Space Weather

Why Earth’s rotation makes Jupiter’s Red Spot impossible here.

Did you actually think Sandy, Andrew even Katrina were bad? These hurricanes that caused widespread destruction to the U.S. are mere child’s play compared to some storms outside the Earth’s atmosphere. If you were sitting at home on your couch and your local meteorologist began to rant about the latest storm that will bring 400 mph winds and temperatures plunging below -250°F, you would surely think he is lying. Now imagine those conditions lasting for at least 400 years and counting. Well, although this sounds like the makings of a science-fiction movie, this storm does exist as the Great Red Spot on Jupiter.

All major storms on Earth usually have a large center of low atmospheric pressure with cyclonic motion (counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere). These cyclones dominate the Earth’s weather patterns and can cause significant destruction at the same time. However, interestingly, the Great Red spot in Jupiter’s Southern Hemisphere is actually associated with anti-cyclonic (high pressure) flow.

Although there are countless differences between the Great Red Spot on Jupiter and Earth storms, there are also some surprisingly striking similarities. All storms on Earth circulate due to Earth’s rotation.  This rotation deflects the direction of a moving object – a force known as the Coriolis. This deflection allows cyclones to rotate, giving them the ability to strengthen into powerful storms. Since all planets in our solar system rotate, the Coriolis effect is also present, ranging in strength due to size and rotational frequency of the planet. Since Jupiter is the biggest planet in the solar system and makes a complete rotation in only~10 hours, the Coriolis force has an exceptionally strong effect on the planet. This fast rotation is directly related to the strengthening of a storm and wind speeds resulting in a Great Red Spot that has winds up to 400 mph.

The strongest surface wind gust ever recorded on Earth was 253 mph during Cyclone Olivia in the late 90s. Winds at this strength have the ability to demolish almost all buildings in their path. By adding another 150 mph of sustained winds on top of this gust, there most likely would be no evidence that a structure ever existed. But before we put a category 20 hurricane on Earth, it is even possible for conditions like these to be on our planet?

Since, Jupiter rotates two and a half times faster than Earth, causing the stronger Coriolis force and winds, a storm like the Great Red Spot could not exist on Earth.  Thus, you don’t need to worry about a 400 mph storm busting down your door.  Just don’t let the people at the Weather Channel know how strong storms can get on Jupiter or they may have to come up with a whole new list of “storm” names.