Discoveries in 2021 dared the world to consider grand possibilities in physics, space and the origins of life. Will these bold claims hold up to scrutiny?
Scientists may have spotted stars made of antimatter (SN: 6/5/21, p. 8). Finding antistars challenges a basic tenet of cosmology — that the vast majority of the universe’s antimatter, matter’s oppositely charged doppelgänger, was destroyed long ago. In 10 years of observations from the Fermi Gamma-ray Space Telescope, researchers found 14 points of light emitting gamma rays at energies that are expected when matter and antimatter meet and annihilate each other — a process that could happen on the surface of antistars. The discovery hints that substantial amounts of antimatter may have survived. But proving the existence of antistars will be extremely difficult because, aside from the studied gamma rays, the light such stars give off would look just like the light from normal stars.
Nothing gets physicists more excited than evidence of a new fundamental particle. Researchers with the Muon g–2 experiment at Fermilab in Batavia, Ill., flung billions of muons around the lab’s giant magnet and found that the rate at which the orientation of the muons’ magnetic poles wobbled strayed from theoretical predictions. The odd behavior suggests that hidden particles are influencing the muons’ magnetic properties, challenging the standard model of particle physics describing the universe’s fundamental forces and elementary particles (SN: 5/8/21 & 5/21/21, p. 6). But it will take more data to convince physicists, who are still refining their predictions of muon behavior.