SciTech

Science Briefs: Slowing light to 112 mph, glacier belts on Mars, ordinary clay good for reducing CO2

Atoms coupled to a glass fiber: This system can slow light dramatically.
Atoms coupled to a glass fiber: This system can slow light dramatically. TU Wien illustration

Light can be dramatically slowed with glass fibers

Light is an extremely useful tool for quantum communication, but it has one major disadvantage: It usually travels at the speed of light and cannot be kept in place. A team of scientists at the Vienna University of Technology has demonstrated that this problem can be solved – and in the glass fiber networks we already use.

By coupling atoms to glass fibers, light was slowed down to 112 mph. The team even managed to bring the light to a complete stop and to retrieve it again later. This technology is an important prerequisite for a future glass fiber-based quantum-internet, in which quantum information can be teleported over great distances.

In a vacuum, the speed of light is always the same: approximately 670.6 million mph. When light is sent through a medium such as glass or water, it is slowed a little due to its interaction with the material. “In our system, this effect is extreme, because we are creating an exceedingly strong interaction between light and matter,” said professor Arno Rauschenbeutel. “The speed of light in our glass fiber is only 180 kilometers per hour. Any express train can top that.” tuwien.ac.at/en

Mars has huge water glaciers under surface dust

Mars has distinct polar ice caps, but Mars also has belts of glaciers at its central latitudes in both the southern and northern hemispheres. A thick layer of dust covers the glaciers, so they appear as surface of the ground.

Several satellites orbit Mars and on satellite images, researchers have been able to observe the shape of glaciers just below the surface. For a long time scientists did not know if the ice was made of frozen water (H2O), carbon dioxide (CO2) or mud. Using radar measurements from the NASA satellite, Mars Reconnaissance Orbiter, researchers have been able to determine that it is water ice.

How much ice is there? New studies at Denmark’s Niels Bohr Institute calculated the size of the glaciers and thus the amount of water in the glaciers. It is the equivalent of all of Mars being covered by more than one meter of ice.

The results are published in Geophysical Research Letter. nbi.ku.dk/english

Good for reducing greenhouse gas? Ordinary clay

Carbon capture will play a central role in helping nations of the world manage and reduce their greenhouse gas emissions. Many materials are being tested for capturing CO2, but researchers led by the Norwegian University of Science and Technology have found that ordinary clay can work just as effectively as more advanced materials.

“It is quite remarkable that clay can capture as much CO2 as other materials that are being investigated,” saide NTNU physicist Jon Otto Fossum.

Clay offers many benefits compared to other materials, particularly because other potential materials can be expensive, difficult to produce, toxic and not particularly environmentally friendly.

A possible practical future use of this discovery could be to include clays in CO2 filters for industrial-scale CO2 emissions reduction.

The results were published in Scientific Reports. ntnu.edu

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