From 26th century BCE
Giza, Egypt
The Second Pyramid at Giza was identified in the passage as the pyramid belonging to King Chephren of the Fourth Dynasty, dated there to approximately 2600 BCE. Cosmic-ray probing conducted in 1969 located the king’s burial chamber slightly north of the centre of the base and found no unknown chambers or corridors in the upper third or throughout the pyramid.
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The Story
The Second Pyramid is associated with King Chephren and is assigned in the passage to the Fourth Dynasty, around 2600 BCE. Its monumental mass made direct inspection difficult, encouraging the use of cosmic rays as a non-destructive method for investigating hidden spaces. The experiment placed spark chambers inside a subterranean chamber so that the passage of muons through the structure could be measured.
The method relied on the different absorption of muons in solid rock and empty spaces. A hidden chamber or corridor would allow a greater intensity of cosmic rays to pass through than the surrounding stone. With two horizontally oriented spark chambers separated vertically by about 0.3 metres, investigators could detect a void and estimate its location to within a few metres before any excavation was attempted.
The results were announced on 30 April 1969 after computer analysis. They indicated that Chephren’s burial chamber was not exactly at the centre of the pyramid’s base, but lay a few metres to the north, confirming earlier surveying results. A second apparatus was then used to examine the whole pyramid, and the analysis reported no unknown voids, in agreement with archaeological expectations.
From 26th century BCE
Giza, Egypt
The Second Pyramid at Giza was identified in the passage as the pyramid belonging to King Chephren of the Fourth Dynasty, dated there to approximately 2600 BCE. Cosmic-ray probing conducted in 1969 located the king’s burial chamber slightly north of the centre of the base and found no unknown chambers or corridors in the upper third or throughout the pyramid.
Continue exploring
The Story
The Second Pyramid is associated with King Chephren and is assigned in the passage to the Fourth Dynasty, around 2600 BCE. Its monumental mass made direct inspection difficult, encouraging the use of cosmic rays as a non-destructive method for investigating hidden spaces. The experiment placed spark chambers inside a subterranean chamber so that the passage of muons through the structure could be measured.
The method relied on the different absorption of muons in solid rock and empty spaces. A hidden chamber or corridor would allow a greater intensity of cosmic rays to pass through than the surrounding stone. With two horizontally oriented spark chambers separated vertically by about 0.3 metres, investigators could detect a void and estimate its location to within a few metres before any excavation was attempted.
The results were announced on 30 April 1969 after computer analysis. They indicated that Chephren’s burial chamber was not exactly at the centre of the pyramid’s base, but lay a few metres to the north, confirming earlier surveying results. A second apparatus was then used to examine the whole pyramid, and the analysis reported no unknown voids, in agreement with archaeological expectations.