radioactivity

In 1976, physicists predicted that an electron could do more than just fly past a nucleus: it could slam into it, transferring energy and making the nucleus 'shudder.' They called this effect NEEC — nuclear excitation by electron capture. But for nearly fifty years, no one has managed to observe it in an experiment.

A string sounds perfectly pure until a draft touches it. That's roughly how a superradiant laser works: a beam of atoms, pre-charged with energy, flies through a room made of two mirrors — an optical resonator (a trap where light bounces back and forth).

A quantum computer is like an orchestra where each ion is a musician and laser pulses are the conductor's baton. But if someone in the audience rustles, the delicate melody of quantum states goes off key.

An atomic nucleus is like a crowded bus. To free up space, a group of two protons and two neutrons — a helium nucleus, an alpha particle — exits through the front door: this is alpha decay, described by George Gamow as tunneling under an energy barrier.

In the first minutes of the Big Bang, the universe whipped up a cocktail of hydrogen, helium, and a pinch of lithium.

Radio pulsar J1574+4703 behaves like a finicky lighthouse. Instead of shining steadily, it turns its radio beam on in short flashes and then falls silent for long stretches. Objects like this are called 'rotating radio transients', or RRATs for short.

An atomic nucleus usually follows its own rules: its decay doesn't care about temperature, pressure, or molecular neighbors. But the uranium-235m isotope is a striking exception. This nucleus sits in an excited state, like a tightly coiled spring, and sooner or later it releases the extra energy.

A multitude of atoms can act like a synchronized orchestra: if each emits light in unison with the rest, the flash becomes many times brighter. This is superradiance — a phenomenon well studied in the lab, but almost never sought in space. Now astrophysicists suspect that such collective 'notes' also play out in interstellar space.

In the first minutes after the Big Bang, the Universe was like a blazing hot stove. On it, according to the 'recipe' of the standard theory, hydrogen, helium, and a bit of lithium were supposed to cook. But telescopes see only a third of the lithium that this recipe calls for.

The scorching gas streaming from the Sun is not a continuous flow but rather a soup of charged particles. In this soup, waves constantly boil up: electric fields flare and fade like ripples on water from a tossed stone. One such wave is the ion-ion acoustic wave.

At the heart of every galaxy slumbers a supermassive black hole. When it devours matter, its surroundings flare up: this is an active nucleus. How can we learn about past outbursts if the black hole is silent? The answer lies in light echoes.

Deep inside stars, light nuclei fuse, giving birth to helium and streams of neutrons. On Earth, we recreate this process by combining deuterium and tritium — special isotopes of hydrogen.