Frequently Asked Questions

Jupiter's atmosphere

Why study atmospheres of other planets?

The equations that govern the dynamics of Earth's atmosphere are the same on other planets. Jupiter, for example, is nearly 10 times larger in radius and rotates more than twice as fast. Therefore, it is the perfect laboratory to study aspects of fluid dynamics at huge scales that are not possible on Earth. This gives us valuable insight into the physics of atmospheric dynamics. Furthermore, the outer planets hold the key to understanding how our Solar System formed, since their composition is much closer to the original composition of the gas that formed the Solar System. Therefore, understanding the atmosphere of these planets provides valuable insight into the Solar System's formation history.

What is Jupiter's atmosphere made of?

Jupiter contains an atmosphere that is primarily hydrogen and helium (about 87% hydrogen and about 13% helium). The remaining fraction is composed of heavier components such as ammonia, methane, water, phosphine, hydrogen sulfide etc. The exact quantities of each of these heavy elements is a question of much research.

What are Jupiter's clouds made of?

Jupiter contains three main cloud layers (see the second figure in the research page for an illustration) that is composed of ammonia, ammonium hydrosulfide and water.

Where do the different cloud colors come from?

Ammonia clouds form the bulk of the bright white clouds that we see in images of the jovian atmosphere. There is still a lot of debate on the exact chemical nature of the reddish/orange jovian clouds (called the 'chromophore'), but one theory is that it is a single chemical that forms a hazy layer above the clouds that changes color when struck with UV radiation from the Sun (a process known as 'photochemistry'). This is known as the "Creme Brulee" model since this coloring agent is much like dusting that sits on the surface layer of the dessert.

How can you tell if a cloud is made of water, ammonia, or ammonium hydrosulfide?

It is difficult to determine the exact composition of a cloud, but the current theory suggests that the bright white clouds in Jupiter's atmosphere are pure ammonia, while the deep red/brown clouds have some amount of ammonium hydrosulfide or a different coloring agent (i.e., a chromophore). Water clouds are very rarely seen since they form very deep in the atmosphere, and are thus hidden by the upper level clouds.

Do Jupiter's cloud produce rain/snow?

Yes! While it is difficult to directly observe rain/snow, several simulations of clouds on Jupiter predict an abundance of precipitation. Also, there are several evidences of thunderstorms and lightning on Jupiter, and these are thought to be generated from ice particles rubbing against each other to produce electric charge (in a similar fashion to how lightning is generated on Earth).

How do vortices form on Jupiter?

Vortices on Jupiter are formed in a similar way to hurricanes/cyclones on Earth. Storms below clouds will cause these clouds to move (flowing outward from a central location for anti-cyclones, and vice-versa for cylones). Jupiter's rotation will cause Coriolis force to act on these moving clouds, and start to rotate them, creating vortices.

The project

Why is the project named the "Jovian Vortex Hunter"?
In Roman Mythology, Jupiter (or Jove) was the god of lightning and thunder. Therefore, in recent times, the adjective to describe things on Jupiter is "jovian", or "of Jove". In this project, we are hunting for vortices on Jupiter, or jovian vortices!

How are these images that I see created?

The images that you see are from the Juno spacecraft (specifically images taken by the JunoCam instrument). You can check out more of the images from JunoCam in the official website. You can also download the raw images and process them yourself! For this project, we get the raw data from Juno, project each image onto a map and then make square cuts in these maps. You can check out the code for processing these images here

What is the physical span/size of the images I am looking at?

Each image measures about 7000 km on each side.

What are you going to do with the classification data?

The classification data will tell us what kinda of vortices are present in Jupiter and where they form. With this data, we can create a distribution of different types of vortices, and identify regions where some types are more prominent than others. For example, we think that brown barges are more likely to form in belts (the darker cloud bands), since the belt regions have cyclonic vorticity. This project will help us quantify these statements.

Furthermore, we are training a deep neural network to learn about the different atmospheric features in the images. Our ultimate goal is to create a catalogue of the different types of vortices that are present in the jovian atmosphere, and understand what the diversity of the associated features are. For example, we want to study how vortices that form in different regions may be similar (in color, shape, etc.), and consequently understand what is the underlying physics that forms them.

Why do different images have different color balancing?
JunoCam takes images in three different color filters (red, green and blue) that are then combined together into a color image during the post-processing stage. Therefore, JunoCam data does not provide a 'true-color' representation of the data, and the combined color images are modified in a way to mimic what we would see. Therefore, in some edge cases, or where the lighting geometry changes, there are variations in the perceived color of the feature.

What is a 'Perijove'?
The point in orbit of the Juno spacecraft that is closest to the planet is called a 'perijove', while the point that is furthest away is an 'apojove'. Juno takes 53 days to do one full orbit around the planet, and whenever it approaches its perijove, the instruments turn on and the spacecraft will start recording data. About 2 hours after each perijove, the data collection is stopped, since the spacecraft will be further away from the planet, where the radiation is strong enough to affect its instruments. Therefore, we categorize our images using the 'perijove' value since that corresponds to the time at which the images were taken by JunoCam.

Technical questions

Who do I talk to if I have a question about the project?
If you're having technical difficulties, please check the Technical Difficulties Talk board to see if others are having an issue, or start a new thread. If you have a question about an interesting image that you saw, you can add it to a Collection or mention it in the Unusual Vortices Talk board.