The Particle That Passes Through Earth

Written by Studio AM.

Every second, enormous numbers of neutrinos pass through your body and continue through Earth. They arrive from the Sun, from exploding stars, and from reactions high in the atmosphere. Yet you do not feel them. A neutrino has no electric charge and interacts with ordinary matter mainly through the weak nuclear force, which acts at extremely short range. Most neutrinos cross atoms without disturbing them.

That indifference makes neutrinos valuable messengers and difficult objects to study. Light from the center of the Sun may take a very long time to work outward, repeatedly meeting charged particles. Neutrinos leave almost immediately, carrying information about reactions in the solar core. However, the same weak interaction that lets them escape also lets them pass unnoticed through a laboratory.

Researchers answer this problem with scale and patience. Some detectors use huge tanks of water or other clear materials, placed deep underground to screen out more common particles. On rare occasions, a neutrino strikes a particle in the tank. The collision produces a faint pattern of light that sensitive instruments record. Scientists then compare many such flashes, their directions, and their energies. No single flash tells the whole story. Evidence emerges from a large collection of unlikely events. A neutrino detector therefore works by accepting an apparent contradiction: to observe particles that barely touch matter, researchers give them an immense amount of matter to cross.

Questions

Choose an answer. The explanation appears after you answer.

  1. Question 1 of 4

    What is the main idea of the passage?

  2. Question 2 of 4

    Why are neutrinos able to carry relatively direct information from the solar core?

  3. Question 3 of 4

    What does “indifference” mean in the passage's description of neutrinos?

  4. Question 4 of 4

    What is one purpose of placing some neutrino detectors deep underground?

Score: none answered yet.

More passages

Practise reading