Salvatore Capozziello

The universe is expanding, and the pace of that expansion is set by dark energy, the mysterious force accelerating the recession of galaxies. In the standard cosmological model, its density is constant: a cosmological constant, an unwavering metronome since the birth of the cosmos.

The universe is putting on a show, and the lead role goes to dark energy. For a long time, the actor seemed unchanging: the cosmological constant (the vacuum energy that accelerates cosmic expansion) set the same tone throughout.

The Universe is a grand highway where galaxies, like cars, are moving apart faster and faster. The gas pedal is controlled by mysterious dark energy.

An ordinary black hole is an abyss into which everything falls irretrievably. But a new model paints a different picture: at its edge, time freezes, and the hole becomes a frozen whirlpool. Light and matter don't fall in but stick fast to the surface — causing a bright spot to appear within the shadow.

For nearly a century, astronomers have watched galaxies spin as if held together by invisible mass. Fritz Zwicky first noticed it, and Vera Rubin precisely measured the speeds of stars at the edges.

Gravity is usually explained through the curvature of spacetime. Massive bodies press it down like a bowling ball on a stretched rubber sheet. But this approach has two lesser-known twins. In one, gravity arises from torsion (twisting) of spacetime; in the other, from its non-metricity (when lengths and angles change during transport).

A ball sits in a pit. It won't roll out on its own: it needs a push. But in the quantum world, a particle can leak through a barrier without extra energy. This trick is called tunneling.

Picture the early Universe as an unimaginably large bell. Inflation — the era of rapid expansion, dreamed up by Alan Guth, strikes it, sending a wave rippling across the fabric of spacetime.

A stone falls into still water — ripples spread across the surface. A black hole behaves similarly when something falls into it or when it merges with another black hole. The hole begins to oscillate, and these oscillations propagate through space as gravitational waves.