Physicists at the Institute of Photonic Sciences in Barcelona have built a molecular scale around a virus-sized glass bead that floats in a tiny vacuum chamber, held aloft by a focused infrared laser beam. According to a WIRED feature, the team says the device could become a compact sensor for high-frequency waves and possibly dark matter — the invisible substance that makes up 85 percent of all matter in the universe.
Research posted last week on the preprint server ArXiv described how the bead can reliably and consistently measure objects as small as an individual molecule, with considerably less error than existing molecular scales. When an object such as a molecule is attached to the floating bead, the physicists perturb it with a tiny force and determine the object's mass by observing how fast the bead oscillates, like a tiny metronome.
From Measuring Molecules to Probing Gravity
The scientists who invented the scale are now working on experiments to study how gravity works by measuring the minute gravitational forces that the bead and a nearby sliver of gold exert on each other, according to WIRED. The team also hopes to use the floating bead system to detect high-frequency gravitational waves, which the scientists believe would cause the laser suspending the bead to bend out of shape.
That type of wave could help physicists spot dark matter, something no one has yet been able to do directly. According to a separate WIRED story, the waves would be caused when a theoretical dark matter particle called an axion runs into the powerful forces given off by a black hole.
Whether the minuscule glass bead is up to the task of finally providing direct evidence of dark matter is yet to be determined. In the meantime, it shows that scientists are actively coming up with original ideas that are wildly different from the warehouse-sized detectors usually tasked with the search for dark matter.
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