This enhanced-color composite photo shows Jupiter’s south pole from NASA’s Juno spacecraft 32,000 miles above the gas giant. The oval features are cyclones up to 600 miles wide.
This enhanced-color composite photo shows Jupiter’s south pole from NASA’s Juno spacecraft 32,000 miles above the gas giant. The oval features are cyclones up to 600 miles wide.
NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles

Much of What We Thought About Jupiter Is Wrong

This enhanced-color composite photo shows Jupiter’s south pole from NASA’s Juno spacecraft 32,000 miles above the gas giant. The oval features are cyclones up to 600 miles wide.
This enhanced-color composite photo shows Jupiter’s south pole from NASA’s Juno spacecraft 32,000 miles above the gas giant. The oval features are cyclones up to 600 miles wide.
NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles

Scientists have had time to study the data returned from the NASA spacecraft Juno and are discovering that pretty much everything they thought they knew about Jupiter’s interior is wrong. “I think we’re all sort of feeling the humility and humbleness,” said Scott Bolton, the principal investigator of Juno, during a press teleconference today, May 25. “It is making us rethink how giant planets work not only in our system but throughout the galaxy.”

The findings from Juno’s initial Jupiter orbits were published today in the journals Science and Geophysical Research Letters. The latter is a special issue devoted to Juno data and includes more than two dozen reports.


Juno, which launched in 2011 and entered Jupiter's orbit on July 4, 2016, is the first spacecraft to give scientists a real view of Jupiter’s poles, and what they’ve found is unlike anything expected.

“Jupiter from the poles doesn’t look anything like it does from the equator,” Bolton said.

Images reveal that Jupiter’s famous bands do not continue to the north and south poles. Rather, the poles are characterized by a bluish hue, chaotic swirls, and ovular features, which are Texas-sized ammonia cyclones. The precise mechanism behind them is unknown. Their stability is equally a mystery. As the Juno mission progresses, repeat visits to the poles and new data on the evolution of the cyclones will answer some of these questions.

The poles aren't identical, either. “The fact that the north and south pole don’t really look like each other is also a puzzle to us,” Bolton said.

One interesting observation was a happy accident. Because of Juno’s unique orbit, the spacecraft always crosses a terminator—that is, the line dividing where the planet is in full illumination of the Sun, and the far side, in total darkness. This is useful because topological relief can be seen at this line. (To see this in action, look through a telescope at a half-full moon. The shadows where light meets dark give a vivid sense of the heights of mountains and the depths of craters.) During an orbit, there happened to be a 4300-mile-wide storm at Jupiter’s terminator near the north pole, and scientists noticed shadows. The storm was towering over its cloud surroundings like a tornado on a Kansas prairie.


Jupiter's core with metallic hydrogen fluid envelope
What may lie within the heart of Jupiter: a possible inner “rock” core surrounded by metallic hydrogen and an outer envelope of molecular hydrogen, all hidden beneath the visible cloud deck.

Bolton explained that the goal of Juno is "looking inside Jupiter pretty much every way we know how.” Juno carries an instrument called a microwave radiometer, designed to see through Jupiter’s clouds and to collect data on the dynamics and composition of its deep atmosphere. (The instrument is sensitive to water and ammonia but is presently looking only at ammonia.) So far, the data are mystifying and wholly unexpected. Most scientists previously believed that just below the clouds, Jupiter’s atmosphere is well mixed. Juno has found just the opposite: that levels of ammonia vary greatly, and that the structure of the atmosphere does not match the visible zones and belts. Ammonia is emanating from great depths of the planet and driving weather systems.

Scientists still don’t know whether Jupiter has a core, or what it’s composed of if it exists. For insight, they’re studying the planet’s magnetosphere. Deep inside the gas giant, the pressure is so great that the element hydrogen has been squeezed into a metallic fluid. (Atmospheric pressure is measured in bars. Pressure at the surface of the Earth is one bar. On Jupiter, it’s 2 million. And at the core it would be around 40 million bars.) The movement of this liquid metallic hydrogen is thought by scientists to create the planet’s magnetic field. By studying the field, Juno can unlock the mysteries of the core’s depth, size, density, and even whether it exists, as predicted, as a solid rocky core. “We were originally looking for a compact core or no core,” Bolton said, “but we’re finding that it’s fuzzy—perhaps partially dissolved.”

Jupiter’s magnetosphere is the second-largest structure in the solar system, behind only the heliosphere itself. (The heliosphere is the total area influenced by the Sun. Beyond it is interstellar space.) So far, scientists are dumbfounded by the strength of the magnetic field close to the cloud tops—and by its deviations. “What we’ve found is that the magnetic field is both stronger than where we expected it to be strong, and weaker where we expected it to be weak,” said Jack Connerney, the deputy principal investigator of Juno.

Another paper today in Science revealed new findings about Jupiter’s auroras. The Earth’s auroras are Sun-driven, the result of the interaction of the solar winds and Earth’s magnetosphere. Jupiter’s auroras have been known for a while to be different, and related to the planet’s rotation. Juno has taken measurements of the magnetic field and charged particles causing the auroras, and has also taken the first images of the southern aurora. The processes at work are still unknown, but the takeaway is that the mechanics behind Jupiter’s auroras are unlike those of Earth, and call into question how Jupiter interacts with its environment in space.


An enhanced-color closeup of swirling waves of clouds, some just 4 miles across. Some of the small, bright high clouds seem to form squall lines, or a narrow band of high winds and storms associated with a cold front. They're likely composed of water and/or ammonia ice.
NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran

Understanding Jupiter is essential to understanding not only how our solar system formed, but how the new systems being discovered around stars form and operate as well. The next close approach of Jupiter will take place on July 11, when Juno flies directly over the famed Great Red Spot. Scientists hope to learn more about its depth, action, and drivers.

Juno already has us rewriting the textbooks, and it's only at the beginning of its orbital mission. It's slated to perform 33 polar orbits of Jupiter, each lasting 53.5 days. So far, it's completed only five. The spacecraft’s prime mission will end next year, at which time NASA will have to decide whether it can afford to extend the mission or to send Juno into the heart of Jupiter, where it will be obliterated. This self-destruct plunge would protect that region of space from debris and local, potentially habitable moons from contamination.

Bolton tells Mental Floss that the surprising findings really bring home the fact that to unlock Jupiter, this mission will need to be seen through to completion. “That’s what exciting about exploration: We’re going to a place we’ve never been before and making new discoveries … we’re just scratching the surface.” he says. “Juno is the right tool to do this. We have the right instruments. We have the right orbit. We’re going to win over this beast and learn how it works.”

This enhanced-color composite photo shows Jupiter’s south pole from NASA’s Juno spacecraft 32,000 miles above the gas giant. The oval features are cyclones up to 600 miles wide.
Stones, Bones, and Wrecks
Buckingham Palace Was Built With Jurassic Fossils, Scientists Find

The UK's Buckingham Palace is a vestige from another era, and not just because it was built in the early 18th century. According to a new study, the limestone used to construct it is filled with the fossilized remains of microbes from the Jurassic period of 200 million years ago, as The Telegraph reports.

The palace is made of oolitic limestone, which consists of individual balls of carbonate sediment called ooids. The material is strong but lightweight, and is found worldwide. Jurassic oolite has been used to construct numerous famous buildings, from those in the British city of Bath to the Empire State Building and the Pentagon.

A new study from Australian National University published in Scientific Reports found that the spherical ooids in Buckingham Palace's walls are made up of layers and layers of mineralized microbes. Inspired by a mathematical model from the 1970s for predicting the growth of brain tumors, the researchers created a model that explains how ooids are created and predicts the factors that limit their ultimate size.

A hand holding a chunk of oolite limestone
Australian National University

They found that the mineralization of the microbes forms the central core of the ooid, and the layers of sediment that gather around that core feed those microbes until the nutrients can no longer reach the core from the outermost layer.

This contrasts with previous research on how ooids form, which hypothesized that they are the result of sediment gathered from rolling on the ocean floor. It also reshapes how we think about the buildings made out of oolitic limestone from this period. Next time you look up at the Empire State Building or Buckingham Palace, thank the ancient microbes.

[h/t The Telegraph]

This enhanced-color composite photo shows Jupiter’s south pole from NASA’s Juno spacecraft 32,000 miles above the gas giant. The oval features are cyclones up to 600 miles wide.
Anne Dirkse, Flickr // CC BY-SA 2.0
10 Astonishing Things You Should Know About the Milky Way
Anne Dirkse, Flickr // CC BY-SA 2.0
Anne Dirkse, Flickr // CC BY-SA 2.0

Our little star and the tiny planets that circle it are part of a galaxy called the Milky Way. Its name comes from the Greek galaxias kyklos ("milky circle") and Latin via lactea ("milky road"). Find a remote area in a national park, miles from the nearest street light, and you'll see exactly why the name makes sense and what all the fuss is about. Above is not a sky of black, but a luminous sea of whites, blues, greens, and tans. Here are a few things you might not know about our spiraling home in the universe.


The Milky Way galaxy is about 1,000,000,000,000,000,000 kilometers (about 621,371,000,000,000,000 miles) across. Even traveling at the speed of light, it would still take you well over 100,000 years to go from one end of the galaxy to the other. So it's big. Not quite as big as space itself, which is "vastly, hugely, mind-bogglingly big," as Douglas Adams wrote, but respectably large. And that's just one galaxy. Consider how many galaxies there are in the universe: One recent estimate says 2 trillion.


artist's illustration of the milky way galaxy and its center
An artist's concept of the Milky Way and the supermassive black hole Sagittarius A* at its core.
ESA–C. Carreau

The Milky Way is a barred spiral galaxy composed of an estimated 300 billion stars, along with dust, gas, and celestial phenomena such as nebulae, all of which orbits around a hub of sorts called the Galactic Center, with a supermassive black hole called Sagittarius A* (pronounced "A-star") at its core. The bar refers to the characteristic arrangement of stars at the interior of the galaxy, with interstellar gas essentially being channeled inward to feed an interstellar nursery. There are four spiral arms of the galaxy, with the Sun residing on the inner part of a minor arm called Orion. We're located in the boondocks of the Milky Way, but that is OK. There is definitely life here, but everywhere else is a question mark. For all we know, this might be the galactic Paris.


If you looked at all the spiral galaxies in the local volume of the universe, the Milky Way wouldn't stand out as being much different than any other. "As galaxies go, the Milky Way is pretty ordinary for its type," Steve Majewski, a professor of astronomy at the University of Virginia and the principal investigator on the Apache Point Observatory Galactic Evolution Experiment (APOGEE), tells Mental Floss. "It's got a pretty regular form. It's got its usual complement of star clusters around it. It's got a supermassive black hole in the center, which most galaxies seem to indicate they have. From that point of view, the Milky Way is a pretty run-of-the-mill spiral galaxy."


On the other hand, he tells Mental Floss, spiral galaxies in general tend to be larger than most other types of galaxies. "If you did a census of all the galaxies in the universe, the Milky Way would seem rather unusual because it is very big, our type being one of the biggest kinds of galaxies that there are in the universe." From a human perspective, the most important thing about the Milky Way is that it definitely managed to produce life. If they exist, the creatures in Andromeda, the galaxy next door (see #9), probably feel the same way about their own.


John McSporran, Flickr // CC BY 2.0

We have a very close-up view of the phenomena and forces at work in the Milky Way because we live inside of it, but that internal perspective places astronomers at a disadvantage when it comes to determining a galactic pattern. "We have a nice view of the Andromeda galaxy because we can see the whole thing laid out in front of us," Majewski says. "We don't have that opportunity in the Milky Way."

To figure out its structure, astronomers have to think like band members during a football halftime show. Though spectators in the stands can easily see the letters and shapes being made on the field by the marchers, the band can't see the shapes they are making. Rather, they can only work together in some coordinated way, moving to make these patterns and motions on the field. So it is with telescopes and stars.


Interstellar dust further stymies astronomers. "That dust blocks our light, our view of the more distant parts of the Milky Way," Majewski says. "There are areas of the galaxy that are relatively obscured from view because they are behind huge columns of dust that we can't see through in the optical wavelengths that our eyes work in." To ameliorate this problem, astronomers sometimes work in longer wavelengths such as radio or infrared, which lessen the effects of the dust.


Astronomers can make pretty reasonable estimates of the mass of the galaxy by the amount of light they can see. They can count the galaxy's stars and calculate how much those stars should weigh. They can account for all the dust in the galaxy and all of the gas. And when they tally the mass of everything they can see, they find that it is far short of what is needed to account for the gravity that causes the Milky Way to spin.

In short, our Sun is about two-thirds of the way from the center of the galaxy, and astronomers know that it goes around the galaxy at about 144 miles per second. "If you calculate it based on the amount of matter interior to the orbit of the Sun, how fast we should be going around, the number you should get is around 150 or 160 kilometers [93–99 miles] per second," Majewski says. "Further out, the stars are rotating even faster than they should if you just account for what we call luminous matter. Clearly there is some other substance in the Milky Way exerting a gravitational effect. We call it dark matter."


Dark matter is a big problem in galactic studies. "In the Milky Way, we study it by looking at the orbits of stars and star clusters and satellite galaxies, and then trying to figure out how much mass do we need interior to the orbit of that thing to get it moving at the speed that we can measure," Majewski says. "And so by doing this kind of analysis for objects at different radii across the galaxy, we actually have a fairly good idea of the distribution of the dark matter in the Milky Way—and yet we still have no idea what the dark matter is."


andromeda galaxy
The Andromeda galaxy
ESA/Hubble & NASA

Sometime in the next 4 or 5 billion years, the Milky Way and Andromeda galaxies will smash into each other. The two galaxies are about the same size and have about the same number of stars, but there is no cause for alarm. "Even though there are 300 billion stars in our galaxy and a comparable number, or maybe more, in Andromeda, when they collide together, not a single star is expected to hit another star. The space between stars is that vast," Majewski says.


There are countless spacecraft and telescopes studying the Milky Way. Most famous is the Hubble Space Telescope, while other space telescopes such as Chandra, Spitzer, and Kepler are also returning data to help astronomers unlock the mysteries of our swirling patch of stars. The next landmark telescope in development is NASA's James Webb Space Telescope. It should finally launch in 2019. Meanwhile, such ambitious projects as APOGEE are working out the structure and evolution of our spiral home by doing "galactic archaeology." APOGEE is a survey of the Milky Way using spectroscopy, measuring the chemical compositions of hundreds of thousands of stars across the galaxy in great detail. The properties of stars around us are fossil evidence of their formation, which, when combined with their ages, helps astronomers understand the timeline and evolution of the galaxy we call home. 


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