Passengers use mobile stairs to exit and jet plane at night.
Enlarge / SAN ANTONIO, TX – FEBRUARY 17: American evacuees from the Diamond Princess cruise ship arrive at Joint Base San Antonio-Lackland on February 17, 2020, in San Antonio, Texas. The Diamond Princess cruise ship where the passengers were evacuated from, docked at the Japanese city of Yokohama, is believed to be the highest concentration of novel coronavirus cases outside of China, where the outbreak began.

Fourteen Americans tested positive for carrying the new coronavirus just as they began their return to the United States from Yokohama, Japan, where they had been trapped aboard the luxury cruise ship Diamond Princess in a quarantine that began February 3.

As of today, February 17, Japanese health officials have confirmed 454 cases of COVID-19 on the ship, including 99 cases reported since yesterday. The cluster is, by far, the largest of any COVID-19 flare ups outside of China, where the outbreak began and has caused the vast majority of infections and deaths.

The new cases in the returning Americans will nearly double the current number of COVID-19 cases in the US, bringing the total from the current 15 to 29.

Originally, no American cruise ship passengers infected with the new coronavirus were meant

Cartoon of the Sun, Earth, and Jupiter, with a diffuse collection of asteroids.

Despite its distance from the Sun, the asteroid belt will disintegrate as it expands.

We tend to view the bodies of the Solar System as creations of gravity, which pulled their parts together and holds them in place as they orbit. But as we saw with ideas about the formation of Arrokoth, there are lots of situations where gravity is essentially a constant for long periods of time. And given enough of that time, relatively small forces like friction from sparse gas clouds or pressure from the light of the Sun can add up and create dramatic changes. In fact, a remarkable number of these potential influences have been identified and simulated.

One of these has been named the YORP effect, for its developers, Yarkovsky, O’Keefe, Radzievskii, and Paddack. It describes how light can alter the rotational properties of orbiting bodies. In a recent edition of the Monthly Notices of the Royal Astronomical Society, Dimitri Veras and Daniel Scheeres decided to calculate what happens as the Sun ages, the intensity of its light increases dramatically, and the entire asteroid belt gets YORPed.

A (perhaps too) bright future

It’s pretty widely understood that, as the Sun ages, it will

Migrating geese fly in a V shape.

Even though it was, in most ways, identical to the present planet, the Earth still looked very different at the bottom of the last ice age 20,000 years ago. The globe was around 4°C cooler on average, and ice sheets covered large portions of the Northern Hemisphere, including Canada and Scandinavia. One thing you might wonder, given how much of the planet was barely habitable, is what migratory species did.

Given the loss of all that habitat to mile-thick glacial ice and a reduced winter-summer contrast courtesy of Earth’s orbital cycles, some researchers have hypothesized that bird migration wasn’t much of a thing then. Is it possible that bird species turned this behavior on and off through the ice ages?

A team led by Yale’s Marius Somveille tested this idea with a model of the factors controlling migratory behavior—and it predicts patterns surprisingly similar to the present day.

Migration on ice

Migration is essentially an annual investment, a bet that the incredible exertion of the journey will pay off with superior food resources and habitat. It’s what’s often called an “energetic optimization.” The model used in this study simulates everything as an energy cost-benefit calculation, taking into account the

Studying how ants organize division of labor within a colony can lend insight into how political polarization occurs in human society.
Enlarge / Studying how ants organize division of labor within a colony can lend insight into how political polarization occurs in human society.

Ants may be tiny critters with tiny brains, but these social insects are capable of collectively organizing themselves into a highly efficient community to ensure the colony survives. And it seems that the social dynamics of how division of labor emerges in an ant colony is similar to how political polarization develops in human social networks, according to a recent paper in the Journal of the Royal Society Interface.

“Our findings suggest that division of labor and political polarization—two social phenomena not typically considered together—may actually be driven by the same process,” said co-author Chris Tokita, a graduate student in ecology and evolutionary biology at Princeton University. “Division of labor is seen as a benefit to societies, while political polarization usually isn’t, but we found that the same dynamics could theoretically give rise to them both.”

Tokita and his adviser/co-author, Corina Tarnita, were collaborating with a group at Rockefeller University that was using camera tracking to study ants—specifically, how division of labor emerges in very small groups (between 12-16 ants). Their job was to devise a

Image of a car plugged into charging hardware.
Enlarge / The seemingly simple act of charging is getting increasingly complex.

Batteries tend to involve lots of trade-offs. You can have high capacity, but it means more weight and a slower charge. Or you can charge quickly and see the lifetime of your battery drop with each cycle. There are ways to optimize performance—figuring out the fastest charging you can do without cutting into the battery life—but that varies from product to product and requires extensive testing to identify.

But perhaps that testing is not so extensive, thanks to a new system described in the journal Nature. The system uses a combination of machine learning and Bayesian inference to rapidly zero in on the optimal charging pattern for any battery, cutting the amount of testing needed down considerably.

Not so fast

Fast charging is obviously useful for everything from phones to cars. But when a battery is subjected to fast charging, it doesn’t store its ions quite as efficiently. The overall capacity will go down, and there’s the potential for permanent damage, as some of the lithium ends up precipitating out and becoming unavailable for future use.

There are, however, ways of altering the charging profile to avoid this

A charter bus drives away from a cruise ship at night lit up like a Christmas Tree.
Enlarge / YOKOHAMA, JAPAN – FEBRUARY 19, 2020: A bus carrying passengers who will take the flight chartered by the government of the Hong Kong Special Administrative Region of the People’s Republic of China drives past the quarantined Diamond Princess cruise ship docked the Daikoku Pier.

On Wednesday, the initial 14-day quarantine aboard a coronavirus-stricken cruise ship docked in Yokohama, Japan, officially ended. But the grueling saga seems far from for over for the ship’s 3,711 passengers and crew.

As the quarantine time ran out, Japanese officials were still reporting dozens of new cases of COVID-19 aboard. As of Wednesday, the number of coronavirus infections linked to the ship total 621—by far the largest cluster of COVID-19 infections anywhere outside of China. The next-largest cluster outside of China is in Singapore, which has 84 confirmed cases.

Japanese health officials are facing international criticism for their handling of the quarantine on the ship, the Diamond Princess. The quarantine was intended to curb the spread of disease by keeping people aboard, isolated from each other and from the public on land. But as cases mounted over the two weeks, it became clear that the control efforts only enabled the new coronavirus