The mystery surrounding the piece of yellow glass in the shape of a scarab that occupies the center of the iconic pectoral of Pharaoh Tutankhamun has been solved.
Glass found across the Egyptian desert was formed by an extremely powerful meteorite impact some 29 million years ago, solving a mystery that has created confusion and debates among experts for nearly a century.
Researchers from Curtin University believe that the origin of the so-called Libyan Desert Glass, found across the Saharan desert in Egypt and Libya was created when a massive asteroid exploded as it entered Earth’s atmosphere.
In nature, glasses are formed when sand and/or rocks, often high in silica, are heated to high temperatures and then cooled rapidly.
This type of glass has been found in ancient jewelry, including a scarab carved from the material which features in pectoral jewelry buried next to Pharaoh Tutankhamun. The scarab on King Tut’s chest plate is nearly pure silica.
The pectoral piece
As noted by the Grand Egyptian Museum, the center of this pectoral is adorned with a rare green desert glass scarab set on the body of a falcon, it symbolizes the sun. The front legs and wings of this composite creature support a celestial boat containing the left eye of Horus – the emblem of the moon – crowned by a silver moon disk with a crescent in gold.
The pharaoh Tutankhamun is depicted in the disk flanked by the moon god Thoth and by the sun god Ra-Horakhty in a protective pose.
Flowers and buds of papyrus and lotus plants, the emblems of Upper and Lower Egypt, form the base of the pectoral.
How the centerpiece formed
Long have experts debated on how the tiny green or yellow fragments scattered across the desert formed.
Researchers have argued that these fragments were created by an extremely powerful atmospheric air burst as asteroids, or Near Earth Objects, exploded while entering Earth’s atmosphere, shooting particles through the sky.
Such an airburst occurred in the distant past, as an asteroid flew over Egypt exploding in mid-air, dumping vast amounts of heat across the desert.
The scientists from Curtis University in Australia analyzed miniature rains of Zircon minerals in samples of the glass, revered from various places across western Egypt.
Evidence of asteroid strikes
The Zircons inside the glass are a kind of time capsule preserving evidence of a high-pressure mineral named reidite. Researchers say that this mineral only forms during a meteorite impact.
“It has been a topic of ongoing debate as to whether the glass formed during meteorite impact, or during an airburst, which happens when asteroids called Near Earth Objects explode and deposit energy in the Earth’s atmosphere,” lead author Dr. Aaron Cavosie, from the Space Science and Technology Centre in Curtin’s School of Earth and Planetary Sciences revealed in a statement.
“Both meteorite impacts and airbursts can cause melting, however, only meteorite impacts create shock waves that form high-pressure minerals, so finding evidence of former reidite confirms it was created as the result of a meteorite impact,” Dr. Cavosie explained.
Reidite, the key
The scientist argues that discovering the existence of reidite confirms it was created after a meteorite impact.
As noted by Dr. Cavocsie, the idea that glass may have formed during massive atmospheric airbursts gained fame after the 2013 airburst over Russia, which caused not only property damaged but injured humans on the ground.
“Previous models suggested that Libyan desert glass represented a large, 100-Mt class airburst, but our results show this is not the case,” Dr. Cavosie said.
“Meteorite impacts are catastrophic events, but they are not common. Airbursts happen more frequently, but we now know not to expect a Libyan desert glass-forming event in the near future, which is cause for some comfort.”