created by strong east-west winds in Jupiter’s upper atmosphere. Within these belts and zones are storm systems that have raged for years. The Great Red Spot, a giant spinning storm, has been observed for more than 300 years.

The composition of Jupiter’s atmosphere is similar to that of the Sun – mostly hydrogen and helium. Deep in the atmosphere, the pressure and temperature increase, compressing the hydrogen gas into a liquid. At depths about a third of the way down, the hydrogen becomes metallic and electrically conducting. In this metallic layer, Jupiter’s powerful magnetic field is generated by electrical currents driven by Jupiter’s fast rotation. At the center, the immense pressure may support a solid core of ice-rock about the size of Earth.”

More details and a full photo credit are here.