Q&A

Do muons reach Earth?

Do muons reach Earth?

Muons are by-products of cosmic rays colliding with molecules in the upper atmosphere. Muons reach earth with an average velocity of about 0.994c. On earth’s surface, about 1 muon passes through a 1 cm2 area per minute (~10,000 muons per square meter in one minute).

What is the flux of muons reaching the Earth?

about 1 muon per square centimeter per minute
Most muons observed at the surface of the Earth are produced by primary cosmic rays in the upper atmosphere. They are the most numerous energetic particles arriving at sea level, with a flux of about 1 muon per square centimeter per minute.

Can we find muons in cosmic rays?

Muons in the atmosphere, a component of cosmic rays. Atmospheric muons are an essential component of cosmic ray showers. When a high energy primary particle coming from space collides with a nucleus of the upper atmosphere, it generates a spray of particles which later interact in their turn.

Do cosmic rays reach Earth surface?

Cosmic rays constantly rain down on Earth, and while the high-energy “primary” rays collide with atoms in the Earth’s upper atmosphere and rarely make it through to the ground, “secondary” particles are ejected from this collision and do reach us on the ground.

Can muons travel faster than light?

Muons are subatomic particles that live for just 2.2 microseconds. (There are 1 000 000 microseconds in a second.) Even moving at nearly the speed of light, a muon should only be able to travel about 700 meters before it decays, so you might think no muons could ever reach Earth.

Can we see muons?

While cosmic ray showers are common from high-energy particles, it’s mostly the muons which make it… [+] Individual, subatomic particles are almost always invisible to human eyes, as the wavelengths of light we can see are unaffected by particles passing through our bodies.

How does atmospheric pressure on Earth affect the number of cosmic rays that hit Earth?

During each of the months analysed, a negative correlation between cosmic ray count and pressure was found. At higher pressures there is a greater amount of material for the charged particles to pass through. Therefore there are more collisions between secondary particles and air molecules.

Where are muons created?

high atmosphere
Muons are produced in interactions that occur in the high atmosphere between nuclei of gaseous molecules and primary cosmic rays, which are mostly high-energy protons.

Why are muons so important?

This rate of natural background radiation increases at higher elevations. Ultrasensitive detectors, including some neutrino and dark matter experiments, are placed deep underground to minimize the effect of atmospheric muons. Muons can help detect dangerous nuclear material and see into damaged nuclear power plants.

Can cosmic rays harm us?

They even permeate us, sailing straight through our bodies. One such mystery is cosmic rays, made of tiny bits of atoms. These rays, which are passing through us at this very moment, are not harmful to us or any other life on the surface of Earth.

How are muons created in a cosmic ray?

Cosmic ray muons are created when cos- mic rays enter earth’s atmosphere where they eventually collide with an air molecule and ini- tiate a hadronic shower|a cascade of particles (mostly pions) that may undergo further nu- clear reactions.

Why are muons the most energetic particles at sea level?

Muons are the most numerous energetic charged particles at sea level. A charged particle cannot avoid losing energy by ionization. As it passes through matter the charged particle interacts with the electric fields and typically knocks loose some of the loosely bound outer electrons.

How does a muon interact with other particles?

Muons are the most numerous energetic charged particles at sea level. A charged particle cannot avoid losing energy by ionization. As it passes through matter the charged particle interacts with the electric fields and typically knocks loose some of the loosely bound outer electrons. A muon interacts very little with matter except by ionization.

How are muons generated in a natural radiation shower?

This is about half of the typical total natural radiation background. Muons (and other particles) are generated within a cone-shaped shower, with all particles staying within about 1 degree of the primary particle’s path. 1/cos ( q ). (See “Slant Depth” later.)