Scientific American recently asked a variety of physicists: What is the most surprising discovery in your field? Some common themes included the expansion of the universe, neutrinos and their oscillations, and black holes. Particularly surprising was dark energy. “None of us working in physics saw that coming!” said Katherine Freese, theoretical astrophysicist at the University of Texas at Austin, about the unidentified force that makes up most of the universe. Physics is full of such mind-bending discoveries, many of which have only just been made.

Take our baffling universe. Recent data from the James Webb Space Telescope reveal giant galaxies that formed only a few hundred million years after the big bang, conflicting with the generally accepted time line of cosmic events. Those who work on the so-called expansion problem in physics (two measurements of the universe that don't agree) eagerly await further data from JWST and several other important telescopes coming online this decade. An upcoming experiment housed deep underground in a Sardinian mine is designed to determine the weight of empty space—yes, it weighs something—and could help solve some of these conundrums.

In other laboratories on Earth, researchers have designed materials that manipulate light waves to make cloaking devices and other cool tech, and materials simulated with light waves are revealing inexplicable physics. Some exotic materials change states of matter regularly over time much like atomic crystal structures repeat in space, and scientists recently transformed the matter phase of a substance and simultaneously opened a new dimension in time.

Nothing alters spacetime more than black holes, which may connect through wormholes to other black holes. The black hole boundary, called the event horizon, is where all light is swallowed up, and studying it might explain what is beyond the observable edge of the universe.

The physics of the event horizon is a long-standing problem in quantum mechanics. Researchers have announced they have a way to study what happens to matter falling into a black hole by harnessing the elusive glow of space particles during rapid acceleration. Electrons are crucial to quantum experiments, though fundamentally perplexing: they have spin, which gives them quantum properties, but they themselves can't spin. So where does their spin come from? Such brainteasers are common in quantum physics, whose underlying mathematical foundations could not exist without appropriately called imaginary numbers.

Confounding these complexities is the work of Nobel-winning physicists who ran experiments on entangled photons and determined that objects may lack definite properties until they are observed (by us, namely). This work stemmed from the mystery of how quantum theory itself works. For every puzzle in physics, there is a team looking for an answer, which in turn cracks open a nesting doll of additional puzzles. And perhaps that is the most surprising thing about physics.