Putting the Right Spin on It

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Infinite-capacity wireless vortex beams carry 2.5 terabits per second

Actually, it’s not spin. It’s the other angular momentum, pork the orbital variety.

These twisted signals use orbital angular momentum (OAM) to cram much more data into a single stream. In current state-of-the-art transmission protocols (WiFi, LTE, COFDM), we only modulate the spin angular momentum (SAM) of radio waves, not the OAM. If you picture the Earth, SAM is our planet spinning on its axis, while OAM is our movement around the Sun. Basically, the breakthrough here is that researchers have created a wireless network protocol that uses both OAM and SAM.

I couldn’t get a mental image of how you’d do this, but I think that’s because I was thinking about individual photons, and I don’t see how to get a photonic orbital angular momentum state. But this is data transmission, which can be analog, or even of it’s digital a “one” is made up of a bunch of photons, i.e. it’s classical.

So I grabbed the paper I could (an earlier one that demonstrated the effect, and to which I had access). Here’s what the antenna looks like

The light being sent will have a different phase depending on what part of the antenna is transmitting it, which gives you the vortex. 3 GHz signals have a wavelength of 10 cm, so that’s probably gives you the scale of the depth of the slice in the parabolic dish.

This technique is likely to be used in the next few years to vastly increase the throughput of both wireless and fiber-optic networks.

I think this is overly optimistic. It’s going to take time to make this robust for data transmission and then you have to deploy the technology. And fiber-optics? I don’t see how this would work in a fiber (a less forgiving environment to good polarization, which is likely to cause problems here), but I also don’t see it as being necessary. I don’t think fiber is as clogged as the RF spectrum is, and you can always add more fiber if you need to.

This Just In: Bearing False Witness No Longer a Sin

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Apparently, anyway.

How American fundamentalist schools are using Nessie to disprove evolution

Jonny Scaramanga, 27, who went through the ACE programme as a child, but now campaigns against Christian fundamentalism, said the Nessie claim was presented as “evidence that evolution couldn’t have happened. The reason for that is they’re saying if Noah’s flood only happened 4000 years ago, which they believe literally happened, then possibly a sea monster survived.

“If it was millions of years ago then that would be ridiculous. That’s their logic. It’s a common thing among creationists to believe in sea monsters.”

Private religious schools, including the Eternity Christian Academy in Westlake, Louisiana, which follows the ACE curriculum, have already been cleared to receive the state voucher money transferred from public school funding, thanks to a bill pushed through by state Governor Bobby Jindal.

A Taste of Honey

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A Beekeeper’s Perspective on Risk

Here’s another lesson by analogy: No queen bee is under pressure for quarterly pollen and nectar targets. The hive is only beholden to the long term. Indeed, beehives appear to underperform at times because they could collect more. But they are not designed to maximize current returns; they are designed to prevent cycles of feast and famine (a death sentence in the natural world). They concentrate their foraging on the most lucrative patches but keep an exploratory force in the field that will ensure future revenue sources when the current ones run dry. This exploratory force (call it an R&D expenditure) increases as conditions worsen.

Interesting perspective. Quite the opposite of what many businesses are doing these days.

… And the Miss Conception Award Goes to …

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Misconceptions about science

MISCONCEPTION: Scientists’ observations directly tell them how things work (i.e., knowledge is “read off” nature, not built).

CORRECTION: Because science relies on observation and because the process of science is unfamiliar to many, it may seem as though scientists build knowledge directly through observation. Observation is critical in science, but scientists often make inferences about what those observations mean. Observations are part of a complex process that involves coming up with ideas about how the natural world works and seeing if observations back those explanations up. Learning about the inner workings of the natural world is less like reading a book and more like writing a non-fiction book — trying out different ideas, rephrasing, running drafts by other people, and modifying text in order to present the clearest and most accurate explanations for what we observe in the natural world.

Were We Vealed in the First Place?

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America Revealed: Pizza Delivery

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AMERICA REVEALED takes viewers on a journey high above the American landscape to reveal the country as never seen before. Join host Yul Kwon (Winner of “Survivor: Cook Islands”) to learn how this machine feeds nearly 300 million Americans every day. Discover engineering marvels created by putting nature to work, and consider the toll our insatiable appetites take on our health and environment. Embark with Kwon on a trip that begins with a pizza delivery route in New York City, then goes across the country to California’s Central Valley, where nearly 50 percent of America’s fruits, nuts and vegetables are grown, and into the heartland for an aerial look at our farmlands. Meet the men and women who keep us fed – everyone from industrial to urban farmers, crop-dusting pilots to long-distance bee truckers, modern-day cowboys to the pizza deliveryman.

I'm Also A Drachma Short

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June 19, 240 B.C.: The Earth Is Round, and It’s This Big

Eratosthenes knew that at noon on the day of the summer solstice, the sun was observed to be directly overhead at Syene (modern-day Aswan): You could see it from the bottom of a deep well, and a sundial cast no shadow. Yet, to the north at Alexandria, a sundial cast a shadow even at the solstice midday, because the sun was not directly overhead there. Therefore, the Earth must be round — already conventionally believed by the astronomers of his day.

What’s more, if one assumed the sun to be sufficiently far away to be casting parallel rays at Syene and Alexandria, it would be possible to figure out the Earth’s circumference.