Magnetic field

What a Purple Column of Light Named “Steve” Teaches Us About Our Potential

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What would you think if you were looking into the night sky and saw a purple column of light streak vertically in front of you? At first glance, it appears to be a phenomenon much like the Aurora Borealis or “Northern Lights,” according to Eric Donovan. He’s an associate professor of physics and astronomy at the University of Calgary. Prof. Donovan says it has the same arc shape as an aurora but the color is different. Auroras also usually go horizontally, while “Steve” as it’s been named, is vertical.

Canadians citizens discovered the phenomenon, which was recently verified by the European Space Agency (ESA). Prof. Donovan first came across it while viewing pictures on the Alberta Aurora Chasers’ Facebook page. “We have seen it from Hudson Bay all the way over to Alaska in our data, and so it’s like someone reached in from space and drew a line with a purple magic marker across the Earth,” Donovan said.

He and the ESA took the photos and information from the group’s page and cross-referenced it with data from ESA Swarm satellites. These monitor Earth’s magnetic field. Data from special cameras which watch the night sky was also used. Donovan and colleagues discovered that the phenomenon is 18 miles (25 km) wide, can last up to an hour, runs East to West, and isn’t often visible October…

Young eels use magnetic ‘sixth sense’ to navigate

juvenile European eel
EEL GPS Juvenile European eels may use Earth’s magnetic field to help them cross the Atlantic Ocean to reach freshwater rivers in Europe, including these seen in the U.K.’s Bristol Channel.

Earth’s magnetic field helps eels go with the flow.

The Gulf Stream fast-tracks young European eels from their birthplace in the Sargasso Sea to the European rivers where they grow up. Eels can sense changes in Earth’s magnetic field to find those highways in a featureless expanse of ocean — even if it means swimming away from their ultimate destination at first, researchers report in the April 13 Current Biology.

European eels (Anguilla anguilla) mate and lay eggs in the salty waters of the Sargasso Sea, a seaweed-rich region in the North Atlantic Ocean. But the fish spend most of their adult lives living in freshwater rivers and estuaries in Europe and North Africa.

Exactly how eels make their journey from seawater to freshwater has baffled scientists for more than a century, says Nathan Putman, a biologist with the National Oceanic and Atmospheric Administration in Miami.

The critters are hard to track. “They’re elusive,” says study coauthor Lewis Naisbett-Jones, a biologist now at the University of North Carolina at Chapel Hill. “They migrate at night and at depth. The only reason we know they spawn in the Sargasso Sea is because that’s where the smallest larvae have been collected.”

Some other marine animals, like sea turtles and salmon, tune in to subtle changes in Earth’s magnetic field to help them migrate long distances. To test whether eels might have the same ability, Putman and his colleagues placed young European eels in a 3,000-liter tank of saltwater surrounded by copper wires. Running electric current through the wires simulated the magnetic…

Disney Is Fulfilling One of Nikola Tesla’s Science Dreams

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You may not have known this, but The Walt Disney Company does much more than animated films and amusement parks. Its Disney Research arm, with divisions all over the world, has the mission to deliver all kinds of scientific and technological innovations. From video processing and robotics to behavioral sciences and materials research, Disney has it covered. Now, its researchers have brought us what we’ve all been waiting for (even without knowing it)—ubiquitous wireless power transfer or, in other words, electricity with no wires.

So, what is it going to take to have your phone charged without a power outlet and a charger? In layman’s terms, an apartment especially built for that purpose with a huge copper pole propped in the middle. In non-layman’s terms, the…

Magnetism helps black holes blow off gas

GRO J1655-40
WIND POWER A black hole steals gas from a normal star in this artist’s illustration of the binary star system GRO J1655-40. Most of the gas is pulled into an inward-spiraling disk (red) around the black hole, but winds driven by magnetic fields blow some gas away.

Black holes are a bit like babies when they eat: Some food goes in, and some gets flung back out into space. Astronomers now say they understand how these meals become so messy — and it’s a trait all black holes share, no matter their size.

Magnetic fields drive the turbulent winds that blow gas away from black holes, says Keigo Fukumura, an astrophysicist at James Madison University in Harrisonburg, Va. Using X-rays emitted from a relatively small black hole siphoning gas from a nearby star, Fukumura and colleagues traced the winds flowing from the disk of stellar debris swirling around the black hole. Modeling these winds showed that magnetism, not other means, got the gas moving in just the right way.

The model was previously used to explain the way winds flow around black holes millions of times the mass of the sun. Showing that the model now also works for a smaller stellar-mass black hole suggests that magnetism may drive winds in black holes of all sizes. These results, published online March 6 in Nature Astronomy, could give clues to how black holes consume and expel matter and also to why some galaxies stop forming stars.

Astronomers first proposed that magnetic fields powered the winds around black holes in the 1970s, but the idea has been controversial. Directly observing the winds is impossible. Their existence is inferred by a black hole’s X-ray spectrum — an inventory of light…