The fascinating story of the origin of an element in Tutankhamun’s scarab brooch continued this week. It was determined that some of the material found in that brooch was the result of a phenomenological event that occurred 28 million years ago. The aftermath of an incomprehensibly ancient comet hurtling through space toward Earth created a piece that was later used as the centerpiece on King Tut’s brooch. But there has been some debate about exactly how this event created the glasses. Now scientists from Australia and Austria think they have evidence to end the debate.
Small but important
The finds at Tutankhamun’s tomb are numerous and an artifact as small as a brooch can be overshadowed by heavier objects. But sometimes humble items have a deeper story than what you initially see. This impressively preserved brooch has an unimaginably deep history that has only come to light through thorough research from many fields. The striking yellow-brown scarab brooch is made from yellow silica glass stone taken from the sand of the Sahara desert, then shaped and polished by some ancient Egyptian artist. Perhaps this species of beetle has the most interesting history.
Tutankhamun’s brooch holds evidence of an ancient comet striking Earth
Unlock the sands of time
Chemical analysis shows that silica glass from this desert was originally formed 28 million years ago, when a comet entered the earth’s atmosphere above Egypt. The underlying sand was heated to a temperature of around 2,000 degrees Celsius and resulted in the formation of large amounts of yellow silica glass, scattered across a 6,000 square kilometer area in the Sahara desert.
In 2017, this type of silica glass was one of the clues that led Professor Jan Kramers of the University of Johannesburg, South Africa, and colleagues to a remarkable discovery. The other important discovery was a small black diamond-bearing pebble that the researchers named ‘Hypatia’, which had been found a few years earlier by an Egyptian geologist. This provides the clues needed to detect the catastrophic event and the resulting desert composition. The discovery of tiny diamonds inside the stone as a result of extreme pressure often deep within the earth’s crust is remarkable. This pebble was found on the surface and so the diamonds were formed as a result of a large shock – an impact of some kind. The team’s conclusion is that the pebble represents the first known specimen of a comet nucleus (rather than a conventional meteorite) and provides the first clear evidence of a comet striking Earth millions of years ago.
The latest research supports this claim
However, there has been some debate about the specifics of how this catastrophic event created glass. Questions remain as to whether this event was a true comet strike or a near miss.
In a Curtin University press release, Dr Cavosie, from the Center for Space Science and Technology in Curtin’s School of Earth and Planetary Sciences, said: “The topic of ongoing debate is whether glass forms during a meteorite impact or during a mid-air explosion, which occurs when asteroids called Near-Earth Objects explode and deposit energy in Earth’s atmosphere .”
The team believes that new evidence found in their study, published in the journal Geology, completely refutes the suggestion of a mid-air explosion. The study said that while neither a mid-air explosion nor a comet impact could melt the desert sand, they found the glass plate contained a rare mineral called reidite, and they say this thing can only be shocked into existence by the force of a collision, which is millions of times. many times more powerful than an airborne explosion. Dr. Cavosie states:
Both meteorite impacts and airborne explosions can cause melting, however, only meteorite impacts create shock waves that form high-pressure minerals, so the finding Previous evidence of reidite confirms it was created by a meteorite impact.
Live Science reports the study said, “airborne explosions create shock waves in the air that can reach thousands of pascals (a unit of pressure), asteroid impacts cause shock waves of thousands billion pascals on the ground.”
Comet Hale-Bopp photographed in the vicinity of Pazin in Istria/Croatia ( CC BY SA 2.0 )
Cometary material has never been found on Earth before except in microscopic dust particles in the upper atmosphere and in Antarctic ice. Space agencies have spent billions of dollars to secure a small amount of pristine comet material and return it to Earth, but Kramers and her team have a new approach to studying this material that no need to go into space to get it.
But what is the importance of this work?
Wits University Professor David Block, a key researcher in Kramer’s team, said: “Comets hold the secrets to unlocking the formation of our solar system and this discovery gives us unprecedented opportunity to directly study cometary material.”
And the consolation that Dr. Cavosie’s team took away was this:
Previous models suggested that the Libyan desert glass represented a large, 100 Mt-level airburst, but our results show that this was not the case. Meteor impacts are catastrophic events, but they are uncommon. Aerial explosions are becoming more frequent, but we now know that we cannot expect a glass-forming event in the Libyan desert in the near future, which may give us some peace of mind.
