The largest planet in our solar system, Jupiter, is still shrouded in mystery. The large planet, most notable for its large red spot, has captivated scientists for millennia. Since Galileo first documented it in 1610, we’ve learned a lot. But the King of the Planets is still revealing itself to us. Recently, astronomers at the University of Leicester discovered another large spot on the planet. They’re calling it the ‘Great Cold Spot’.
So, what do we know about Jupiter’s atmosphere, and what does this new spot bring to the table?
Jupiter’s Bands and Spots
We know Jupiter is the biggest planet, and it has that red spot. But what else do we know about this massive planet’s atmosphere?
First and foremost, the most important thing to remember about Jupiter is that it is a gas giant. The planet doesn’t have a true rock surface. No mountains or valleys or plains, though it is suspected to have a liquid hydrogen ocean. There is nothing stopping or slowing the wind speeds inside the atmosphere.
Jupiter’s distinctive bands that wrap around the planet are created by warm gases rising from the planet’s surface up into the outer atmosphere. And Jupiter’s rotation creates the swirls and intricate patterns inside those bands.
The massive planet has a day every 10 hours. That kind of spinning creates immense wind speeds in the atmosphere, which separate and distinguish Jupiter’s bands.
The Great Red Spot is a storm in Jupiter’s southern hemisphere that has been going on for almost three hundred years. Can you imagine that? You’d wonder what the sun looked like. The storm is older than the United States.
Because there are no land features, there is nothing to slow the storms down. So the Great Red Spot could continue to last for another hundred or so years. Recently, a few of the smaller spots joined together to create a spot about half the size of their more famous brother.
The Great Cold Spot
So, what is this new spot, and what is causing it?
To begin with, the newest spot doesn’t have the same distinct coloration as it’s Great Red cousin. They appear as a localized dark spot near the northern pole of the planet. Almost like a large shadow being cast on the planet, only, there is nothing to cast the shadow.
Temperature readings show that the spot is around 200 degrees Kelvin (99.67℉) cooler than the surrounding atmosphere which is usually around 700-1000 K (800-1340℉). Additionally, unlike its cousin, the spot appears to be much more sporadic in showing up. Changing the size and shape multiple times over the fifteen-year span of the observation.
So, what is causing it? Well, that is a good question. The researchers believe that Jupiter’s aurora is causing the region of cooling by affecting the planet’s magnetic field. Unlike Earth’s aurora, which is caused by radiation from the sun, Jupiter’s aurora is caused by volcanic gases from the nearby moon Io and radiation from the sun. These gases are much more consistent that radiation bursts from the sun. This leads to Jupiter having much more pronounced auroras.
If the aurora is causing the cool spot, it could potentially explain why the spot changes shape and size as often as it does. Research by Tom Stallard of the University of Leicester indicates that the aurora is heating the planet’s atmosphere. His speculation is that this heating effect is causing a cool spot in the layer between the warm atmosphere and space.
Since the aurora’s intensity changes based on the volcanic activity on Io and the sun, it makes sense that this heating effect would change, and the size of the spot would change as a result. Similar to how changing the shape and size of a bowl will cause any liquid inside it to change shape and size as well.
It is certain that we will have to explore and observe this spot more to find out exactly what is going on. With the Juno orbiter around Jupiter, maybe we’ll get some of the answers we’re looking for. We won’t be able to go explore it anytime soon since Jupiter’s atmosphere tends to melt or dissolve any probe we build. So, it looks like we’re going to have to wait to see what comes of this, and what it means for the gas giant.
Featured image credit: NASA, ESA, and J. Nichols (University of Leicester)