Art & Culture

Hidden corridor unearthed in Pyramid of Giza using Cosmic-Ray Muon Radiography

Scientists discovered a hidden corridor inside the Great Pyramid of Giza using a non-invasive technique known as cosmic-ray muon radiography.

What is CMR (Cosmic-Ray Muon Radiography)?

  • CMR is a technique for studying the density and composition of materials hidden within large and dense objects like geological formations, archaeological sites, and industrial facilities.
  • Muons, a type of cosmic-ray particle, are used in the technique to generate images of the interiors of such objects.
  • When cosmic rays, mostly protons and atomic nuclei, collide with atoms in the Earth’s upper atmosphere, muon particles are produced.
  • These muons travel through the atmosphere and into the ground, passing through objects along the way.
  • Muons are highly penetrating particles that can penetrate several metres of rock or other materials, making them ideal for imaging an object’s internal structure.

Working principle

  • CMR works on the principle of measuring the flux of muons passing through an object and comparing it to the expected flux based on the geometry and composition of the object.
  • Differences between measured and expected flux indicate variations in the object’s density or composition, which can be used to construct an image of the object’s internal structure.


  • Among the most important applications of cosmic-ray muon radiography are:
  • Volcano monitoring: Scientists can better understand the structure and potential eruption hazards of volcanoes by using muon radiography to create images of their interiors.
  • Muon radiography can be used to explore the interiors of pyramids and other ancient structures without causing damage to them.
  • Muon radiography can be used to detect the presence of nuclear materials within reactors and to track their condition over time.

Great Pyramid of Giza

  • The Great Pyramid is the largest of Giza’s three pyramids, standing approximately 147 metres above the Giza plateau.
  • Construction began in 2550 BC, during the reign of Khufu, widely regarded as Egypt’s greatest pharaoh.
  • It is estimated that 2.5 million stone blocks weighing between 2.5 and 15 tonnes were used to construct the pyramid.
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