The night sky looks calm, but in reality, invisible particles, cosmic rays, are constantly flying through us. Among them are electrons and their antimatter counterparts, positrons. When they collide with detectors on satellites or balloons, the instruments record their energy. And here lies the mystery: on a graph with energy on the horizontal axis and the number of particles on the vertical axis, you see not smooth lines but breaks and bumps. As if someone had added extra particles with specific energies to the overall stream.

To figure this out, researchers built a model in which cosmic electrons come from two sources. The first is a diffuse background: particles wandering through the Galaxy, gradually gaining energy from supernova explosions. The second is specific nearby objects, such as pulsars. A pulsar is a rapidly rotating neutron star that, like a lighthouse, sends out beams of radiation. Near such a lighthouse, electrons can be accelerated to enormous speeds. The scientists calculated how these particles travel to us, losing energy along the way due to interactions with light and magnetic fields.

It turned out that if you take into account not only the steady stream from a pulsar but also possible one-off outbursts, you can reproduce those very breaks in the spectrum. Particularly interesting are data from the Chinese satellite DAMPE, which measured energies up to several trillion electron-volts — thousands of times higher than the energy of particles in the Large Hadron Collider. The model with nearby pulsars fits these data points well. This means that to explain the observations, we don't need hypotheses about dark matter decay or other exotic processes — ordinary astrophysical sources suffice.

This approach helps distinguish the "ordinary" from the "unusual." If future data show a break that doesn't fit the pulsar model, that would be a signal to search for new physical phenomena. For now, the night sky continues to send us its encoded messages, and we are learning to read them.