A team of researchers from Purdue have measured vacuum friction for the first time in history. By making the fastest spinning object ever with a laser-like 150-nanometer spinning silica ball, this team showed how a tiny ball of silicon dioxide that rotates 300 billion times per second has been able to detect torque, for the first time ever.  What is Vacuum Friction?  Hypothetically, an object in a true vacuum would never slow down based on air friction, but the vacuum itself is still thought to create friction that can slow the particles inside it. This has been hypothesized (and accumulated a consensus) in the last 10 years, but nobody has been able to actually measure friction inside a vacuum.  Previous Research In 2018, an international team of scientists (at the Institute of Photonics at ETH Zurich) got nanoparticles to spin a billion times per second –– which was the fastest mechanical rotation known to exist in history. The team wanted to focus on the ways light’s energy can move nanoparticles, with hopes to create quantum vacuum fluctuations –– virtual particles that appear and disappear.  “In quantum mechanics, there are quantum vacuum fluctuations. If a nanoparticle spins really fast, those kinds of virtual particles can perhaps provide friction,” says Tongcang Li, an assistant professor of physics and astronomy at Purdue University.  With nanoscale silica dumbbells approximately 100 nanometers in diameter, the team began shining circularly polarized light into the vacuum. The light beams that make up the circularly polarized light have electric fields which rotate as they move forward –– called optical tweezers. When the light hit the dumbbells, they began to spin… at a billion times per second.  How This is Different The team at Purdue used this previous research but found that by using a slightly different laser spinner, even in a near-vacuum, spinning particles could create friction. Specifically, the team put the silica balls (which are microscopic) in a vacuum, then blasted them with two different lasers that made them spin. In this micro-scale silica gravitron, spinning particles could move fast enough to generate measurable friction.  Not only is the detection of torque astonishing, but the team discovered their setup didn’t require supercooling. Instead, it worked at room temperature. One of the researchers commented, “Our calculations show that this system will be able to detect the long-sought vacuum friction near a surface under realistic conditions.” This detection shows that it’s possible to study torque within a vacuum, so the next step is to detect long-sought vacuum friction near a surface under realistic conditions. “The optically levitated nano rotor will also have applications in studying nanoscale magnetism and quantum geometric phase,” said the team.  Discover More With Apex Magnets Today For more exciting updates on all things magnetic, head to our blog or sign up for our monthly newsletter.