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An ultramassive black hole is a black hole that has a mass of more than 10 billion times the mass of the sun. Black holes are regions of space where gravity is so strong that nothing, not even light, can escape. They are usually formed when massive stars collapse at the end of their life cycle.

Ultramassive black holes are rare and elusive, and their origins are unclear. Some scientists believe they were formed from the extreme merger of massive galaxies billions of years ago when the universe was still young.

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This finding, published in Science, was demonstrated by researchers from the Max Planck Institute of Animal Behavior, the Cluster of Excellence Center for the Advanced Study of Collective Behavior at the University of Konstanz, Germany, Tel Aviv University, and the Hebrew University of Jerusalem, Israel.

Would you be able to instantly recognize your location and find your way home from any random point within a three-kilometer radius, in complete darkness, with only a flashlight to guide you?

Echolocating bats face a similar challenge, with a local and directed beam of sound—their —to guide their way. Bats have long been known for their use of echolocation to avoid obstacles and orient themselves.

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Why are there atomic clocks but no nuclear clocks? After all, an atom’s nucleus is typically surrounded by many electrons, so in principle it should be less susceptible to outside noise (in the form of light). A nucleus, for high-atomic number atoms, contains more particles than does the element’s electrons. It holds nearly the entire mass of the atom while taking up only about 1/100,000th of the atom’s space. While the first atomic clock was invented in 1949, no nuclear clock has yet been feasible.

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A U.S. Naval Research Laboratory (NRL) multi-disciplinary team developed a new paradigm for the control of quantum emitters, providing a new method for modulating and encoding quantum photonic information on a single photon light stream.

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To effectively adapt to change, living organisms rely on their ability to rapidly detect and process sensory information in their surroundings. The sensory information available at a given time continuously changes, which means that it can typically only be observed partially and for a limited amount of time.

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A new model of liquid sprays reveals the mechanisms behind droplet formation—providing important information for eventually controlling the droplet sizes in, for example, home cleaning sprays.

Spraying a cleaning product on a kitchen counter may be a mundane task, but it embodies a wide-reaching environmental problem. In atomized sprays like these, the largest droplets land on the surface as desired, while the smallest ones drift away and evaporate, wasting liquid and contaminating the surroundings. As Isaac Jackiw of the University of Alberta, Canada, says, “If you have an intuitive understanding of where the different sizes come from, then you can start to imagine specific targeted approaches for preventing unwanted sizes.” He and his colleagues have now developed a physics-based model that predicts the distribution of droplet size in sprays emitted from a nozzle. Jackiw presented the work at the Canadian Chemical Engineering Conference in Toronto this month.

In classical models of aerodynamic droplet breakup, airflow hits a liquid and causes it to explode into droplets. To explain the average droplet size, theorists have often focused on a single, dominant mechanism. But these methods have not been able to directly predict the distribution in droplet sizes, Jackiw says. His approach can estimate the size distribution by incorporating several different mechanisms, each of which contributes droplets in a particular size range.

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A “Little Earth Experiment” inside a giant magnet sheds light on so-far-unexplained flow patterns in Earth’s interior.

Earth’s inner core is a hot, solid ball—about 20% of Earth’s radius—made of an iron alloy. The planet’s outer core, beneath the rocky mantle, is a colder, liquid metal. Geophysics models explain that, since the movement of a liquid metal induces electrical currents, and currents induce a magnetic field, convection and rotation produce our planet’s magnetic fields. But these models typically neglect an important contribution: how Earth’s magnetic field influences the very flows that generate it. Alban Pothérat of Coventry University, UK, and collaborators have now developed a theory that accounts for such feedback and vetted it using a lab-based “Little Earth Experiment” [1]. Their results inform a model pinpointing processes that might explain the discrepancies between theoretical predictions and satellite observations of Earth, opening new perspectives on the study of geophysical flows.

Understanding flows in planetary interiors is a long-standing challenge. “If you don’t account for the fact that the magnetic field itself changes the flow, then you won’t get the right flow,” says Pothérat. Indeed, both satellite data from the European Space Agency’s Swarm mission and state-of-the-art numerical simulations indicate certain circulating core flows where liquid produced at the boundary of the inner core is fed into the outer core, moves upward toward the poles, and from there finally flows back inward (Fig. 1).

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