"The "fifth force" may pose a challenge to the Universe origin-related standard cosmological concept known as the Lambda cold dark matter (ΛCDM) model." by Oleg Burunov via sputniknews image: CC BY-SA 4.0 / Illustris Collaboration / Dark Matter and gas Dark matter, which appears to make up most of the Universe's mass, remains one of the biggest mysteries that scientists have repeatedly tried to solve. Shedding light on the origin of the Universe is never easy. Researchers, however, aren't sitting on their hands, with two scientists having recently suggested the existence of a new "fifth force" in outer space. The "fifth force" may pose a challenge to the Universe origin-related standard cosmological concept known as the Lambda cold dark matter (ΛCDM) model. In a study yet to be peer-reviewed, two researchers from the University of Nottingham claimed that hypothetical particles known as symmetrons could prod the "fifth force" to form "domain walls," or invisible boundaries in space.