electron mass

Water in a glass looks continuous, but it's actually a dance of trillions of molecules constantly breaking and forming bonds. Seeing this dance in full detail was previously impossible: accurate calculations that account for the quantum properties of electrons could only handle tiny droplets of a few hundred atoms. The new model UBio-MolFM changes the game.

An electron beam is a stream of tiny particles carrying an electric charge. When such a beam hits a material, it doesn't just heat it or knock out atoms: it also gives the surface a slight push, like a jet of water pushing against your palm.

The mystery of the main break in the spectrum of galactic cosmic rays, the knee at 3 PeV, has persisted for nearly a century.

A drop of water stretches in a strong electric field. The deuterium nucleus, a bound pair of a proton and a neutron, behaves the same way, except here the field comes from a passing gamma ray, and instead of just stretching, the nucleus can simply fall apart.

To uncover the proton's true size, physicists swapped the electron in a hydrogen atom for its heavy copy — the muon. Acting like a magnifying glass with thousandfold power, the muon gets right up against the nucleus and 'probes' the proton with unprecedented precision.

In the basement of a laboratory in Jyväskylä, a trap holds a single atom aloft, like a magician balancing a ball on a fingertip. The tin-113 atom is unstable: sooner or later it captures one of its own electrons and becomes indium-113, emitting an elusive particle — the neutrino. How much energy is released in the process was previously known only approximately.

In an underground ring 27 kilometers in circumference, protons are accelerated to nearly the speed of light and smashed head-on. At the collision point, conditions briefly recreate those of the first trillionth of a second after the birth of the universe.

Two teams of radio telescopes pointed their antennas at two gas clouds: one at the very center of the Milky Way, the other in its quiet outskirts. Both clouds contain methanol molecules — an alcohol that acts as a tiny pendulum in space: it absorbs and emits radio waves at strictly defined frequencies.

The gas in a galaxy glows like a neon sign, and by the color of that glow, astronomers can tell how hot it is. The logic is simple: the more heavy elements (which astronomers call metals) in the gas, the better it cools. So galaxies rich in metals should have cooler gas. But new observations show the opposite.

The nucleus of deuterium, or the deuteron, can be pictured as a microscopic spinning top. If its charge distribution is not perfectly symmetric, then in an external electric field this top experiences a minuscule tilt of its spin axis.

Gamma rays are the most energetic flashes of light born deep within atoms. Their energies are like fingerprints: each radioactive element has its own pattern. But measuring that pattern with high precision is like weighing a grain of sand on a scale sitting on a vibrating truck. The new setup works like an ultra-sensitive thermometer.

The neutron is a particle with no charge but with internal structure. Like a ball that looks smooth on the outside but has a complex filling inside. Scientists have long wanted to understand how electric and magnetic forces are distributed inside the neutron. To do this, you need to "feel" it — collide it with its antiparticle and see what happens.

Since the days of Galileo, it was believed that in a vacuum all bodies fall identically. Einstein elevated this to a principle: gravity travels at the speed of light and is the curvature of spacetime.