The ever-accelerating expansion of the universe may be driven by a mysterious form of matter called "unparticles," which do not obey the Standard Model of particle physics, a new theoretical paper suggests.
Scientists widely acknowledge that the universe is expanding, though the cause of that expansion remains elusive. One of the most popular proposed explanations is a mysterious entity called dark energy in the form of a cosmological constant, which leads to expansion at a rate independent of the age of the universe and the temperature of matter and radiation. However, recent astronomical observations challenge this hypothesis, prompting physicists to explore alternatives to what dark energy could be.
