Know Your Planet And Eat It Too

A Jupiter cake made by Rhiannon, who writes the Cakecrumbs blog, shows the giant planet’s layered atmosphere and interior in a fun and realistic way. Click for recipe. Credit: Rhiannon

I had no idea Jupiter had a mud cake core surrounded by almond butter cake and enveloped with a blue-tinted vanilla Madeira sponge. Topped off with vanilla buttercream and marshmallow icing, it’s the first planet that’s ever made my mouth water.

The Great Red Spot inspired Rhiannon to pick Jupiter for her cake. The iconic feature is instantly recognizable. She used ivory, brown and maroon edible ink to dry brush the Spot and other atmospheric features like belts and vortices on the outer layer of marshmallow fondant (icing). Credit: Rhiannon /

Rhiannon, who writes the Cakecrumbs blog, had two passions as a child, animals and the solar system. A self-taught cook and cake decorator, she recently created what she calls her “Jupiter Structural Layer Cake” based on current knowledge of the planet’s atmosphere and interior.

Why Jupiter? It wouldn’t surprise you to know that the Great Red Spot – that huge storm more than twice the size of Earth that’s been whirling around up there the past few hundred years – has always been one of her favorite outer space personalities.

Jupiter concentric layer cake tutorial

Painting on the Red Spot and many other atmospheric details, all based on photos of the planet over many years, took 8 hours, just 2 hours shy of one complete rotation of the real Jupiter. That’s dedication.

You’ll have to watch the video to appreciate the details (three baking steps were required), but to create the sphere, she joined two cake hemispheres with buttercream.

The non-cake Jupiter spans nearly 87,000 miles across and is striped with jet-stream like belts of ammonia ice clouds. Earth is shown for comparison. Credit: NASA

Rhiannon cautions that her cake is “totally not to scale”, but she’s got the details down. Jupiter’s marshmallow cream atmosphere is mostly hydrogen and helium with clouds made of ammonia ice and even water ice further down. All those lovely yellows, reds and oranges so lovingly applied with tiny brushstrokes of food coloring are likely trace amounts of compounds of sulfur, carbon and phosphorus in real life.

Below the clouds, Jupiter just gets weird. Its atmosphere reaches down for thousands of miles. In December 1995, NASA’s Galileo spacecraft released an Entry Probe toward the planet. As the craft descended into the maelstrom of Jovian clouds, it transmitted data back to the orbiter for just 58 minutes. At a depth of 373 miles (600 km), transmissions stopped as the machine was presumably crushed by the extreme atmospheric pressure. Pressures at the base of Jupiter’s atmosphere are 4 million times what we experience on Earth.

Cutaway showing both the cloudtops and the interior of Jupiter. About 75% of the planet’s weight is taken up by fluid metallic hydrogen. Jupiter’s composition is very similar to the sun’s, and like the sun, it’s very hot in the center, but not hot enough to ignite hydrogen and burn as a star.

It only gets more intense as you approach the core. At a certain depth, airy hydrogen is compressed by the vast amount of material above it into liquid molecular hydrogen (the blue cake layer). Below that we arrive at a truly exotic form of matter, liquid metallic hydrogen (white cake).

Under the extreme pressures and heat near the core, ordinary hydrogen gets squeezed so tightly, its electrons depart and move about just like they do in metals. And just as metals conduct electricity, so too this bizarre hydrogen cousin. If you could somehow touch it – impossible because it can’t be created on Earth – it would resemble liquid mercury.

Don’t care for Jupiter? How about a slice of Earth? This is one of Rhiannon’s earlier cakes. The slice shows the crust, mantle (red), outer core (yellow) and inner core. Credit: Rhiannon /

Jupiter’s intense magnetic field is thought to arise from the rapid spinning of this electric liquid. Deeper down, we meet a putative core of rock (mud cake), something like the Earth in composition, but 10-15 times more massive.

Have you had enough cake yet?


7 Responses

  1. Giorgio Rizzarelli

    That Jupiter cake (included the inner structure!) was one of the most cool things you ever shared, no kidding 😀

    1. astrobob

      That’s nice to hear. Thanks! I envision a whole family of planetary cakes. And why stop there? How about star types?

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