Relentless cosmic bombardment strikes Earth every second, revealing alarming reality

Trillions of "ghosts": what is known about neutrinos?

The most common cosmic travelers are neutrinos - extremely light elementary particles with no electric charge that rarely interact with ordinary matter.

According to Michael Pravica, a physics professor at the University of Nevada, Las Vegas, about 100 trillion neutrinos pass through each person's body every second.

Nature of neutrinos:

• Origin sources: The vast majority are produced by thermonuclear reactions in the Sun's core. A smaller portion arrives from distant galaxies where supernova explosions occur, or from matter falling into supermassive black holes.
• Interaction with the body: Throughout a person's entire life, only one or a few of these particles may collide with an atom in their organism.
• Safety: Because they have no charge and very little mass, neutrinos pose no radiation risk.

Scientists detect these particles using special detectors, such as the IceCube Observatory in Antarctica, where a cubic kilometer of ice is equipped with thousands of light sensors to capture rare flashes from neutrino collisions with atomic nuclei.

Muon cascades and natural radiation

In addition to neutrinos, Earth is constantly bombarded by primary cosmic rays - protons and heavy element nuclei (from helium to iron) accelerated to nearly the speed of light.

Colliding with air molecules in the upper atmosphere, they create cascades of secondary particles, among which muons predominate.

Muons are heavier counterparts of electrons with a negative charge. They reach Earth's surface with varying intensity.

What exactly is that intensity?

• At sea level: Approximately one particle passes through an area of 1 square centimeter every minute.
• Through the human body: Several dozen to hundreds of muons pass through every second (approximately 1–2 particles per second through the palm alone).

Although muons and accompanying neutrons have electric charge and contribute to the natural radiation background, their impact is minimal.

The cumulative dose of cosmic radiation for an average person is about 0.4 millisieverts per year (comparable to several chest X-rays) out of a total natural background of 2.4 millisieverts.

What does this mean for research?

The ability of cosmic particles to pass through dense objects is widely used in modern science. Using muon detectors, physicists have already been able to scan internal cavities of ancient Egyptian pyramids.

Meanwhile, high-energy neutrinos enable astrophysicists to study the most extreme corners of the universe, from which ordinary light or radio waves cannot escape due to high matter density.