radioactive decay

After a nuclear explosion, soot rises into the sky. It settles high above the clouds, in the stratosphere, and stays there for years. This soot acts like a thick curtain: it blocks some sunlight and alters the chemistry of the sky.

Diamond is a symbol of perfection, but its true magic is revealed through flaws. Perfect lattice purity gives transparency and hardness, while defects, such as color centers, open a portal to the quantum world, becoming the foundation for quantum computers and quantum sensors.

The Standard Model is a set of rules for all known particles. But it says nothing about dark matter, which makes up a quarter of the Universe. To find it, you don't need to build city-sized colliders. Radioactive molecules act like sniffer dogs: their incredible 'scent' picks up the faintest traces of unknown forces that slip past giant machines.

When many excited atoms are gathered together, they often fire light in concert, like a crowd clapping in rhythm. This well-known phenomenon is called Dicke superradiance. But the authors of the new study asked: what happens if the atoms are not identical and each one feels its neighbors?

A swing only gets going if you push it in rhythm. Miss the beat, and your effort is wasted. Light interacts with an atomic nucleus in much the same way: a photon is usually absorbed only when its energy exactly matches the gap between nuclear levels. But what if the photon's energy doesn't fit? The authors of a new study have found a workaround.

In a molecule resembling chlorophyll and built from carbon, a metal atom at the center acts as a toggle. Shifting it by fractions of a nanometer can make the molecule glow, quench, or boost its brightness a hundredfold.

Molecules in a solution behave like a crowd in a square: they can jostle randomly or line up in neat rows. An aqueous solution of disodium cromoglycate is a well-known model for chromonic liquid crystals, where such 'rows' form spontaneously. But if you shine ultraviolet light on the solution, order collapses: molecules start breaking apart.

A tiny glass sphere floats in a laser beam like a speck of dust in sunlight. Inside it is radioactive lead, which decays from time to time. Each decay ejects charged particles, and the sphere loses or gains a tiny electric charge.

An atomic nucleus isn't always round. It can stretch out like a melon or flatten like a pumpkin. And its size depends on this shape — just as the size of a pie depends on the shape of the dough. Scientists calculated the shapes and sizes of nuclei of berkelium isotopes — a heavy element produced in reactors.

In the stream of charged particles that constantly blows from the Sun, radio bursts sometimes occur — short, powerful signals at frequencies you can pick up on an ordinary radio. Until now, it was unclear how exactly these signals are born in that stream.

In a pot of boiling soup, small bubbles churn, but gradually large-scale flows come to dominate. Something similar happens in cosmic plasma, where magnetic fields behave like tangled threads.

Emptiness isn't always empty: it can hide energy, like supercooled water hides ice. Physicists call this false vacuum — a state that only needs a nudge to cascade into the true one.

A thin film of thorium dioxide, just 10 nanometers thick, is deposited on a steel disk. A laser pulse strikes it, but instead of the expected glow, the detector catches a stream of electrons.