Jupiter

Jupiter

Interesting note…at least to me! The ancient Greeks did not know how big

Jupiter was…and Venus appeared brighter. So why did they name it after the most

powerful god?

When and where can you see it? Fourth brightest object in the sky (behind

the Sun, moon, and Venus).

Physical Properties Mass: 1.9 x 1027 kg or 318 Earth masses. Has more than twice the mass of all the

other planets combined. Still, it is only a 1000th the mass of the Sun. Its radius is 11.2 Earth radii. More than

1400 Earth’s would fit inside! It orbits 5.20 AU’s from the sun. Has no orbital tilt, therefore no seasons.

Rotation Rates Jupiter experiences differential rotation.

Because it is gaseous, not all parts orbit at the same rate!

Rate of rotation: 9 hours, 55 min Spinning this fast gives is an equatorial

bulge. Rate of revolution: 11.9 Earth years

Atmosphere Is dominated by atmospheric bands and the

Great Red Spot. The bands are areas of low pressure or

high pressure. The colors are based on complex chemical

reactions occurring in the bands. Some simple organic molecules (ethane)

have been detected in the clouds.

What is beneath the clouds? Well, more gases. This would be

considered to be the interior of the planet. Temperature and density increases with

depth. Eventually the gas becomes a liquid. Further down this liquid hydrogen becomes

metallic! Finally, there is a small extremely dense

solid core (may contain between 5-20 Earth masses.)

Weather on Jupiter The Great Red Spot averages twice the

diameter of Earth. Flashes resembling lightning have been

detected. White ovals depict storm systems. Brown ovals depict holes in the clouds that

allow for looks down into the lower atmosphere.

Reading on pg. 284 Almost a star?

Jupiter’s Magnetosphere Jupiter has a huge magnetosphere that

extends all the way out to Saturn! This results in aurorae.

Jupiter as a heat source Jupiter gives off more heat itself than it

receives from the sun. Why? Some is due to radioactive decay, just as in

the Earth. However, most is residual heat from its

formation.

Moons of Jupiter The current count is 63. The largest 16 are 10 km or bigger. The four largest, the Galilean satellites are

Io, Europa, Ganymede and Callisto, are named after the mythological attendants of Jupiter.

Some are locked in synchronous orbit with Jupiter, due to tidal forces.

Moons of Jupiter, cont. Some of the smaller moons orbit very

eccentrically. Some revolve in a retrograde direction. These smaller ones may have at one time

been part of a larger object that broke apart after being captured by Jupiter’s gravity.

Another interesting point (to me)! The orbital periods of the four Galilean

satellites are in the ratio of 1:2:4:8.

Io: Land of Volcanoes Very dense Geologically active - due to tidal forces from

Jupiter and the other Galilean satellites. More than 80 active volcanoes have been

discovered. The largest one is Loki – larger than the state of

Maryland and emits more energy than all of Earth’s volcanoes combined.

It’s mass and radius are similar to Earth’s moon.

Europa: Land of Ice Contains few craters. Is likely covered by an ocean that is frozen

over. This water could possibly harbor life

(marine).

Ganymede and Callisto: Twins?

Ganymede is the largest moon in the solar system (bigger than Pluto and Mercury).

Ganymede has maria. Ganymede used to have plate tectonics. Callisto is home to a large basin called Valhalla. Callisto shows no evidence of plate tectonics. It may have a layer of slush ice beneath its

surface.

Jupiter’s Ring Discovered by Voyager in 1979. Very small. Could be a result of meteoric impact on two

of Jupiter’s small moons.