Scientists Uncover Ancient Star Map Using Powerful X-Ray Technology

At the SLAC National Accelerator Laboratory in Menlo Park, California, researchers have turned their attention to ancient parchment, employing advanced X-ray technology to uncover what may be the world’s oldest star map. This groundbreaking work focuses on a manuscript dating back over 2,100 years, attributed to the Greek astronomer Hipparchus.

The star catalogue, which is thought to have cataloged more than 800 celestial bodies, has only been referenced in historical texts, such as those by Pliny the Elder in the first century. Scholars believe that Hipparchus’s original work detailed the brightness and positioning of stars, along with illustrations of constellations. Unfortunately, the original document has never been located.

Recent investigations have revealed that a medieval manuscript, discovered at a monastery in Egypt’s Sinai Desert, contains remnants of this ancient star map. Created around the 6th Century, the manuscript was later overwritten with Christian texts by monks at St. Catherine’s Monastery.

Lead researcher Victor Gysembergh from the French National Centre for Scientific Research expressed his enthusiasm during a recent imaging session. “I’m at the peak of my excitement right now,” he said, as he observed ancient Greek text emerging on a computer screen. “We just have line after line of text showing up. I’m hoping to see the first star coordinates pop up. This could be a real change in our understanding of early astronomy.”

The star map faced erasure in the 10th Century, with the valuable goat- or sheep-skin parchment being repurposed. In 2012, a student at the University of Cambridge discovered a faint passage regarding astronomy within the manuscript, now known as the Codex Climaci Rescriptus.

In subsequent years, enhanced imaging techniques revealed more details. Researchers matched the star coordinates to historical celestial positions, allowing them to date the map back to Hipparchus’s era in the 2nd Century B.C.. This connection was further supported by references from later astronomers, such as Ptolemy.

Currently, scientists at SLAC are utilizing X-ray beams from the facility’s synchrotron particle accelerator—one of the most advanced high-energy X-ray facilities in the United States—to reveal further details of the star map. The manuscript comprises 22 pages, each comparable in size to standard hardcover book pages, inscribed on both sides with visible text alongside smudged remnants of the star map.

Researchers have noted the impressive accuracy of the coordinates being uncovered, especially given that they were created with the naked eye. The pages were transported to SLAC in a moisture-controlled case from the Museum of the Bible in Washington, D.C.

At SLAC, each page is carefully positioned before a steel nozzle that directs powerful X-rays onto the parchment. The intensity of the beam far exceeds that of conventional medical X-rays, enabling scientists to detect the subtle chemical traces of erased ink. Minhal Gardezi, a physics researcher from the University of Wisconsin and a member of the Hipparchus team, highlighted the complexity of the manuscript, noting that some pages feature up to six layers of ink from different eras.

As the team continues their work, anticipation mounts. “We have the word for Aquarius,” Gysembergh said, referencing the emerging text. “It could be a section where the manuscript is counting how many stars there are in a constellation, which would be great.”

The use of X-ray technology in historical manuscript analysis is rapidly evolving. SLAC has previously applied similar techniques to other significant documents, such as pages from the Gutenberg Bible and Confucian texts from Korea. These investigations not only contribute to historical knowledge but also enhance understanding of ancient scientific achievements.

The ongoing effort to unveil the star map of Hipparchus could redefine early astronomical history, offering a glimpse into the celestial observations that shaped the foundations of modern astronomy. As the researchers unveil more details, the excitement surrounding this project continues to grow, promising to answer longstanding questions about humanity’s journey in understanding the cosmos.