Tilt of Jupiter

Jupiter, like Earth, has an axial tilt. A planet’s axial tilt is the angle between its rotational axis and a line perpendicular to its orbital plane. The tilt of Jupiter is 3.13 degrees, significantly less than Earth’s. The combination of a small axial tilt and the hyper-speed that Jupiter rotates at(one rotation every 10 hours), mean that the planet does not have seasons.

Jupiter’s small axial tilt causes the poles to receive less energy from the Sun. Since the planet never tilts enough to balance temperatures, the poles draw heat from the planet’s core. The convection from the interior of the planet may also explain why winds on Jupiter reach in excess of 540 kph. Studies done by Jonathan Aurnou, UCLA assistant professor of planetary physics and his team have suggested that the combination of the correct geometry, turbulent convection, and rapid rotation explain the devilishly quick winds. The winds on Jupiter do not slow like they do on Earth. Most of the winds have maintained the same speed for the entire 300 years that astronomers have been documenting their observations of Jupiter.

The furious winds, differing temperatures, and convection also explain why storms on Jupiter can appear, then build to massive proportions within a few hours. A recent storm grew to be over 2,000 km in diameter within 24 hours. Jupiter’s Great Red Spot is a single high altitude storm that has been raging for at least 500 years. The first scientist to record its existence was Giovanni Cassini in the 1600s. At one time the storm was over 40,000 km in diameter. It has been known to wax and wane, but never disappear.

Earth’s axial tilt is 23.5 degrees. This tilting is one of the factors that creates the seasonal changes on our planet. It also allows the Sun’s energy to heat the majority of the planet’s surface at different times of the year. The Earth’s axial tilt changes slowly over time and varies between 22.1 to 24.5 degrees. The seasons are in reverse when the planet is at each extreme.

The small, 3.13 degree tilt of Jupiter helps to explain the furious winds and why storms in the Jovian atmosphere never seem to go away, but it is only one of thousands of facts to be had about the planet. Hopefully, it is the one fact that encourages you to explore even more.

Here’s an article from Universe Today describing how convection inside Jupiter is the source of its winds, and another discussing how giant storms on Jupiter can appear in a single day.

Here’s an article from Wikipedia describing axial tilt in general, and more information on Hubblesite’s News Releases about Jupiter.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Source:
NASA