The Great Pyramid of Giza has a "big void" inside, at least a hundred feet long, discovered by cosmic rays and leaving scientists to ponder what’s inside and what it was used for. It's being called the discovery of the century.
The void, detailed in a study published by the journal Nature, is the first large inner structure found in the 4,500-year-old pyramid since the 1800s, National Geographic reported.
National Geographic said the space's size resembles that of the pyramid's Grand Gallery, the 153-foot-long, 26-foot-tall corridor that leads to the burial chamber of the pharaoh Khufu, who reigned from 2509 to 2483 B.C.
The void was located though the use of muon radiography, a technique that uses cosmic rays to detect cavities in massive structures, NatGeo said.
"We don't know whether this big void is horizontal or inclined; we don't know if this void is made by one structure or several successive structures," Mehdi Tayoubi from the HIP Institute, Paris, told the BBC News.
"What we are sure about is that this big void is there; that it is impressive; and that it was not expected as far as I know by any sort of theory," Tayoubi continued.
NatGeo said the cavity has a cross section similar to the Grand Gallery, the major corridor running through the pyramid.
"This is definitely the discovery of the century," archaeologist Yukinori Kawae, a National Geographic emerging explorer, told the magazine. "There have been many hypotheses about the pyramid, but no one even imagined that such a big void is located above the Grand Gallery."
The Nature study's abstract said there is no current information about the role the void played.
"Despite being one of the oldest and largest monuments on Earth, there is no consensus about how it was built," researchers wrote in the Nature study's abstract. "…The resulting cosmic-ray muon radiography allows us to visualize the known and potentially unknown voids in the pyramid in a non-invasive way.”
"… This void, named ScanPyramids Big Void, was first observed with nuclear emulsion films installed in the Queen's chamber (Nagoya University), then confirmed with scintillator hodoscopes set up in the same chamber and re-confirmed with gas detectors outside of the pyramid."