Space Wombats and Penguin Poop: Spying on Animals from Orbit

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Penguin Spotting, and Other Cool Satellite Tricks

You’d be surprised what you can see from 300 miles up

For Smithsonian Air & Space Magazine:

At first glance the picture might be an abstract oil painting or, less artistically, poppy seeds scattered on cream cheese. The “cheese” in this case is a field of ice off the coast of Antarctica, and the black seeds are emperor penguins. The photo was taken from space, and is a good example of how satellite imagery is helping biologists study wildlife populations in new ways. No scientist needed to set foot near the penguin colony or fly an airplane overhead: High-resolution images from an orbiting QuickBird satellite were good enough to monitor the colony’s health over time.

“The advent of remote sensing allows us basically to see some of these areas that you physically cannot get to, no matter how hard you try,” says Michelle LaRue of the University of Minnesota. She and her colleagues use high-resolution images purchased from DigitalGlobe, Inc., one of a few private companies that license satellite imagery to governments and academic researchers. Other scientists use free satellite images from Landsat and other government-run programs. Although those tend to be lower in resolution, they demonstrate how remote sensing is important for the literal big picture: The huge areas of land surveyed by satellite make possible research that couldn’t be done otherwise. That’s true whether the location is (like Antarctica) hard to get to, in a conflict zone, heavily populated, or just too darn big.

[Read the rest at Smithsonian Air & Space Magazine…]


Swarming in time, synchronizing in space

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This article is a little different from the fare you’re used to getting from me: it’s for SIAM News, which is the glossy magazine for members of the Society for Industrial and Applied Mathematics. The audience for this magazine, in other words, is professional mathematicians and related researchers working in a wide variety of fields. In this case, I covered research by mathematicians looking at a type of system that occurs in biology and materials science. While the article contains equations, I wrote it to be understandable if you skim that part.

Self-organization in Space and Time

For SIAM News:

Self-organization is an important topic across scientific disciplines. Be it the spontaneous flocking of birds or dramatic phase transitions like superconductivity in materials, collective behavior without underlying intelligence occurs everywhere.

Many of these behaviors involve synchronization, or self-organization in time, such as activation in heart cells or the simultaneous blinking of certain firefly species. Others are aggregations, or self-organization in space, like swarming insects, flocking birds, or the alignment of electron spins in magnetic material.

Despite their conceptual similarity, self-organization in space and time have largely been treated separately. “I was curious about whether the two fields had been wedded, and it turns out they hadn’t, at least not fully,” Kevin O’Keeffe, a postdoctoral researcher at the Massachusetts Institute of Technology, said. “I knew all these tricks and mathematical tools from synchronization, and I was looking to cross-fertilize them into the swarming world.”

[Read the rest at SIAM News]

Designing space telescopes the size of a dinner plate

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Could Future Telescopes Do Without the Mirror?

Tomorrow’s Hubble might be the size of a dinner plate.

For Air & Space Magazine:

Today’s telescopes can see better and farther than ever, but they have become expensive: NASA’s Kepler spacecraft, which discovered planets orbiting far-away stars, and the Large Synoptic Survey Telescope nearing completion in Chile, for example, each cost about half a billion dollars.

Researchers at Lockheed Martin have a radical proposal: Build the observatory without the telescope—sort of. The idea, called Segmented Planar Imaging Detector for Electro-optical Reconnaissance, or SPIDER, begins with large arrays of silicon chips called photonic integrated circuits (PICs). Each chip in SPIDER takes a wide-open image, like a mirror with no focusing point. Then a computer combines the images, gradually eliminating the blurring, in a method called interferometry. By the time thousands of PICs are combined, the image should be as sharp as one produced by a large—and expensive—telescope mirror.

[Read the rest at Air & Space Magazine]

Why physicists hate time

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Wait a second: What came before the big bang?

Not everyone thinks the universe had a beginning.

This story originally appeared in the print edition of the September issue of Popular Science. This week, it appeared online with enhanced graphics. The text is by PopSci editor Rachel Feltman and me; the art is by Matei Apostolescu.

Cosmologists used to think the universe was totally timeless: no beginning, no end. That might sound mind-melting, but it’s easier on the scientific brain than figuring out what a set starting point would mean, let alone when it would be. So some physicists have cooked up alternative cosmological theories that make time’s role seem a little less important. The concepts are as trippy as those black-light posters you had in college.

[read the rest at Popular Science]

How physics and biology work together to understand cell organization

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Cells get organized

How researchers probe the physics of motion, communication and organization in cell networks, and how understanding these systems could help us tackle serious issues in medicine and biology

self-organized bacterial community

A colony of bacteria organize with each other under certain conditions to maximize nutrient intake. [Credit: Eshel Ben-Jacob]

From Physics World:

Consider this scenario: in your haste to grab the latest issue of Physics World, you scrape your hand on your postbox. It’s nothing severe, just a little scratch, but if your immune system is functioning as it should, your body will perform an amazing feat of microscopic organization. Your body assesses the level of damage and threat from infection, sending security cells to the site to hoover up intrusive bacteria and seal the wound. Within a few days you’d hardly know the scrape was ever there: your skin and blood vessels repair themselves.

Except of course there’s no mind behind this repair. Your brain isn’t required to heal a wound: there’s no local oversight from any intelligent agent, and the cells involved don’t think. Instead, cells interact with their neighbours, and a larger pattern emerges from those small-scale interactions. That’s the key to “self-organization”, whether it occurs in the human immune system, swarms of locusts, water molecules in a snowflake or electrons in a magnetic material.

For that reason, researchers studying biological self-organization draw heavily on physics. Some directly investigate the physical interactions between cells and their environments; others use theoretical models drawn or adapted from physics to understand emergent behaviours in biological systems. It’s an interdisciplinary field, involving physicists, computer scientists, biologists, mathematicians and medical doctors.

The rest of this story is in the print edition of Physics World, which you can subscribe to through membership in the Institute of Physics, which costs £15, €20, or $25 per year. You can join by clicking here. You can also get a nice mobile- and tablet-formatted version of the story using the Physics World app, available in the Google Play and iTunes stores. However, if you just want to read the rest of this article, Physics World has kindly allowed me to offer it to you as a PDF download, which looks exactly like the printed version!

The physics of dinosaurs!

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Computer model for the swing of a Stegosaurus tail-spike assembly, also known as a thagomizer from a classic Gary Larson cartoon. (Alas, we didn't get permission to reprint this cartoon.)

Computer model for the swing of a Stegosaurus tail-spike assembly, also known as a thagomizer from a classic Gary Larson cartoon. (Alas, we didn’t get permission to reprint this cartoon.)

Like many (most?) of us, I was a huge dinosaur fan as a kid. I read every horrible, outdated book I could get my hands on. I read Robert Bakker’s book The Dinosaur Heresies not long after it was published, with its often-wrong but very provocative reimagining of how dinosaurs lived, moved, and interacted with their environments. My primary scientific love was space, and so I pursued physics as a career, but I never completely forgot my dinosaur obsession. Now in the February 2017 issue of Physics World, I get to combine the two interests!

Deducing how dinosaurs moved

How did dinosaurs dash and their cousins the pterosaurs take flight? Physics-based modelling is helping to solve these mysteries of movement

For Physics World:

Jurassic Park and its sequels are best thought of as monster movies. But they do make dinosaurs look and act like real animals – which, of course, they were. For more than 100 million years, various groups of dinosaur were the largest predators and herbivores on the planet. There were many smaller species too, though we only know about a fraction of them, since fossils of them are rare, and we’re aware of many only through fragments.

Scientists have been able to answer the biggest scientific question posed by Jurassic Park in one of its most tense chase scenes: could a Tyrannosaurus rex outrun a Jeep? (Answer: no.) Knowing the top speed of an apex predator is vital as it tells us what sorts of prey it could catch. To better understand these creatures, scientists also want to know if a Stegosaurus’ fearsome spike-wielding tail could be used as a weapon, and what damage it could do. Another question is how pterosaurs (cousins of the dinosaurs) could evolve to become the largest flying animals.

Answering all of these questions involves understanding what forces and torques these creatures’ skeletons could withstand. [Read the rest at Physics World]

Seeing the invisible monster at the Milky Way center

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This is my second print magazine feature for Smithsonian Air & Space Magazine. The first was about gravitational waves, published not long before the LIGO detector found the first gravitational wave signals. The new piece is about the black hole at the center of our galaxy, published just a few months before…well, read the article to see why this is a good time to be writing about that particular black hole.

The First Sighting of a Black Hole

We know one lurks at the center of the Milky Way, but to these astronomers, seeing will be believing

For Smithsonian Air & Space Magazine:

he center of the galaxy doesn’t look like much, even if you’re lucky enough to live in a place where the night sky is sufficiently dark to see the bands of the Milky Way. In visible light, the stars between here and there blur together into a single brilliant source, like a bright beam hiding the lighthouse behind it.

But in other types of radiation—radio waves, infrared, X-rays—astronomers have detected the presence of an object with the mass of four million suns packed into a region smaller than our solar system: a supermassive black hole.

Astronomers call it Sagittarius A*, or Sgr A* (pronounced “sadge A star”) for short, because it’s located (from our point of view) in the Sagittarius constellation. Discovering the Milky Way’s black hole has helped cement the idea that the center of nearly every large galaxy harbors a supermassive black hole. But despite mounting evidence for black holes, we still haven’t seen one directly. [Read the rest at Smithsonian Air & Space Magazine]