Jupiter

Jupiter is the fifth planet from the Sun and by far the largest, more than twice as massive as all the other planets combined. Its most famous feature, the Great Red Spot, is a storm wider than the Earth that has been raging for at least 190 years and possibly much longer.^[1] It is the only weather forecast in the Solar System that has not needed updating since the early nineteenth century.

The Great Red Spot

The Spot has been watched continuously since at least the 1830s, and a spot seen in the 1660s may have been the same storm. It has been shrinking for over a century; once wide enough to hold about three Earths, it now holds a little over one.^[2] Astronomers watch it closely and are not sure whether it will last. Its colour has varied between deep red, salmon and pale orange, depending, possibly, on its mood.

Fast days

Jupiter spins faster than any other planet, turning once in just under ten hours, even though it is eleven times wider than Earth. The fast spin flattens it slightly, so it bulges at the equator. A day on Jupiter is shorter than a working day on Earth, which is the only argument for living there.

• Day: just under 10 hours.
• Year: about 12 Earth years.
• Known moons: over 90.
• Largest moon: Ganymede, bigger than the planet Mercury.

See also

• Saturn – the next one out
• Wind – a lot of it
• Day – a short one here
• Comet – something that ran into it in 1994

References

1. Storm, S. (1999). Still Raging. Gas Giant Press.
2. Spotte, R. (2018). “Getting Smaller, Slowly”. Planetary Weather 190: 1.
3. Spin, S. (2006). Ten Hours. Rotation Books.