A planet that suffers 475℃ beneath a thick acid atmosphere may be the last place you'd expect alien（外星的） life in our solar system. But one NASA scientist claims that extraterrestrials（天外来客） are most likely hiding on Venus amid conditions that are unbearable for humans. The new theory was put forward by the research scientist Dr Michelle Thaller. She says that possible signs of life have already been seen within the carbon-dioxide filled atmosphere, adding that she was absolutely certain that life exists somewhere.

Venus is often described as Earth's twin due to its similar size and structure. But their conditions couldn't be further apart, as astronomers believe it would be impossible for humans to exist on Venus. Positioned 67 million miles from the Sun, Venus is the hottest planet in our solar system, suffering temperatures that can even melt lead. Its atmosphere also adds to the uninhabitable situation.

Despite this, scientists have long debated whether Venus' clouds may host microbial（微生物的） life forms that can survive. Many scientists think that photosynthesis（光合作用） is possible on the planet's surface as Venus receives enough solar energy to pass through its thick clouds.

However, Professor Dominic Papineau, a biologist at the University College of London, believes Dr Thaller's views are "difficult to realistically assume". He explained, "For life-related chemical reactions to take place, liquid water is necessary. Hence, to find extraterrestrial life, we need to find liquid water, and to find extraterrestrial fossils requires looking for special rocks that were associated with liquid water in the past."

This makes life on Venus today difficult to realistically assume, because its surface is too hot, although Venus might have had liquid water in its past. Even still, both Professor Papineau and Dr Thaller agree that the icy moons of our solar system could also be sites of potential microbial life. NASA suggests there are 290 "traditional moons" in our solar system—excluding 462 smaller minor planets.

When Leone Meyer discovered in 2012 that a painting Nazis had stolen from her father was in the collection of an American museum, her first response was to demand its return.

But Ms. Meyer, who is 80 in Paris, and the Fred Jones Jr. Museum of Art at the University of Oklahoma, struck an agreement in 2016: The 1886 painting, Shepherdess Bringing In Sheep, would be displayed at a museum in France for five years, and then would rotate (轮转) every three years between the university and one or more French institutions of Ms. Mever's choosing.

In 2018, Ms. Meyer, tried to donate it to the Musee d'Orsay, where it has been on display since 2017, for its permanent collection. But the museum refused, telling Ms. Mever it did not want to assume the cost and risk of transporting the painting to America every three years, which would have been required under the terms of the settlement. Any other French institution she offered it to would probably do the same. Ms. Meyer is now seeking to prevent it from being displayed at the

University of Oklahoma, where it is scheduled to return in July. She has also filed a lawsuit in France seeking permanent ownership,

But the university disagrees that the French museum's refusal to accept the work is grounds for making the original deal have no legal effect. Ms. Meyer" now seeks to break" a settlement that "was a first-of-its-kind U. S. -France international art sharing agreement," according to the university.

The university has acknowledged that the painting was stolen by the Nazis from Ms. Meyer's father, but said in the previous court hearings that it did not want to return the work because of procedural rules and other laws. It also produced evidence that the previous owners, the Weitzenhoffer family, who donated it to the university in 2000, having bought it at a New York gallery, had acted in good faith.

The wires, screens and batteries that make up our devices—not to mention the plastic, metal and other materials that package them—are filling up landfills. Some e-waste is relatively large: old phones and air conditioners, for instance. Other e-waste is more hidden, such as electronic single-use medical diagnostic kits, environmental sensors, and smart labels that contain one-off batteries and other equipment.

"It's these small batteries that are big problems," says public health scientist Dele Ogunseitan, who was not involved in developing the battery. "Nobody really pays attention to where they end up."

Researchers at the Cellulose & Wood Materials Laboratory at the Swiss Federal Laboratories for Materials Science and Technology (Empa) are working to address this problem. Their new paper in Scientific Reports describes a paper battery developed from environmentally friendly materials that could eventually present a sustainable alternative to the more harmful batteries common in low-power devices.

The paper battery has the same key components as standard batteries but packages them differently. Like a typical chemical battery, it has—a positively charged side called a cathode (正极), a negatively charged side called an anode (负极), and a conductive material called an electrolyte (电解质)between the two. A traditional battery's components are packaged in plastic and metal; in the new battery, the anode and cathode are inks printed onto the front and back of a piece of paper. That paper is filled with salt, which dissolves (溶解) when the paper is dampened with water. The resulting saltwater solution acts as the electrolyte.

When the paper is dry, the battery is shelf-stable. Add just a couple of drops of water, however, and the salt dissolves, allowing electrons to flow. Once the paper is dampened, the battery becomes active within 20 seconds. The new battery's operating performance declines as the paper dries. When the scientists rewet the paper during testing, the battery regained functionality and lasted an hour before beginning to dry out again.