Axions: How Small Can Their Share of Dark Matter Be?
Dark matter is an invisible substance that reveals itself only through gravitational effects: it bends the light of distant galaxies, much like an unseen window that alters the path of light rays.
Weighing Neutrinos: How Much Does a Ghost Particle Weigh?
In 1998, physicists caught neutrinos doing something astonishing: the particle changes its type on the fly. That is only possible if it has mass. This became the only laboratory proof of physics beyond the Standard Model. But exactly how much a neutrino weighs remains a mystery.
Through the Fog: How Free Electrons Blur Ancient Light
Imagine looking at a distant mountain range through morning fog. The peaks' outlines are blurred, and if the fog is patchy, some slopes fade more than others. That's roughly how astronomers see the ancient light of the universe, which has been traveling to us for 13.8 billion years.
This light was born when the universe was just 380,000 years old, long before the first stars.