Martian dust is a major hurdle for human missions to Mars. Like Moon dust, its fine size and electrostatically charged nature allow it to stick to spacesuits, metal, and just about any other surface they come into contact with. Dust storms are also common on Mars, ranging from small whirlwinds that happen daily to global dust storms that occur once every 3 Martian years (~5.5 Earth years) and envelop the entire planet. Due to the low density of Mars' atmosphere, these storms don't generate much physical force.

The danger lies in how the dust plays havoc with instruments, machine parts, and astronaut health and safety. Given how well it adheres to surfaces, Apollo astronauts found that lunar dust accompanied them back into their landing modules, degrading mechanical joints and seals and causing respiratory problems. A recent study led by Washington University in St. Louis (WashU) highlights the need, using data from NASA's Perseverance rover, for sufficient astronaut training to prepare for the Martian environment.

In addition to its array of sensors, cameras, drilling equipment, and sample cache, Perseverance also carries small swatches of spacesuit material that are constantly exposed to Mars' atmosphere. Using data acquired by the rover's Planetary Instrument for X-ray Lithochemistry (PIXL), the team examined the swatches for signs of wear and tear. They also applied a method developed by VanBommel to estimate the size of each particle in the PIXL data, providing the first direct characterization of fine (≲2.5 µm) and ultrafine particles (≲0.1 µm).

Their analysis found that the swatches showed little visible wear after 1,645 Martian days (sols) of exposure, largely because the particles observed were much smoother than the jagged grains found on the Moon. In summary, the results showed that Martian dust may be less likely to be abrasive to equipment or harmful to astronaut health than lunar regolith. The PIXL data also allowed the team to analyze the chemical composition of the particles that had caked the swatches.

From this, the team confirmed the presence of perchlorates and other toxins, as well as high levels of sulfur, iron, and silica in the dust grains. In addition, Martian dust can be exceptionally fine, with some ultrafine particles measuring as little as 100 nanometers (nm) in diameter. On Earth, ultrafine particles typically come in the form of smoke and air pollution, which can cause significant health problems because they can sink deep into the lungs and enter the bloodstream. With Martian dust carrying perchlorates and other toxins, the health risk is magnified...

What if a robot could be squishy? Soft, flexible robots could be useful for a wide variety of applications, including artificial muscles and wearable devices—or really any application where a robot must be especially delicate.

This is what has fueled development of “soft actuators” that can flex like a bicep and have a fine-tuned sense of touch as in the human hand. Like your stereotypical robot, soft actuators convert energy—such as electricity, heat, or light—into mechanical motion, but they look nothing like the metal and wire constructs that the word “robot” most often evokes.

One variety of these soft robots, known as bioactuators, utilizes the functions of living cells to generate motion. These biological machines have attracted particular attention in recent years, and now a research team at Delft University of Technology in the Netherlands has developed a soft robotic arm colonized by algae on its surface, and when the microbes photosynthesize, the arm moves.

“We didn’t start with a specific application. Our goal has always been to bring the research of living materials to new levels,” Marie-Eve Aubin-Tam, who led the research, explained in a press release. “We wanted to explore what becomes possible when living cells are integrated into functional materials.” ...

Has AI tackled a problem in physics that has been open for more than half-a-century? It seems so. Brian Greene explains OpenAI’s claim that a dominant component of the Standard Model of Particle Physics – so called, Yang-Mills Gauge Theory – has now been proven mathematically sound.

For decades, physicists have used the equations of the Standard Model to make exquisitely precise predictions, borne out by a mountain of experimental results. But getting to these results has required intermediate steps of questionable mathematical rigor. OpenAI says its models have now filled in the missing math, finally placing years of calculations on a firm mathematical footing, and addressing half of a million-dollar Millennium Prize problem. Brian walks through what that proof covers, what still sits with the review committee, and why the other half of the million-dollar problem, the Mass Gap problem, remains open.

Exposure to toxic metals like cadmium has been associated with adverse pregnancy outcomes such as miscarriage, preterm birth and low birth weight. Because these effects are difficult and ethically challenging to study directly in pregnant women, how such exposures affect pregnancy has remained poorly understood.

The placenta-on-a-chip model developed by Dan Huh, J. Peter Skirkanich professor in bioengineering, and colleagues at Penn Engineering offers a way to investigate these questions using living human cells. In a study published in Nature Biomedical Engineering, the team led by Huh, together with collaborators at Princeton, Sogang University in Seoul, Korea, and Rutgers University, used the bioengineered model to examine how cadmium, a toxic metal found in food, drinking water and tobacco smoke, affects the placenta's ability to support a developing fetus.

The group's experiments revealed that cadmium can impair the placenta even at relatively low exposure levels that do not kill cells. The researchers also identified a protein that helps protect placental tissue, along with metabolic changes that could provide clues to exposure-related damage.

Recreating the maternal–fetal interface
In the placenta, maternal and fetal blood circulate in separate compartments and exchange nutrients and other substances across a thin layer of tissue. Huh and his collaborators developed a microfluidic device that recreates key features of this maternal–fetal interface.

The device is built with human placental cells isolated from donated placentas. On one side, a layer of these cells is exposed to flowing fluid that simulates maternal blood. On the other, a three-dimensional tissue structure contains a network of fetal blood vessels embedded in a hydrogel scaffold.

The model also incorporates oxygen conditions that more closely reflect those inside the placenta than conventional cell culture systems. Researchers can introduce additional cell types, including placental immune cells, to investigate more complex biological responses.

Huh's earlier placenta-on-a-chip research focused on how drugs cross the placental barrier.

"Our new work expands the original capabilities of the technology and allows us to emulate the human maternal–fetal interface with greater fidelity and study the effect of environmental toxins under more realistic conditions," says Huh. "We can now ask not only whether cadmium crosses the barrier but also how it affects the placenta's ability to perform its key physiological functions." ...

No other traveler has ever journeyed so far from home.

Voyager 1 is about to become the first human-made object to reach a distance of one light-day from Earth, or about 16 billion miles. ½

Like most cats, Cooper used to love climbing into cardboard boxes. But one day, a box full of foam packing peanuts caught this tabby by surprise. Her owner, Sean McGrath, soon heard a commotion coming from the box and pulled her out. Thanks to static electricity, foam pellets now clung to her fur from head to tail.

Cooper seemed stunned. “She just stood there, frozen,” says McGrath, 44, of St. John, Canada. He snapped a photo before brushing her off. That picture, taken 20 years ago, eventually found its way to Wikipedia. Cooper unwittingly came to embody static electricity. She has appeared in textbooks, college lectures and more — all to help explain this sticky science.

Static electricity is common in everyday life. It’s why rubbing a balloon on your head makes your hair cling to it. It’s why clothing fresh from the dryer can stick to your legs. It’s also behind the painful shock you sometimes get when you touch a doorknob.

But the science of static electricity is surprisingly mysterious.

We know it’s caused by an electric charge moving between objects when they touch. But how — exactly — does that happen? In most situations, “we really have no clue,” says Galien Grosjean. A physicist, he works at the Autonomous University of Barcelona in Spain. He’s one of a small, quirky group of scientists who are obsessed with static electricity. The crew includes physicists, engineers, chemists and materials scientists.

Each researcher in this group holds a piece of the static-electricity puzzle. But they’re finally putting some of the pieces together to make progress...

One of a human’s earliest developmental milestones is an understanding of object permanence. It generally takes less than a year for a baby to realize that when an adult hides their face behind their hands in a game of peek-a-boo, they don’t cease to exist. There’s more to the world around us than what we perceive.

This suggests — or at least, it suggested to Albert Einstein — that the world is “real,” in the sense that things in the world have properties that are intrinsically true no matter what anyone thinks. A red billiard ball is red, even in the dark, and even if no one is checking its color. The redness is a property belonging to the ball, not to some device measuring the ball, and not to the mind of some person operating the measuring device.

Yet quantum mechanics, a thoroughly validated theory of how the world works, seems to suggest otherwise. The theory’s math assigns redness to the billiard ball at the moment you measure it. Before then, the theory gives you only a set of probabilities telling you what color the ball might be. Key founders of quantum mechanics suggested that this math reflects the nature of reality — that in some sense, a single, objective reality doesn’t really exist.

In 1935, Einstein rebelled against this surreal reading of quantum theory, proposing one of the 20th century’s most famous thought experiments. But his rebellion was doomed. In 1964, the physicist John Stewart Bell showed with a thought experiment of his own that reality had to be stranger than Einstein assumed. Subsequent work would put Bell’s thought experiment to the test — and prove him right.

Then, 50 years after Bell, Matthew Pusey, at the time a graduate student at Imperial College London, took on what remained of Einstein’s notion of reality and — without originally intending to — delivered the killing blow.

The paradigm-shifting theorem became known as PBR, for Pusey and his academic accomplices, Jonathan Barrett and Terry Rudolph. Since the publication of PBR in 2012, many theorists have come to accept that it rules out our most commonsense understanding of reality.

“From the moment [PBR] came out, people knew it would be a landmark,” said Jacques Pienaar, a physicist now at the Federal University of Rio de Janeiro in Brazil.

At the time, Pienaar, like Pusey, had been walking in Einstein’s footsteps, dabbling in theories designed to show that objective reality exists and that quantum mechanics merely describes our incomplete knowledge of it. But when the PBR theorem appeared, Pienaar remembers thinking, “That’s it. The program’s dead.”

This is the story of how Einstein, Bell, and finally Pusey and his collaborators killed reality as we know it. In three theorems, they proved that quantum mechanics is incompatible with the world we perceive. And since experiment after experiment — including a recent realization of PBR — has established that quantum mechanics is the law of the land, something about reality has to go.

The question that remains is: How much do we have to give up? ...

NASA's Nancy Grace Roman Space Telescope is nearing its final destination more than 1 million miles (1.6 million kilometers) from Earth, where it will soon scour the universe for a host of cosmological treasures, including an estimated 100,000 new alien worlds.

But even before its mission truly begins, recent developments suggest the state-of-the-art spacecraft could take better images than — and remain operational for more than twice as long as — initially expected, further delighting already-excited astronomers.

"It is fantastic to learn that Roman is not just reaching its design goals but exceeding them," Eamonn Kerins, an astronomer at the University of Manchester in the U.K. who will help lead one of Roman's major surveys, told Live Science.

NASA's Nancy Grace Roman Space Telescope is nearing its final destination more than 1 million miles (1.6 million kilometers) from Earth, where it will soon scour the universe for a host of cosmological treasures, including an estimated 100,000 new alien worlds.

But even before its mission truly begins, recent developments suggest the state-of-the-art spacecraft could take better images than — and remain operational for more than twice as long as — initially expected, further delighting already-excited astronomers...