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.

TEXAS-SIZED AMMONIA CYCLONES ARE ONLY THE BEGINNING

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.

INTENSE PRESSURE SQUEEZES HYDROGEN INTO A METALLIC FLUID

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.
NASA/JPL-Caltech/SwRI

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.

JUNO ALREADY HAS US REWRITING THE TEXTBOOKS


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.”

Fossilized Fat Shows 550-Million-Year-Old Sea Creature May Have Been the World's First Animal

Ilya Bobrovskiy, the Australian National University
Ilya Bobrovskiy, the Australian National University

A bizarre sea creature whose fossils look like a cross between a leaf and a fingerprint may be Earth's oldest known animal, dating back 558 million years.

As New Scientist reports, researchers from the Australian National University (ANU) made a fortunate find in a remote region of Russia: a Dickinsonia fossil with fat molecules still attached. These odd, oval-shaped creatures were soft-bodied, had rib structures running down their sides, and grew about 4.5 feet long. They were as “strange as life on another planet,” researchers wrote in the abstract of a new paper published in the journal Science.

Another variety of fossil
Ilya Bobrovskiy, the Australian National University

Although Dickinsonia fossils were first discovered in South Australia in 1946, researchers lacked the organic matter needed to classify this creature. "Scientists have been fighting for more than 75 years over what Dickinsonia and other bizarre fossils of the Edicaran biota were: giant single-celled amoeba, lichen, failed experiments of evolution, or the earliest animals on Earth,” senior author Jochen Brocks, an associate professor at ANU, said in a statement.

With the discovery of cholesterol molecules—which are found in almost all animals, but not in other organisms like bacteria and amoebas—scientists can say that Dickinsonia were animals. The creatures swam the seas during the Ediacaran Period, 635 million to 542 million years ago. More complex organisms like mollusks, worms, and sponges didn’t emerge until 20 million years later.

The fossil with fat molecules was found on cliffs near the White Sea in an area of northwest Russia that was so remote that researchers had to take a helicopter to get there. Collecting the samples was a death-defying feat, too.

“I had to hang over the edge of a cliff on ropes and dig out huge blocks of sandstone, throw them down, wash the sandstone, and repeat this process until I found the fossils I was after,” lead author Ilya Bobrovskiy of ANU said. Considering that this find could change our understanding of Earth’s earliest life forms, it seems the risk was worth it.

[h/t New Scientist]

The Weird, Disturbing World of Snail Sex

iStock
iStock

Romance is rare in the animal kingdom. Instead of wooing their partners before copulating, male ducks force themselves onto females, depositing genetic material with spiky, corkscrew penises. Then, there's tardigrade sex, which is less violent but not exactly heartwarming. Females lay eggs into a husk of dead skin. The male then ejaculates onto the eggs while stroking the female, and the whole process can take up to an hour.

But you can't talk about disturbing mating rituals in nature without mentioning snails. If you're unfamiliar with snail sexuality, you may assume that snail sex falls on the vanilla side: The mollusks, after all, are famous for being slow-moving and they don't even have limbs. But if you have the patience to watch a pair of snails going at it, you'll notice that things get interesting.

The first factor that complicates snail sex is their genitalia. Snails are hermaphrodites, meaning individuals have both a male set and female set of parts, and any two snails can reproduce with each other regardless of sex. But in order for a couple of snails to make little snail babies, one of them needs to take on the role of the female. That's where the love dart comes in.

The love dart, technically called a gypsobelum, isn't exactly the Cupid's arrow the name suggests. It's a nail-clipping-sized spike that snails jab into their partners about 30 minutes before the actual sex act takes place. The sliver is packed with hormones that prepare the receiving snail's body for sperm. Depending on the species, only one snail might release the dart, or they both might in an attempt to avoid becoming the female of the pair. You can watch the action in the video below.

For sex to be successful, both snails must insert their penises into the other's vaginal tracts at the same time. Both snails deposit sperm, and the strength of the love dart ultimately determines whether or not that sperm fertilizes their partner's eggs.

That's assuming the snail survives the little love-stab. In human proportions, the love dart is the equivalent of a 15-inch knife. Fortunately, snails are resilient creatures, and gastropod researcher Joris Koene tells KQED he's only ever seen one snail die from the transfer.

Snails also have a way of making it up to their partners after skewering them with a hormone stick. Their sperm deposit contains a dose of fortifying nutrients, something scientists refer to as a nuptial gift. It may not equal the energy expended during sex, but its enough to give them a small post-coital boost.

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