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NASA/JPL-Caltech/SETI Institute

Jupiter's Moon Europa May Be Streaked With Sea Salt

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NASA/JPL-Caltech/SETI Institute

Europa, one of Jupiter’s many moons, appears crisscrossed with a dark substance, like caramel drizzled on a scoop of ice cream. Long a mystery to scientists, these streaks may be sea salt from an ocean beneath the planet’s icy surface, a new study finds. 

At NASA’s Jet Propulsion Laboratory (JPL) in California, two scientists have built a kind of “Europa in a can,” a miniature simulation of a patch of Europa’s surface that mimics the moon’s temperature, pressure, and radiation exposure. In a new study in Geophysical Research Letters, they lay out evidence from their experiments that Europa’s distinctive discoloration stems from sodium chloride rising from the ocean below, in a process that may provide further evidence of the moon’s habitability. 

A laboratory setup at NASA’s Jet Propulsion Laboratory that mimics Europa’s conditions. Image Credit: NASA/JPL-Caltech

JPL’s Kevin Hand and Robert Carlson placed regular salt in a vacuum chamber at Europa’s surface temperature (-280 degrees Fahrenheit) and blasted it with an electron beam to mimic the radiation present on the moon. Ten hours later—the Europa equivalent of a century on Earth—the white salt samples turned yellow-brown, similar to the appearance of the streaks on Europa seen by NASA’s Galileo mission. The longer the samples stayed in the vacuum exposed to the radiation, the darker they became. 

There’s no telescope on Earth that can observe Europa accurately enough to prove this hypothesis, but it does bolster the case for sending future spacecraft there to explore. Scientists theorize that Europa could be one of our best chances of finding life in the wide universe beyond Earth’s atmosphere, and research like this can help determine whether the moon has a good shot at being habitable before we send a multi-billion-dollar probe.  

[h/t: Gizmodo]

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science
6 Radiant Facts About Irène Joliot-Curie
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Hulton Archive/Getty Images

Though her accomplishments are often overshadowed by those of her parents, the elder daughter of Marie and Pierre Curie was a brilliant researcher in her own right.

1. SHE WAS BORN TO, AND FOR, GREATNESS.

A black and white photo of Irene and Marie Curie in the laboratory in 1925.
Irène and Marie in the laboratory, 1925.
Wellcome Images, Wikimedia Commons // CC BY 4.0

Irène’s birth in Paris in 1897 launched what would become a world-changing scientific dynasty. A restless Marie rejoined her loving husband in the laboratory shortly after the baby’s arrival. Over the next 10 years, the Curies discovered radium and polonium, founded the science of radioactivity, welcomed a second daughter, Eve, and won a Nobel Prize in Physics. The Curies expected their daughters to excel in their education and their work. And excel they did; by 1925, Irène had a doctorate in chemistry and was working in her mother’s laboratory.

2. HER PARENTS' MARRIAGE WAS A MODEL FOR HER OWN.

Like her mother, Irène fell in love in the lab—both with her work and with another scientist. Frédéric Joliot joined the Curie team as an assistant. He and Irène quickly bonded over shared interests in sports, the arts, and human rights. The two began collaborating on research and soon married, equitably combining their names and signing their work Irène and Frédéric Joliot-Curie.

3. SHE AND HER HUSBAND WERE AN UNSTOPPABLE PAIR.

Black and white photo of Irène and Fréderic Joliot-Curie working side by side in their laboratory.
Bibliothèque Nationale de France, Wikimedia Commons // Public Domain

Their passion for exploration drove them ever onward into exciting new territory. A decade of experimentation yielded advances in several disciplines. They learned how the thyroid gland absorbs radioiodine and how the body metabolizes radioactive phosphates. They found ways to coax radioactive isotopes from ordinarily non-radioactive materials—a discovery that would eventually enable both nuclear power and atomic weaponry, and one that earned them the Nobel Prize in Chemistry in 1935.

4. THEY FOUGHT FOR JUSTICE AND PEACE.

The humanist principles that initially drew Irène and Frédéric together only deepened as they grew older. Both were proud members of the Socialist Party and the Comité de Vigilance des Intellectuels Antifascistes (Vigilance Committee of Anti-Fascist Intellectuals). They took great pains to keep atomic research out of Nazi hands, sealing and hiding their research as Germany occupied their country, Irène also served as undersecretary of state for scientific research of the Popular Front government.

5. SHE WAS NOT CONTENT WITH THE STATUS QUO.

Irène eventually scaled back her time in the lab to raise her children Hélène and Pierre. But she never slowed down, nor did she stop fighting for equality and freedom for all. Especially active in women’s rights groups, she became a member of the Comité National de l'Union des Femmes Françaises and the World Peace Council.

6. SHE WORKED HERSELF TO DEATH.

Irène’s extraordinary life was a mirror of her mother’s. Tragically, her death was, too. Years of watching radiation poisoning and cancer taking their toll on Marie never dissuaded Irène from her work. In 1956, dying of leukemia, she entered the Curie Hospital, where she followed her mother’s luminous footsteps into the great beyond.

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Food
Researchers Pinpoint the Genes Behind the Durian's Foul Stench
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iStock

Durian is a popular fruit in parts of southeast Asia. It's also known for having the most putrid, off-putting odor of any item sold in the produce section. Even fans of durian know why the fruit gets a bad rap, but what exactly causes its divisive scent is less obvious. Determined to find the answer, a team of researchers funded by "a group of anonymous durian lovers" mapped the fruit's genome, as reported by the BBC.

The study, published in the journal Nature Genetics [PDF], contains data from the first-ever complete genetic mapping of a durian fruit. It confirms that durian's excess stinkiness comes from sulfur, a chemical element whose scent is often compared to that of rotten eggs.

Analysis of the fruit's chemical makeup has been done in the past, so the idea that sulfur is a major contributor to its signature smell is nothing new. What is new is the identification of the specific class of sulfur-producing genes. These genes pump out sulfur at a "turbocharged" rate, which explains why the stench is powerful enough to have durian banned in some public areas. It may seem like the smell is a defense mechanism to ward off predators, but the study authors write that it's meant to have the opposite effect. According to the paper, "it is possible that linking odor and ripening may provide an evolutionary advantage for durian in facilitating fruit dispersal." In other words, the scent attracts hungry primates that help spread the seeds of ripe durian fruits by consuming them.

The revelation opens the door to genetically modified durian that are tweaked to produce less sulfur and therefore have a milder taste and smell. But such a product would likely inspire outrage from the food's passionate fans. While the flavor profile has been compared to rotten garbage and dead animal meat, it's also been praised for its "overtones of hazelnut, apricot, caramelized banana, and egg custard" by those who appreciate its unique character.

[h/t BBC]

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