NASA’s Juno Takes Temperature of Jupiter’s Fiery Moon Io - UNIVERSE

TThe north polar region of Jupiter’s volcanic moon Io was captured by NASA’s Juno during the spacecraft’s 57th close pass of the gas giant on Dec. 30, 2023. Data from that flyby and one on Feb. 3, 2024, is helping scientists understand Io’s interior.

Image data: NASA/JPL-Caltech/SwRI/MSSS Image processing by Gerald Eichstädt

Lee esta historia en español aquí.

NASA’s Juno mission has provided the first measurements of the temperature below the surface of Jupiter’s moon Io, revealing significant heating within the shallow subsurface of the most volcanically active world in the solar system. Collected during two close flybys, the data also shows that most of Io’s surface is remarkably smooth and composed of material of very low density.

Published Wednesday in the Journal of Geophysical Research: Planets, these findings break new observational ground for both fiery and icy worlds beyond our planet.

Io’s extreme volcanism is powered by tidal heating. The moon is constantly stretched and squeezed by Jupiter’s immense gravity as it travels its slightly elliptical orbit, generating internal heat output many times greater than Earth’s. Until now, virtually everything known about that heat came from infrared observations, which sense only the temperature of the top surface. The latest findings are derived from data collected by the spacecraft’s Microwave Radiometer (MWR) instrument.

“The Juno Microwave Radiometer directly observed Io’s heat output by looking below the surface,” said Scott Bolton, study coauthor and Juno’s principal investigator at Southwest Research Institute in San Antonio. “The surprising discovery that we could see below a rocky moon’s surface has important implications for studying Earth’s volcanoes. Juno has taught us that if we look with an MWR-type instrument near a volcano on Earth, we might see a similar signature in the subsurface temperature gradient, providing new information on how terrestrial volcanoes work.”

This map represents data captured by the Microwave Radiometer instrument aboard NASA’s Juno, indicating heat rising from just beneath the surface of Jupiter’s moon Io. The colors illustrate a distinct temperature gradient across the moon, with the most extreme, localized heat output in red.

NASA/JPL-Caltech/SwRI/USGS

Fire, ice

Juno’s Microwave Radiometer was designed by Bolton to peer beneath Jupiter’s cloud tops to investigate the dynamics and composition of the gas giant’s deep atmosphere. The MWR’s six microwave antennas serve as a single instrument, simultaneously detecting microwaves at a wide range of wavelengths, from about half an inch to 20 inches (1.3 to 51 centimeters). During the mission’s extended phase, the MWR instrument has provided the opportunity to observe three of the planet’s Galilean moons: Ganymede, Europa, and Io.

“The technique is novel in that each wavelength explores different depths, providing a new way to characterize the deep atmosphere of giant planets and the subsurface crusts of icy and rocky moons,” said Bolton. “At Ganymede and Europa, we explored tens of miles below the surface, assuming their ice shells were mostly pure water, but the ability to probe into the volcanic rock at Io was an unexpected discovery.”

During flybys on Dec. 30, 2023, and Feb. 3, 2024, the solar-powered Juno spacecraft came within about 930 miles (1,500 kilometers) of the moon’s surface.

“The instrument measured Io’s thermal emission at depths ranging from a few inches down to tens of feet. Everywhere we looked, we found the temperature rising by more than 40 degrees Fahrenheit just several feet into the surface — a gradient far steeper than solar heating alone can explain,” said Shannon Brown, the paper’s lead author at NASA’s Jet Propulsion Laboratory in Southern California.

The data suggests two possible explanations. First, heat could be rising steadily through a conductive crust. While this background heat flow — measured at 1 to 3 watts per square meter — is relatively gentle on a local scale (roughly equivalent to a small nightlight glowing under every square yard), across the entire moon it represents a release of energy up to 30 times Earth’s average. Alternatively, the signal could be coming from cooling lava flows, capped by roughly 30 to 35 feet (9 to 11 meters) of solidified crust, that cover about 10% of the moon’s surface at any given time.

“Io provides a unique window into learning how tidal heating works throughout the cosmos, a fundamental process that provides energy and heat to worlds that are far from their parent star,” said Bolton. “This process can not only create the most volcanic body in the solar system, in the case of Io, but also fuels the subsurface oceans on the moons of giant planets, such as Europa and Ganymede. Up until this point we could only observe the heat escaping at the surface or through eruptions. Now we can characterize how the heat is moving from the interior toward the surface.” 

This graphic illustrates the areas of Io sampled by the Microwave Radiometer instrument aboard NASA’s Juno spacecraft during two close flybys of the Jovian moon.

NASA/JPL-Caltech/SwRI/USGS

Great plains of Io

Another big insight gained from the two flybys is just how smooth Io is. Prior to the recent findings, the moon was known for its tall mountains, but the MWR indicates that apart from this visible topography, the surface features expansive smooth patches that stretch for 60 miles (100 kilometers) or more. Because Juno flew by overlapping regions of Io at different angles, the team was able to map how the surface reflects microwaves, much like an airline passenger might see the ocean flash with sunlight only at specific angles.

“Away from its mountains, the surface is more like the Great Plains of North America, and even though Io is a rocky body, the surface material has a very low density — more like pumice or a fluffy volcanic ash than solid rock,” said Brown.

More about Juno

A division of Caltech in Pasadena, California, JPL manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute. Juno is part of NASA’s New Frontiers Program, which is managed at the agency’s Marshall Space Flight Center in Huntsville, Alabama, for the NASA’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft. More information about Juno is at: https://science.nasa.gov/mission/juno 

Source: NASA’s Juno Takes Temperature of Jupiter’s Fiery Moon Io - NASA

Same Carcinogen, Different Cancer: Why Your Genes Decide How Damage Turns Into Tumors

Most smokers never get lung cancer. Some people who’ve never touched a cigarette do. That mismatch between exposure and outcome has puzzled cancer researchers for decades, and it’s usually chalked up to some vague combination of “genetics and bad luck.” A new study published in Nature, led by researchers at the University of Cambridge working with the University of Edinburgh and collaborators across Europe and the US, offers the first real, direct evidence for what that genetic influence actually looks like, and it’s more specific than anyone expected.

The problem with studying this in people

Cancer starts when DNA accumulates mutations, errors that let cells grow uncontrollably and ignore the signals that would normally tell a damaged cell to die. Things like cigarette smoke and UV light drive up how much DNA damage a person accumulates, while inherited genetic variation can influence how many of those mutations actually stick. But testing that idea directly in humans is nearly impossible: no two people share an identical lifestyle, environment, and lifetime exposure history, so it’s very hard to isolate genetics as the variable that matters.

A cleaner experiment

To get around that, the team bred four different strains of mice with varying natural susceptibility to liver cancer, spanning roughly the same range of genetic diversity you’d see across human populations. Every mouse then received an identical dose of diethylnitrosamine, a liver carcinogen found in tobacco smoke and some processed foods, at exactly the same age. Because the exposure, timing, and dose were identical across all four strains, any differences that showed up afterward could be attributed to genetic background rather than lifestyle or environment, the variable that’s impossible to control for in human studies.

The researchers then sequenced the genomes of nearly 600 resulting tumors, along with examining untreated mice from each strain to track spontaneous tumor formation, and used that data to reconstruct how each individual tumor evolved from its original cancer-triggering mutation.

Same starting point, different roads

Across all four mouse strains, tumors nearly always picked up a driver mutation that activated the same core cancer-promoting signaling cascade, known as the MAPK pathway, a chain of molecular signals that governs cell growth and differentiation and shows up in a huge range of cancer types.

But that’s where the similarity ended. Depending on which strain a tumor arose in, the specific mutation driving that MAPK activation differed, and that choice of mutation had knock-on effects: it altered which other cancer-associated signaling pathways got switched on, and it strongly influenced whether the tumor’s entire chromosome set ended up doubling, an event called whole-genome duplication that’s associated with more aggressive cancer behavior.

In other words, inherited genetic background didn’t just change whether cancer developed. It shaped the entire evolutionary trajectory the tumor took to get there, funneling the same initial DNA damage down genuinely different molecular paths depending on the animal’s genetic makeup.

What this could mean for cancer prevention and treatment

Because inherited genetics shaped both the mutations tumors acquired and the biological pathways they ended up relying on, the researchers argue this has real implications beyond basic biology. If your genetic background steers which molecular route a tumor takes, it’s plausible that it also shapes how that tumor would respond to specific cancer drugs, many of which are designed to target particular pathways like MAPK signaling.

That points toward cancer prevention, screening, and treatment strategies that account more explicitly for a person’s inherited genetics and population-level genetic diversity, rather than treating cancer risk and cancer treatment response as largely uniform across a given environmental exposure.

The researchers are careful to note that this was done in mice, and translating the findings to humans will require further work. But it’s a rare case of directly proving, rather than just statistically suggesting, that the same environmental insult can be steered down meaningfully different cancer-causing paths purely by the genetic hand an individual was dealt.

Source: S.J. Aitken et al., “Genetic background sets the trajectory of experimental cancer evolution,” Nature, published 22 July 2026. Read the full paper: https://www.nature.com/articles/s41586-026-10821-z 

Source: Same Carcinogen, Different Cancer: Why Your Genes Decide How Damage Turns Into Tumors