
Measuring local gravity
On the Earth’s surface, the standard figure for gravitational acceleration is known to be 9.8 meters per second squared, but the exact figure differs a little from place to place. Called local gravity, these variations in the Earth’s pull have very minimal effects on our day-to-day experience of the world, but they do matter in fields like volcanology and mining.
At Nanyang Technological University, Singapore, researchers are building a portable gravimeter to measure local gravity with pinpoint accuracy. Currently, geophysical surveys map the underground world through pressure waves, involving small but repeated pulses generated by explosives, hammers or dropped heavy objects.
While these waves are limited to mapping shallow areas, using quantum tech can offer longer range surveys and more detailed data on fault dynamics or fracturing of the Earth’s crust.
Because the strength of gravity changes depending on rock formations and crust density, high-precision quantum instruments give scientists a better idea of what’s happening beneath our feet.
In mineral prospecting, for example, small spikes in local gravity could signal the presence of oil deposits, diamonds or other rare minerals. A potential game-changer in monitoring seismic activity, this same technology may be used to detect slight shifts in the Earth’s crust due to tremors or the flow of magma underground before volcanic eruptions.
Asia’s finest detector for dust
In a first for Asia, researchers from the University of Science and Technology of China (USTC) have developed a quantum light detection and ranging (LiDAR) method for monitoring air pollution in the earth’s stratosphere, where the ozone layer is found.
The ozone layer filters out skin-damaging ultraviolet radiation from the sun, but air pollutants can deplete and cause holes in this layer, threatening the health of both humans and the environment.
By using quantum particles of light, the USTC team’s system measures wind velocity and calculates the distribution of air pollutants and levels of particulate matter (PM) or fine dust. About 70 times smaller than a strand of hair, PM can damage the heart and lungs when inhaled.
With its high-resolution detection capabilities, the LiDAR technology locates pollution sources and determines PM levels not just in China, but in neighboring countries as well.
Combining the quantum sensors with superconductors further stabilizes the system, reducing noisy data for more accurate results. Whether for long-term environmental pollution or more immediate hazards, quantum-based atmospheric detection offers a huge boost to air quality monitoring efforts in the region.
This article was first published in the July 2021 print version of Asian Scientist Magazine.
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Copyright: Asian Scientist Magazine. Illustration: Oikeat Lam/Asian Scientist Magazine.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.