New research on Tunguska finds such events happen less often than we thought

New research on Tunguska finds such events happen less often than we thought

Enlarge / The famed Tunguska event of 1908 scorched a five-mile swath of trees and caused many to fall away from the center of the blast in a distinct radial pattern. (credit: Photo12/Universal Images Group via Getty Image)

Last month marked the 111th anniversary of the Tunguska event, a blast that flattened trees across half a million acres of Siberian forest on June 20, 1908. Scientists have been puzzling over the details ever since. We now have fresh evidence about what transpired back then, in the form of new data gleaned from a well-documented rare meteor burst near Chelyabinsk, Russia, in February 2013. That data shores up the hypothesis that the Tunguska event was most likely due to an asteroid impact. The findings are described in a series of scholarly papers commemorating the event, published in a special July 15 issue of the journal Icarus.

Seismometers all over

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Alternative theory of gravity makes a nearly testable prediction

Alternative theory of gravity makes a nearly testable prediction

Enlarge / Galaxy clusters generated by the Universe simulator IllustrisTNG. (credit: TNG Collaboration)

From our current perspective, the Universe seems to be dominated by two things we find frustratingly difficult to understand. One of these is dark matter, which describes the fact that everything from galaxies on up behaves as if it has more mass than we can detect. While that has spawned extensive searches for particles that could account for the visual discrepancy, it’s also triggered the development of alternative theories of gravity, ones that can replace relativity while accounting for the discrepancies in apparent mass.

So far, these proposals have fallen well short of replacing general relativity. And they say nothing about the other big mystery, dark energy, which appears to be accelerating the expansion of the Universe. Instead, researchers have developed an entirely separate class of theories that could modify gravity in a way that eliminates

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No more lumps: Let physics be your guide to making the perfect crepe

No more lumps: Let physics be your guide to making the perfect crepe

Enlarge / Batter must be distributed evenly to get uniform thickness in a perfect crepe. (credit: Mark Boster/Los Angeles Times/Getty Images)

Order a crepe from a professional vendor and they’ll likely cook it on a blade, a flat heated surface that distributes the batter evenly to get just the right consistency in the final crepe: uniform thickness with no unsightly lumps. But home cooks typically make crepes in a frying pan, which can make the process a wee bit trickier.

Still, no worries, all you home-cooking crepe lovers—physics has come to the rescue. According to the latest experiment results of two scientists, the trick is all in the wrist. They described their research in a recent paper published in Physical Review Fluids.

It all started when co-author Mathieu Sellier of the University of Canterbury in New Zealand expressed frustration to his wife that he could never get his

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Amino acids make beautiful music to design novel protein structures

Amino acids make beautiful music to design novel protein structures

There’s an app for that: Android users can now create their own bio-based musical compositions.

Nearly seven years ago, MIT scientists mapped the molecular structure of proteins in spider silk threads onto musical theory to produce the “sound” of silk in hopes of establishing a radical new way to create designer proteins. That work even inspired a sonification art exhibit, “Spider’s Canvas,” in Tokyo last fall. Artist Tomas Saraceno created an interactive instrument inspired by the web of a Cyrotophora citricola spider, with each strand in the “web” tuned to a different note.

Now MIT materials engineer Markus Buehler and his colleagues are back with an even more advanced system of making music out of a protein structure—and then converting it back to create novel proteins never before seen in nature. The team also developed a free app for the Android smartphone, called the Amino Acid Synthesizer, so users

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We’re one step closer to atomic radio

We’re one step closer to atomic radio

Enlarge / Physicist C.J. Holloway in his atomic recording studio at the National Institute of Standards and Technology in Maryland. (credit: J. Burras/NIST)

Scientists at the National Institute for Standards and Technology in Gaithersburg, Maryland, have brought us one step closer to “atomic radio” by using an atom-based receiver to make a stereo recording of music streamed into the laboratory—namely, Queen’s “Under Pressure.” They described their work in a new paper in AIP Advances.

So-called “Rydberg atoms” are atoms that are in an especially excited state well above their ground (lowest-energy) state. This makes them extra-sensitive to passing electric fields, like the alternating fields of radio waves. All you need is a means of detecting those interactions to turn them into quantum sensors—like a laser. That means, in principle, that Rydberg atoms could receive and play back radio signals.

This isn’t the first time Rydberg

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Physics indicates some of Earth’s earliest animals helped each other feed

Physics indicates some of Earth’s earliest animals helped each other feed

Enlarge / The result of a fluid mechanics simulation with multiple Erniettas. (credit: Dave Mazierski)

What drove the evolution of the earliest animal life? In modern animals, it’s easy to infer a lot about an organism’s lifestyle based on its anatomy. Even back in the Cambrian, with its large collection of bizarre looking creatures, these inferences are possible. Anomalocaris may have had a freakish, disk-shaped mouth, but it clearly was a mouth.

Go back to Earth’s earliest animals in the Ediacaran, however, and things get much, much harder. There’s only one species known so far that appears to have the right body plan to act as a predator of sorts. Beyond that, it’s all a collection of soft-looking fronds and segments that are difficult to ascribe any obvious function to. Faced with a lot of questions without obvious answers, biologists turned to an unlikely source of help: physicists and

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Two new papers explore the complicated physics behind bubbles and foams

Two new papers explore the complicated physics behind bubbles and foams

Enlarge / The complex physics of bubbles and foams have fascinated scientists for centuries. (credit: Ian Kington/AFP/Getty Images)

Human beings derive intense pleasure from bubbles and all kinds of foamy products, and scientists have long found them equally fascinating, given the complicated underlying physics. Most recently, a group of Japanese researchers published a paper in Scientific Reports describing two distinct mechanisms by which simple foams collapse. And in a new paper in the Proceedings of the National Academy of Sciences, physicists at MIT and Princeton University demonstrated how to develop spherical bubbles uniformly by confining them in a narrow tube.

Individual bubbles typically form a sphere, because that’s the shape with the minimum surface area for any volume and hence is the most energy efficient. Back in the 19th century, Lord Kelvin proposed a bizarre soccer-ball shape called a tetrakaidecahedron (Greek for “fourteen faces” and sometimes translated “tetradecahedron”), with

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Scientists found these old photographs contain metallic nanoparticles

Scientists found these old photographs contain metallic nanoparticles

Enlarge / The earliest reliably dated photograph of people, taken by Louis Daguerre one spring morning in 1838. (credit: Public domain)

Daguerreotypes are one of the earliest forms of photography, producing images on silver plates that look subtly different, depending on viewing angle. For instance they can appear positive or negative, or the colors can shift from bluish to brownish-red tones. Now an interdisciplinary team of scientists has discovered that these unusual optical effects are due to the presence of metallic nanoparticles in the plates. They described their findings in a new paper in the Proceedings of the National Academy of Sciences.

Co-author Alejandro Manjavacas—now at the University of New Mexico in Albuquerque—was a postdoc at Rice University, which boasts one of the top nanophotonics research groups in the US. That’s where he met his co-author, Andrea Schlather, who ended up in the scientific research department at the Metropolitan

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Rat brains provide even more evidence our brains operate near tipping point

Rat brains provide even more evidence our brains operate near tipping point

Enlarge / A real human brain suspended in liquid within a human silhouette carved into acrylic, on display at the Bristol Science Centre in England. New research finds more evidence that the brain operates near a critical point. (credit: Ben Birchall/PA Images/Getty Images)

The human brain doesn’t seem like it would have much in common with how water freezes into ice or heats up into a gas. But over the last decade, evidence has been mounting that the brain as a system functions much like water approaching the critical point of a phase transition. Now a team of Brazilian scientists has found additional evidence in rat brains that this might indeed be the case. The team described its findings in a recent paper in Physical Review Letters.

The notion of so-called “self-organized criticality” dates back to a landmark paper in 1987, when the late Danish physicist

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Researchers balance Casimir effects, make tiny hoverboard

Researchers balance Casimir effects, make tiny hoverboard

Enlarge (credit: Wikimedia Commons)

Empty space isn’t actually empty. Even if you somehow managed to suck every single atom out of it, the Universe is filled with various fields that dictate the behavior of particles and forces. These fields even create pairs of “virtual particles” that pop into existence briefly before annihilating each other.

This counterintuitive view of the nature of the Universe is an outgrowth of quantum field theory, but it was difficult to figure out any obvious consequences. That changed in 1948, when Dutch physicist Hendrik Casimir figured out a specific situation where the contents of empty space matter. Now called the Casimir effect, it creates a tiny force when two conductive metal plates are placed in close proximity.

In a new paper published in today’s edition of Science, researchers show that the Casimir effect can also be repulsive and use the balance between attractive and

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