Jupiter is a monster. Honestly, there’s no other way to put it. It’s a planet-sized storm factory that could swallow 1,300 Earths without breaking a sweat. For decades, we thought we had a pretty good handle on what was happening under those iconic orange and white stripes. We were wrong.
Enter the NASA Juno space probe.
When Juno pulled into orbit around the gas giant in 2016, it wasn’t just there to take pretty pictures—though it has certainly done that. It was there to play detective. Since then, it has survived radiation levels that would fry a standard laptop in seconds and peered through clouds so thick they’ve hidden the planet’s secrets for billions of years. As of January 2026, the mission is still screaming along, having recently dodged a massive budget axe to continue its work through the end of its extended mission.
The "Fuzzy" Core Mystery
One of the biggest things people get wrong about Jupiter is the idea that it’s just a big ball of gas with a solid rock in the middle. Most textbooks used to show a neat, rocky core about the size of Earth.
Juno’s gravity science experiments basically took that textbook and threw it out the window. By measuring tiny wobbles in Juno's trajectory, scientists like Scott Bolton, the mission's Principal Investigator, discovered that Jupiter has a "diluted" or "fuzzy" core. It’s not a solid hunk of rock; it’s a giant, messy region of heavy elements mixed with liquid metallic hydrogen. It stretches out across nearly half the planet's radius.
Why does this matter? Well, it suggests something violent happened early on. One leading theory is that a protoplanet—something ten times the mass of Earth—slammed head-on into Jupiter billions of years ago, stirring the core up like a spoon in a bowl of soup.
Shallow Lightning and Ammonia Hail
We always assumed Jupiter’s weather was just a bigger version of Earth’s. You have water, it evaporates, it rains. Simple, right?
Not quite. Juno found something called "shallow lightning." On Earth, lightning comes from water clouds. But on Jupiter, Juno spotted flashes originating much higher up in the atmosphere, where it’s way too cold for liquid water to exist.
Instead, it’s a weird "mushball" situation. Ammonia acts like an antifreeze, melting water ice crystals even at high altitudes. These ammonia-water droplets fall as heavy slushy hail, or mushballs, dragging nitrogen and water deep into the interior. It’s a chemical elevator that keeps the upper atmosphere surprisingly dry while locking the good stuff deep down.
Those Impossible Polar Cyclones
Before Juno, we’d never really seen Jupiter’s poles. We assumed they’d look like Saturn’s—a nice, orderly hexagon.
What Juno found was a mosh pit.
At the north pole, there’s one central cyclone surrounded by eight smaller ones, each thousands of miles wide. They don't merge. They don't disappear. They just sit there, bumping into each other like bumper cars at a cosmic fair. Recent data from Perijove 69 in early 2025 showed that these storms actually oscillate and drift westward, held in a delicate gravitational dance that scientists are still trying to model accurately.
The Moon Pivot: From Jupiter to Io and Europa
Juno was originally supposed to die in 2021. The plan was a "death dive" into Jupiter to prevent any accidental contamination of the icy moons. But the spacecraft was in such good shape that NASA extended the mission, shifting the focus to the Galilean moons: Ganymede, Europa, and Io.
The Fires of Io
In late 2024 and throughout 2025, Juno did something incredible. It flew within 930 miles of Io, the most volcanic place in the solar system.
What it saw was terrifying. The JIRAM (Jovian Infrared Auroral Mapper) instrument detected a massive hotspot near the south pole that’s larger than Lake Superior. This single volcanic feature pumps out six times more energy than all the power plants on Earth combined. Honestly, the surface of Io is being constantly paved over by fresh lava. Juno’s data suggests that about 10% of the moon’s surface is sitting on top of active, "mushy" magma chambers.
📖 Related: Apple Maps in Browser: Is It Actually Better Than Google Maps Yet?
The Ice of Europa
While Io is a hellscape, Europa is an icebox. Juno’s flybys provided high-resolution shots of the "Manannán" crater and weird, crisscrossing ridges that look like giant scratches. The goal here was to hunt for water plumes—basically giant space geysers—and to help the Europa Clipper mission (slated to arrive later this decade) know where to look for life-supporting chemistry.
How Juno Survives the Death Zone
You can't just "fly" to Jupiter. The radiation environment is so intense that it’s like standing inside a giant microwave.
To survive, Juno is built like a tank. Its "brain" is encased in a 400-pound titanium vault. Even then, the radiation eventually eats away at everything. The JunoCam—the camera that gives us those swirl-filled masterpieces—has suffered "noise" and hardware degradation over the years. In late 2023, the team actually had to perform a "deep-space move" to essentially reboot and warm up the camera to fix some of its imaging issues.
Also, Juno is a bit of a giant. Its three solar panels stretch out 66 feet, making it the most distant solar-powered probe in history. At Jupiter, the sun is 25 times fainter than it is on Earth, so those panels have to be massive just to keep the lights on.
The 2026 Budget Scare
For a minute there, it looked like Juno was toast. In mid-2025, a proposed budget for the 2026 fiscal year threatened to cut NASA’s planetary science funding by nearly 50%. This would have effectively ended the Juno mission early, along with several other iconic probes.
Luckily, in January 2026, Congress stepped in. They passed a "minibus" spending bill that restored $24.4 billion to NASA, specifically protecting operational missions like Juno. This means the team can keep collecting data until the propellant runs out or the radiation finally wins.
What’s Next for the Mission?
The current "Extended Mission" is funded through late 2025/early 2026. The next phase, if a third extension is granted, would focus on the Jovian rings and the "inner" moons like Amalthea and Metis. These are tiny, potato-shaped rocks that we’ve barely seen up close.
There’s even a wild proposal being floated by scientists like Avi Loeb to use Juno to intercept an interstellar object, though that’s more of a "math-on-a-napkin" idea for now.
Actionable Insights for Space Enthusiasts
If you want to stay on top of what Juno is doing, don't just wait for the news. You can actually participate.
- Process Raw Data: NASA uploads the "raw" JunoCam files to the Mission Juno website. You don't need a PhD; some of the most famous images of Jupiter were processed by hobbyists using Photoshop.
- Track the Perijoves: Juno's orbit is highly elliptical. It spends most of its time far away and then "dives" close to the planet every 33 to 53 days. These are called Perijoves. Mark your calendar for the next one to see the freshest images.
- Use NASA’s Eyes: Download the "NASA’s Eyes on the Solar System" app. It lets you see exactly where Juno is in real-time, its speed, and what its instruments are pointing at.
The NASA Juno space probe has proved that Jupiter is far more complex than we ever dreamed. It’s not just a gas giant; it’s a dynamic, evolving world with a messy heart and moons that behave like planets. We're lucky it's still up there.