A third round of ground penetrating radar (GPR) scanning is underway inside the burial chamber of King Tutankhamun, Egypt's Ministry of Antiquities announced today, as part of an effort to answer a question that has long intrigued and stumped researchers: Are the walls of the famous tomb hiding other chambers—perhaps another royal burial concealed for more than 3,300 years? 
 
 Ever since archaeologist Howard Carter discovered the treasure-packed tomb in Luxor's Valley of the Kings in 1922, experts have believed the space to be strangely small for a pharaoh. Various theories about the tomb have been proposed over the decades, but in 2015 Egyptologist Nicholas Reeves suggested an astounding possibility: The north and west walls might conceal the mummy—and fabulous possessions—of Tut’s stepmother, the legendary beauty Queen Nefertiti. 
 
 What King Tut’s tomb is hiding Stairway Scientists are investigating whether there are hidden chambers behind the north and west walls of King Tut’s tomb. 25 feet Treasury Antechamber Burial chamber Annex Hidden room? NORTH Hidden room? NG STAFF PHOTO: Kenneth Garrett SOURCES: THEBAN MAPPING PROJECT, Ministry of State for Antiquities What King Tut’s tomb is hiding Scientists are investigating whether there are hidden chambers behind the north and west walls of King Tut’s tomb. Stairway 25 feet Treasury Antechamber Burial chamber Annex Hidden room? NORTH Hidden room? NG STAFF PHOTO: Kenneth Garrett SOURCE: THEBAN MAPPING PROJECT. Ministry of State for Antiquities 
 
 Two previous scans of the burial chamber, conducted in 2015 and 2016, varied in their results and were determined inconclusive. A third non-invasive GPR scan was commissioned by Egypt’s Minister of Antiquities Khaled El Enany following the recommendation of experts who met in 2016 to study the results of the previous scans. This latest investigation, conducted under the direction of the Polytechnic University of Turin, aims to resolve those results and verify whether or not there are voids behind the walls. 
 
 Intriguing Clues 
 
 Reeve’s idea was prompted by a highly detailed 3D scan of the tomb conducted in 2009 by the firm Factum Arte, which was tasked with building an exact replica of the tomb for tourists to visit. When Reeves studied the scans of the north and west walls, he believed he saw traces of openings that had been bricked up and plastered over. Those features could help explain two other puzzling features. 
 
 In 1984 Egyptologist Gay Robins published a paper about the proportions of the figures painted on the walls of the burial chamber. On the north wall they followed a 20-square grid, but on the other three walls they followed an 18-square grid. Robbins thought that might have been the result of the rushed preparation of the tomb, which could have involved separate teams of painters trained in two different traditions. But what if the walls had been painted at two different times—after one burial was sealed, and then again when another burial was added some years later? 
 
 Experts from the Getty Conservation Institute in 2012 noticed something else that was strange. The background of the north wall was originally painted white but later repainted yellow to match the other three walls. Did the white background date to the first burial, and the repainting to the time of Tut? 
 
 When Mamdouh El Damaty, Minister of Antiquities at the time Reeves put forward his theory, took a close look at the north wall, he saw another irregularity in one area—a clear difference between two wall treatments. The upper part of that area displayed paint on bare stone, but the lower part was paint on smeared plaster. 
 
 The collection of evidence was convincing enough for El Damaty to approve infrared thermography of part of the north wall in early November 2015. The imaging technique detects variations in surface temperatures, which presumably would be different for a solid limestone wall and one concealing a room, if there was one. The imaging revealed tantalizing temperature differences on the north wall. 
 
 Later that month, Japanese radar specialist Hirokatsu Watanabe used GPR to peer behind the tomb walls. The results were sensational and made headlines around the world. Watanabe thought he could see chambers behind the north and west walls, as well as artifacts of metal and organic materials. 
 
 But many Egyptologists and GPR experts had serious doubts about the results of that survey, so a second round of GPR was launched in March 2016. This time National Geographic engineers carried out the work. 
 
 Expectations were huge, but the results were puzzling. The survey was designed to look for walls of the same thickness that Watanabe had seen, but it didn’t pick up anything like that—or any hint of voids to the north or west of Tut’s burial chamber. 
 
 The results of those two probes brought the investigation to a standstill. The project needed a tiebreaker. 
 
 Results: Yes or No? 
 
 The third GPR survey will leave no stone unturned by radar technology, with plans calling for several four-hour sessions of scanning. The results of the completed work should hopefully provide the final answer on whether there are hidden chambers or not. Scientists caution, however, that the GPR scans can only detect “anomalies” in the rock, and further research will be required to determine if any anomalies are in fact hidden rooms. 
 
 The current project, a joint scientific mission between Egypt and Italy, is being coordinated by Italian physicist Francesco Porcelli from the Polytechnic University of Turin in partnership with the University of Turin and three private companies, Geostudi Astier, 3DGeoimaging, and Terravision. 
 
 “I'm privileged to be given this opportunity, and I'm privileged to be coordinating such a great team,” Porcelli told National Geographic during a break between scanning sessions on Thursday evening. 
 
 The GPR team works through the night, after the Valley of the Kings and Tut's tomb are closed to tourists. The researchers carefully navigate their high-tech equipment in the tight spaces of the burial chamber under of the supervision of Egyptian officials, careful to ensure that the radar antennas scan as close as possible to the wall surfaces without disturbing the priceless paintings of the 3,300-year-old tomb. ||||| CAIRO -- Archaeologists are starting radar scans of the tomb of famed pharaoh Tutankhamun in the southern city of Luxor, Egypt's Antiquities Ministry said Thursday. The scans will be carried out over a week to check for the existence of any hidden chambers behind the tomb, according to the ministry. 
 
 Egypt carried out previous scans as part of the quest, but the findings were inconclusive. 
 
 The tomb of King Tut, who ruled Egypt more than 3,000 years ago, was discovered in 1922 in the Valley of the Kings, located on the west bank of the Nile river in Luxor. For many, Tut embodies ancient Egypt's glory because his tomb was packed with the glittering wealth of the rich 18th Dynasty from 1569 to 1315 B.C. 
 
 What killed King Tut? Researchers may have finally found out 
 
 Scanning techniques have been used for other purposes. The BBC reported late last year that techniques developed in London reveal what is written on the papyrus that mummy cases were made from. Ancient Egyptians used the scraps of papyrus for shopping lists or tax returns. 
 
 "Because the waste papyrus was used to make prestige objects, they have been preserved for 2,000 years," said Adam Gibson of University College London, the BBC reported. 
 
 "And so these masks constitute one of the best libraries we have of waste papyrus that would otherwise have been thrown away so it includes information about these individual people about their everyday lives."
– The theory that King Tut's tomb also holds the remains of his stepmother, the legendary Queen Nefertiti, has tantalized Egyptian archaeology for nearly three years. But after two scans with ground-penetrating radar proved inconclusive, National Geographic reports that third major scan is underway at the tomb in Luxor's Valley of the Kings, and it has exclusive photos of the operation. The scan will search the walls of Tut's tomb for signs of a hidden chamber and is expected to take about a week, reports CBS News. Several weeks of analysis will then follow. Egyptologist Nicholas Reeves believed he saw telltale signs—traces of sealed entrances in the north and west walls of Tut's tomb—in a 2015 scan. It's also been determined that the north wall was initially painted a different color than the others, while paintings on the wall also follow a different pattern than those on the others. This might suggest the wall—where infrared thermography found temperature variations—was built some time before the others. But though experts said a 2015 scan indicated chambers present behind the north and west walls, a second scan in 2016 found nothing. The third scan, being led by the Polytechnic University of Turin, aims to settle whether any voids in the rock exist. If so, archaeologists would then begin the next phase of seeing what's inside them. (Tut's dagger is out of this world, literally.)