The Fifth Fundamental Force: The Chameleon Force?

The cosmos is expanding at a constant-accelerating rate, and we don’t know why. One hypothesis is something called the chameleon force, a fifth fundamental force on top of the four that we traditionally learn in grade school (gravitational, strong, weak, and electromagnetic). Physicists posit that the strength of the chameleon force would be dependent on its surroundings: in dense environments like planets, it would be weakened, but in the wider vacuum of space, it would have the strength to propel the expansion of the observable universe. But the chameleon force will only remain a theory unless we can experimentally test it. Peiran Yin, Jiangfeng Du, and their colleagues did just that in their recently-published findings in Nature Physics. They designed a detector with plastic films on a rotating, magnetically-levitated piece of graphite. If the chameleon force existed, physicists would expect that the films would cause each other to wobble slightly up and down. However, this research group didn’t detect any of this expected oscillation. So the hunt for the elusive chameleon force, if it exists at all, remains wide open. You can read more about this research here.  Author BioNatalie Wang is currently working on her undergraduate degrees in Neuroscience and Medicine, Science, and the Humanities at Johns Hopkins University as a Hodson Trust Scholar. Her research interests are in DNA damage and repair, as well as post-operative delirium in older patients. Natalie started volunteering with WIS PDX in 2019 as a member of the outreach and education team, and is now the producer and a co-host of WIS's podcast, WISterhood. When not listening to music or doom-scrolling on Twitter, she can be found checking closets for Narnia.