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Wednesday, December 8, 2021

Science Scene

 

Computers might run on infrared light

Computer engineers at the University of Utah have begun to build computers that can harness infrared light, the only part of the electromagnetic spectrum that has not yet been utilized for communication. The engineers expect that in another 10 years they will have built ultra-fast computers that don’t run on electricity.

Where electricity is conducted through metal wires, computer circuits built on light rely on fiber optic cables and devices called waveguides to split the light into different colors or “channels” of information.

The engineers designed perforated sheets of stainless steel foil that effectively directed the infrared radiation to transmit, spilt, bend or combine a signal. The pieces of foil were four inches long, one inch wide and 625 microns thick. A micron is approximately 6.25 times the width of a human hair. The perforations were rectangular holes only 500 microns across, or five human hairs.

Current computers run at gigahertz frequencies, which are billions of cycles per second, whereas a light computer would run at tetrahertz frequencies, which are trillions of cycles per second. They published their results in the Apr. 18 online issue of Optics Express.

(sciencedaily.com)

 

Asteroseismology – researchers “listen” to a star

Astronomers at the University of Toulouse, France, have used a new technique to understand how a star, named Iota Horologii, 56 million light-years away drifted away from the Hyades cluster. The findings have implications for theories of star and planet formation.

The technique, called asteroseismology, is similar to a technique geologists use to understand the earth’s inner structure by studying how the seismic waves of earthquakes run through the earth. The astronomers used the state-of-the-art 3.6 meter telescope at La Silla, Chile with a spectrograph mounted to it.

The astronomers took a series of observations on eight consecutive nights in November 2006 and the data showed that there were 25 different “notes” of sound coming from the star.

After analysis of the data, the researchers found that the star had a temperature 6150 K, a mass that is 1.25 times that of the sun, an age of 625 million years, and that it was approximately 50 percent more metal-rich than our Sun. (sciencecentric.com)

 

E. coli engineered to move toward pesticide

Escherichia coli have receptor proteins on the outer surface of its cell membrane that identify a chemical of interest and its concentration. The proteins then provide a signal to the bacterium’s flagellum to either move the bacterium toward or away from the chemical.

Researchers at Emory University in Atlanta, Georgia engineered E. coli to lack the gene responsible for movement. They then provided the movement gene in a strand of engineered RNA called a riboswitch. The riboswitch would only turn on in the presence of the pesticide atrazine. The result is that bacteria can move toward the pesticide on a Petri dish and metabolize it, degrading the pesticide into another form. (nature.com)

 

Grand Canyon older than previously thought

Using radiometrics, the process of measuring the rates of decay of radioactive isotopes from the canyon walls, the Grand Canyon was thought to be only 6 million years old. In March, researchers used a variation of radiometrics to analyze minerals in the roofs of caves in the canyon walls and dated the start of the canyon’s formation at 17 million years.

However, geologists from the California Institute of Technology, Pasadena recently dated the Grand Canyon at 65 million years, old enough that dinosaurs may have lived in and around it. The researchers developed a new technique that analyzes a mineral called apatite. Apatite contains small amounts of uranium and thorium, radioactive elements that release a type of helium when they decay.

Apatite, once buried deep beneath canyon’s surface, was gradually exposed by the eroding effects of the Colorado River. Samples of apatite taken from the bottom of the Grand Canyon turned out to be between 55 and 65 million years old. (sciencenow.sciencemag.org)

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