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Why do we live in a three-dimensional world?

Until something disrupts the rhythm of life (or you’re in the car with a five-year-old), most of us don’t stop to analyze why things are the way they are. We’re too busy navigating life to step back and ponder our reality. But let’s try it for a few minutes.

We live in a universe that physicists describe as having 3+1 dimensions–three dimensions in space and one in time. But was a 3D world a foregone conclusion? Could complex life have emerged and survived in a 2+1 (2D) world? This question is at the heart of a paper recently published in the journal Physical Review Research by James Scargill, a theorist at the University of California, Davis.

Some scientists have proposed that a universe with three spatial dimensions is the most stable kind of universe or has other physical advantages. This may be the case, but physicists haven’t been able to show it mathematically. Another way to approach this question is to add a bit of philosophy. The anthropic approach starts by recognizing tha…
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Turning “Smart Clothing” into Wearable Apparel

The future of clothing is electronic. Along with color and size, you’ll probably be able to choose clothes based on what they do—as determined by the sensors, indicators, and power sources embedded within them. Many researchers expect that such “smart clothing” will revolutionize at least some aspects of medicine and fashion. But in the age of leggings and stretch jeans, I have to ask: Will smart clothes be comfortable?

Thankfully, scientists are people too, and the comfort requirement hasn’t been lost on them. In a recent paper published in the journal Matter, a team of researchers from the University of Windsor (UWindsor) in Canada debuted a new approach to creating textiles that are smart and stretchable, soft, and wearable.

Electronics are traditionally rigid and hard. Fabrics are traditionally flexible and soft. Electronics have smooth metallic surface. Fabrics are composed of twisting, looping fibers that embrace empty space. One of the key challenges to achieving smart material…

New Spectra Comic: Super Special

Lucy and her Tesla Junior High classmates take a trip from Indiana to LIGO in Hanford, WA. Due to an unforeseen event, the laser goes offline right before the birth of a supernova. Follow spectra as she doubles up to undergo her biggest mission yet to collect gravitational waves from a rare exploding star.

Visit the Physics Central Website to view/download the spectra comic and to revisit past issues.

- Rose Villatoro

The Turbulent Relationship Between Sand Dunes

Fields of gently sloping sand dunes may look quiet and passive in photographs, but the serene patterns may be defined by turbulent negotiations. That’s the conclusion reached by scientists from the University of Cambridge in the UK who have spent the last few years studying how dunes interact with one another. The findings, published in the journal Physical Review Letters, offer new insight on a landscape that attracts tourists, threatens shipping lanes, buries highways, and colors the surface of Mars.

Sand dunes are formed by strong winds or flowing water. Desert dunes and underwater dunes have differences, of course, but their formation can be described by essentially the same physics–the interaction between particles of sand, fluid in motion, and the environment.

Dunes usually occur in vast fields that evolve and migrate over time. They’ve been known to bury forests and hide the remnants of entire cities. Dunes hold secrets of their own too. Secrets of structure, motion, and inter…

Why researchers are creating “human yarn” and turning it into textile

The phrase “human textiles” might conjure up thoughts of a creepy fashion show or disturbing line of bed linens, but that’s not where this story is going. These textiles represent a cutting-edge research effort to create medical products from biological components that are native to the human body.

From sutures that help wounds heal to grafts that bypass damaged blood vessels, textiles are invaluable and common medical tools. But there is a downside. Human immune systems often consider medical materials, especially those intended to be permanent, as foreign to the body. This can lead to inflammation and rejection.

A team of researchers led by Nicolas L’Heureux at the University of Bordeaux/INSERM is working on a new kind of medical textile that they hope will fly below the immune system’s radar. In tissue engineering research published earlier this month in the journal Acta Biomaterialia, the team introduced a completely biological human yarn that can be twisted, woven, braided, or kn…

Our Century-Old Notion of Wind Turbine Efficiency Is Going Through Some Turbulence

In 1920, a young German engineer named Albert Betz peered down at his calculations. Although interest in renewable energy was a long way from reaching its peak, he’d been exploring how wind turbines capture energy from the air. In the process, he had come up with a calculation for the greatest possible efficiency of any wind turbine: a shockingly tidy sixteen twenty-sevenths, or 59.3 percent. Since then, this number has been known as the Betz limit, serving as a virtually impossible goal for efficiency—until now.

“In order to make that calculation, [Betz] had to make some simplifying assumptions,” says John Dabiri, a professor of mechanical engineering at the California Institute of Technology. In particular, he chose to approximate all wind as perfectly steady. “Now, we know that’s untrue because the wind is turbulent,” says Dabiri. “If I’m standing on a wind farm, there will be gusts so the wind won’t be a fixed value.” Further complicating the situation, popular propeller-style tur…

The Identity Gap: How feelings of belonging push women out of physics

“You’re too pretty to be a physicist”

“Why are you in graduate school if you’re just going to leave once you have kids”?

“You don’t look like you study physics. I mean that as a compliment”

If you’re a female physicist, odds are you’ve heard something along the lines of this. Oof. In a recent discussion on twitter, women shared micro and microaggressions they’ve heard about their career paths, and unsurprisingly, the results weren’t great. It’s no secret that STEM is a male-dominated field, physics especially. You’ll see it right away when you walk into Physics 101 at any university. While other disciplines are seeing significant increases in female representation, physics has been the slowest discipline to show any progress. A new study from Physical Review PER shows that a lack of feedback and recognition contributes to a large gender gap in physics.

There are many reasons why this is the case. As a society, we’re not great at teaching physics. Traditional methods of teaching physi…