SEATTLE — Luke Skywalker’s home planet in Star Wars is the stuff of science fiction. But Tatooine-like planets in orbit around pairs of stars might be our best bet in the search for habitable planets beyond our solar system.

Many stars in the universe come in pairs. And lots of those should have planets orbiting them (SN: 10/25/21). That means there could be many more planets orbiting around binaries than around solitary stars like ours. But until now, no one had a clear idea about whether those planets’ environments could be conducive to life. New computer simulations suggest that, in many cases, life could imitate art.
Earthlike planets orbiting some configurations of binary stars can stay in stable orbits for at least a billion years, researchers reported January 11 at the American Astronomical Society meeting. That sort of stability, the researchers propose, would be enough to potentially allow life to develop, provided the planets aren’t too hot or cold.

Of the planets that stuck around, about 15 percent stayed in their habitable zone — a temperate region around their stars where water could stay liquid — most or even all of the time.

The researchers ran simulations of 4,000 configurations of binary stars, each with an Earthlike planet in orbit around them. The team varied things like the relative masses of the stars, the sizes and shapes of the stars’ orbits around each other, and the size of the planet’s orbit around the binary pair.

The scientists then tracked the motion of the planets for up to a billion years of simulated time to see if the planets would stay in orbit over the sorts of timescales that might allow life to emerge.

A planet orbiting binary stars can get kicked out of the star system due to complicated interactions between the planet and stars. In the new study, the researchers found that, for planets with large orbits around star pairs, only about 1 out of 8 were kicked out of the system. The rest were stable enough to continue to orbit for the full billion years. About 1 in 10 settled in their habitable zones and stayed there.

Of the 4,000 planets that the team simulated, roughly 500 maintained stable orbits that kept them in their habitable zones at least 80 percent of the time.

“The habitable zone . . . as I’ve characterized it so far, spans from freezing to boiling,” said Michael Pedowitz, an undergraduate student at the College of New Jersey in Ewing who presented the research. Their definition is overly strict, he said, because they chose to model Earthlike planets without atmospheres or oceans. That’s simpler to simulate, but it also allows temperatures to fluctuate wildly on a planet as it orbits.
“An atmosphere and oceans would smooth over temperature variations fairly well,” says study coauthor Mariah MacDonald, an astrobiologist also at the College of New Jersey. An abundance of air and water would potentially allow a planet to maintain habitable conditions, even if it spent more of its time outside of the nominal habitable zone around a binary star system.

The number of potentially habitable planets “will increase once we add atmospheres,” MacDonald says, “but I can’t yet say by how much.”

She and Pedowitz hope to build more sophisticated models in the coming months, as well as extend their simulations beyond a billion years and include changes in the stars that can affect conditions in a solar system as it ages.

The possibility of stable and habitable planets in binary star systems is a timely issue says Penn State astrophysicist Jason Wright, who was not involved in the study.

“At the time Star Wars came out,” he says, “we didn’t know of any planets outside the solar system, and wouldn’t for 15 years. Now we know that there are many and that they orbit these binary stars.”

These simulations of planets orbiting binaries could serve as a guide for future experiments, Wright says. “This is an under-explored population of planets. There’s no reason we can’t go after them, and studies like this are presumably showing us that it’s worthwhile to try.”

Supercooled water is two of a kind, a new study shows.

Scientists have long suspected that water at subfreezing temperatures comes in two distinct varieties: a high-density liquid that appears at very high pressures and a low-density liquid at lower pressures. Now, ultrafast measurements have caught water morphing from one type of liquid to the other, confirming that hunch. The discovery, reported in the Nov. 20 Science, could help explain some of water’s quirks.

The experiment “adds more and more evidence to the idea that water really is two components … and that that is the reason that underlies why water is so weird,” says physicist Greg Kimmel of Pacific Northwest National Laboratory in Richland, Wash., who was not involved in the study.

When free from impurities, water can remain liquid below its typical freezing point of zero degrees Celsius, forming what’s called a supercooled liquid. But the dual nature of supercooled water was expected to appear in a temperature realm so difficult to study that it’s been dubbed “no-man’s-land.” Below around –40° C, water remains liquid for mere instants before it crystallizes into ice. Making the task even more daunting, the high-density phase appears only at very high pressures. Still, “people have dreamt about how to do an experiment,” says Anders Nilsson of Stockholm University.
Thanks to speedy experimental maneuvers, Nilsson and colleagues have infiltrated that no-man’s-land by monitoring water’s properties on a scale of nanoseconds. “This is one of the major accomplishments of this paper,” says computational chemist Gül Zerze of Princeton University. “I’m impressed with their work.”

The scientists started by creating a type of high-density ice. Then, a pulse from an infrared laser heated the ice, forming liquid water under high pressure. That water then expanded, and the pressure rapidly dropped. Meanwhile, the researchers used an X-ray laser to investigate how the structure of the water changed, based on how the X-rays scattered. As the pressure decreased, the water transitioned from a high-density to low-density fluid before crystallizing into ice.

Previous studies have used ultrafast techniques to find hints of water’s two-faced demeanor, but those have been done mainly at atmospheric pressure (SN: 9/28/20). In the new work, the water was observed at about 3,000 times atmospheric pressure and –68° C. “It’s the first time we have real experimental data at these pressures and temperatures,” says physicist Loni Kringle of Pacific Northwest National Laboratory, who was not involved with the experiment.

The result could indicate that supercooled water has a “critical point” — a certain pressure and temperature at which two distinct phases merge into one. In the future, Nilsson hopes to pinpoint that spot.

Such a critical point could explain why water is an oddball liquid. For most liquids, cooling makes them become denser and more difficult to compress. Water gets denser as it is cooled to 4° C, but becomes less dense as it is cooled further. Likewise, its compressibility increases as it’s cooled.

If supercooled water has a critical point, that could indicate that the water experienced in daily life is strange because, under typical pressures and temperatures, it is a supercritical liquid — a weird state that occurs beyond a critical point. Such a liquid would not be the high-density or low-density form, but would consist of some regions with a high-density arrangement of water molecules and other pockets of low density. The relative amounts of those two structures, which result from different arrangements of hydrogen bonds between the molecules, would change as the temperature changes, explaining why water behaves strangely as it is cooled.

So despite the fact that the experiment involved extreme pressures and temperatures, Nilsson says, “it influences water in our ordinary life.”

2022 was the year many people decided the coronavirus pandemic had ended.

President Joe Biden said as much in an interview with 60 Minutes in September. “The pandemic is over,” he said while strolling around the Detroit Auto Show. “We still have a problem with COVID. We’re still doing a lot of work on it. But the pandemic is over.”

His evidence? “No one’s wearing masks. Everybody seems to be in pretty good shape.”

But the week Biden’s remarks aired, about 360 people were still dying each day from COVID-19 in the United States. Globally, about 10,000 deaths were recorded every week. That’s “10,000 too many, when most of these deaths could be prevented,” the World Health Organization Director-General Tedros Adhanom Ghebreyesus said in a news briefing at the time. Then, of course, there are the millions who are still dealing with lingering symptoms long after an infection.
Those staggering numbers have stopped alarming people, maybe because those stats came on the heels of two years of mind-boggling death counts (SN Online: 5/18/22). Indifference to the mounting death toll may reflect pandemic fatigue that settled deep within the public psyche, leaving many feeling over and done with safety precautions.

“We didn’t warn people about fatigue,” says Theresa Chapple-McGruder, an epidemiologist in the Chicago area. “We didn’t warn people about the fact that pandemics can last long and that we still need people to be willing to care about yourselves, your neighbors, your community.”

Public health agencies around the world, including in Singapore and the United Kingdom, reinforced the idea that we could “return to normal” by learning to “live with COVID.” The U.S. Centers for Disease Control and Prevention’s guidelines raised the threshold for case counts that would trigger masking (SN Online: 3/3/22). The agency also shortened suggested isolation times for infected people to five days, even though most people still test positive for the virus and are potentially infectious to others for several days longer (SN Online: 8/19/22).

The shifting guidelines bred confusion and put the onus for deciding when to mask, test and stay home on individuals. In essence, the strategy shifted from public health — protecting your community — to individual health — protecting yourself.
Doing your part can be exhausting, says Eric Kennedy, a sociologist specializing in disaster management at York University in Toronto. “Public health is saying, ‘Hey, you have to make the right choices every single moment of your life.’ Of course, people are going to get tired with that.”

Doing the right thing — from getting vaccinated to wearing masks indoors — didn’t always feel like it paid off on a personal level. As good as the vaccines are at keeping people from becoming severely ill or dying of COVID-19, they were not as effective at protecting against infection. This year, many people who tried hard to make safe choices and had avoided COVID-19 got infected by wily omicron variants (SN Online: 4/22/22). People sometimes got reinfected — some more than once (SN: 7/16/22 & 7/30/22, p. 8).
Those infections may have contributed to a sense of futility. “Like, ‘I did my best. And even with all of that work, I still got it. So why should I try?’ ” says Kennedy, head of a Canadian project monitoring the sociological effects of the COVID-19 pandemic.

Getting vaccinated, masking and getting drugs or antibody treatments can reduce the severity of infection and may cut the chances of infecting others. “We should have been talking about this as a community health issue and not a personal health issue,” Chapple-McGruder says. “We also don’t talk about the fact that our uptake [of these tools] is nowhere near what we need” to avoid the hundreds of daily deaths.

A lack of data about how widely the coronavirus is still circulating makes it difficult to say whether the pandemic is ending. In the United States, the influx of home tests was “a blessing and a curse,” says Beth Blauer, data lead for the Johns Hopkins University Coronavirus Resource Center. The tests gave an instant readout that told people whether they were infected and should isolate. But because those results were rarely reported to public health officials, true numbers of cases became difficult to gauge, creating a big data gap (SN Online: 5/27/22).
The flow of COVID-19 data from many state and local agencies also slowed to a trickle. In October, even the CDC began reporting cases and deaths weekly instead of daily. Altogether, undercounting of the coronavirus’s reach became worse than ever.

“We’re being told, ‘it’s up to you now to decide what to do,’ ” Blauer says, “but the data is not in place to be able to inform real-time decision making.”

With COVID-19 fatigue so widespread, businesses, governments and other institutions have to find ways to step up and do their part, Kennedy says. For instance, requiring better ventilation and filtration in public buildings could clean up indoor air and reduce the chance of spreading many respiratory infections, along with COVID-19. That’s a behind-the-scenes intervention that individuals don’t have to waste mental energy worrying about, he says.

The bottom line: People may have stopped worrying about COVID-19, but the virus isn’t done with us yet. “We have spent two-and-a-half years in a long, dark tunnel, and we are just beginning to glimpse the light at the end of that tunnel. But it is still a long way off,” WHO’s Tedros said. “The tunnel is still dark, with many obstacles that could trip us up if we don’t take care.” If the virus makes a resurgence, will we see it coming and will we have the energy to combat it again?

A group at the National Bureau of Standards at B­oulder, Colo., now reports an extremely accurate [speed of light] measurement using the wavelength and frequency of a helium-neon laser.… The result gives the speed of light as 299,792.4562 kilometers per second.

Update
That 1972 experiment measured the two-way speed of light, or the average speed of photons that traveled from their source to a reflective surface and back. The result, which still holds up, helped scientists redefine the standard length of the meter (SN: 10/22/83, p. 263). But they weren’t done putting light through its paces. In the late 1990s and early 2000s, photons set a record for slowest measured speed of light at 17 meters per second and froze in their tracks for one-thousandth of a second (SN: 1/27/01, p. 52). For all that success, one major hurdle remains: directly testing the one-way speed of light. The measurement, which many scientists say is impossible to make, could resolve the long-standing question of whether the speed of light is uniform in all directions.

Some immune defenses of the brain may have their roots in the gut.

A new study in mice finds that immune cells are first trained in the gut to recognize and launch attacks on pathogens, and then migrate to the brain’s surface to protect it, researchers report online November 4 in Nature. These cells were also found in surgically removed parts of human brains.

Every minute, around 750 milliliters of blood flow through the brain, giving bacteria, viruses or other blood-borne pathogens an opportunity to infect the organ. For the most part, the invaders are kept out by three membrane layers, called the meninges, which wrap around the brain and spinal cord and act as a physical barrier. If a pathogen does manage to breach that barrier, the researchers say, the immune cells trained in the gut are ready to attack by producing a battalion of antibodies.

The most common route for a pathogen to end up in the bloodstream is from the gut. “So, it makes perfect sense for these [immune cells] to be educated, trained and selected to recognize things that are present in the gut,” says Menna Clatworthy, an immunologist at the University of Cambridge.

Clatworthy’s team found antibody-producing plasma cells in the leathery meninges, which lie between the brain and skull, in both mice and humans. These immune cells produced a class of antibodies called immunoglobulin A, or IgA.

These cells and antibodies are mainly found in the inner lining of the gut and lungs, so the scientists wondered if the cells on the brain had any link to the gut. It turned out that there was: Germ-free mice, which had no microbes in their guts, didn’t have any plasma cells in their meninges either. However, when bacteria from the poop of other mice and humans were transplanted into the mice’s intestines, their gut microbiomes were restored, and the plasma cells then appeared in the meninges.

“This was a powerful demonstration of how important the gut could be at determining what is found in the meninges,” Clatworthy says.

Researchers captured microscope images of an attack in the meninges of mice that was led by plasma cells that had likely been trained in the guts. When the team implanted a pathogenic fungus, commonly found in the intestine, into the mice’s bloodstream, the fungus attempted to enter the brain through the walls of blood vessels in the meninges. However, plasma cells in the membranes formed a mesh made of IgA antibodies around the pathogen, blocking its entry. The plasma cells are found along the blood vessels, Clatworthy says, where they can quickly launch an attack on pathogens.

“To my knowledge, this is the first time anyone has shown the presence of plasma cells in the meninges. The study has rewritten the paradigm of what we know about these plasma cells and how they play a critical role in keeping our brain healthy,” says Matthew Hepworth, an immunologist at the University of Manchester in England who was not involved with the study. More research is needed to classify how many of the plasma cells in the meninges come from the gut, he says.

The finding adds to growing evidence that gut microbes can play a role in brain diseases. A previous study, for instance, suggested that in mice, boosting a specific gut bacterium could help fight amyotrophic lateral sclerosis, or ALS, a fatal neurological disease that results in paralysis (SN: 7/22/19). And while the new study found the plasma cells in the brains of healthy mice, previous research has found other gut-trained cells in the brains of mice with multiple sclerosis, an autoimmune disease of the brain and the spinal cord.

For now, the researchers want to understand what cues plasma cells follow in the guts to know it is time for them to embark on a journey to the brain.

It’s official: 2020 now has the most named storms ever recorded in the Atlantic in a single year.

On November 9, a tropical disturbance brewing in the northeastern Atlantic Ocean gained enough strength to become a subtropical storm. With that, Theta became the year’s 29th named storm, topping the 28 that formed in 2005.

With maximum sustained winds near 110 kilometers per hour as of November 10, Theta is expected to churn over the open ocean for several days. It’s too early to predict Theta’s ultimate strength and trajectory, but forecasters with the National Oceanic and Atmospheric Administration say they expect the storm to weaken later in the week.

If so, like most of the storms this year, Theta likely won’t become a major hurricane. That track record might be the most surprising thing about this season — there’s been a record-breaking number of storms, but overall they’ve been relatively weak. Only five — Laura, Teddy, Delta, Epsilon and Eta — have become major hurricanes with winds topping 178 kilometers per hour, although only Laura and Eta made landfall near the peak of their strength as Category 4 storms.

Even so, the 2020 hurricane season started fast, with the first nine storms arriving earlier than ever before (SN: 9/7/20). And the season has turned out to be the most active since naming began in 1953, thanks to warmer-than-usual water in the Atlantic and the arrival of La Niña, a regularly-occurring period of cooling in the Pacific, which affects winds in the Atlantic and helps hurricanes form (SN: 9/21/19). If a swirling storm reaches wind speeds of 63 kilometers per hour, it gets a name from a list of 21 predetermined names. When that list runs out, the storm gets a Greek letter.

While the wind patterns and warm Atlantic water temperatures set the stage for the string of storms, it’s unclear if climate change is playing a role in the number of storms. As the climate warms, though, you would expect to see more of the destructive, high-category storms, says Kerry Emanuel, an atmospheric scientist at MIT. “And this year is not a poster child for that.” So far, no storm in 2020 has been stronger than a Category 4. The 2005 season had multiple Category 5 storms, including Hurricane Katrina (SN: 12/20/05).

There’s a lot amount of energy in the ocean and atmosphere this year, including the unusually warm water, says Emanuel. “The fuel supply could make a much stronger storm than we’ve seen,” says Emanuel, “so the question is: What prevents a lot of storms from living up to their potential?”
A major factor is wind shear, a change in the speed or direction of wind at different altitudes. Wind shear “doesn’t seem to have stopped a lot of storms from forming this year,” Emanuel says, “but it inhibits them from getting too intense.” Hurricanes can also create their own wind shear, so when multiple hurricanes form in close proximity, they can weaken each other, Emanuel says. And at times this year, several storms did occupy the Atlantic simultaneously — on September 14, five storms swirled at once.

It’s not clear if seeing hurricane season run into the Greek alphabet is a “new normal,” says Emanuel. The historical record, especially before the 1950s is spotty, he says, so it’s hard to put this year’s record-setting season into context. It’s possible that there were just as many storms before naming began in the ‘50s, but that only the big, destructive ones were recorded or noticed. Now, of course, forecasters have the technology to detect all of them, “so I wouldn’t get too bent out of shape about this season,” Emanuel says.

Some experts are hesitant to even use the term “new normal.”

“People talk about the ‘new normal,’ and I don’t think that is a good phrase,” says James Done, an atmospheric scientist at the National Center for Atmospheric Research in Boulder, Colo. “It implies some new stable state. We’re certainly not in a stable state — things are always changing.”