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A brooch owned by Tutankhamun.

A brooch owned by Tutankhamun. Photograph courtesy Jon Bodsworth via University of the Witwatersrand

Andrew Fazekas

National Geographic

Published October 11, 2013

Saharan glass and a brooch belonging to King Tut provide the first evidence of a comet directly impacting Earth, a new study claims. The finding may help unlock some of the mysteries surrounding the birth of our solar system.

About 28 million years ago a comet exploded over Egypt, creating a 3600°F (2000°C) blast wave that spread out over the desert below. The fiery shockwave melted the sand, forming copious amounts of yellow silica glass scattered over 2,300 square miles (6,000 square kilometers) of the Sahara.

Polished into the shape of a scarab beetle, a large piece of this glass found its way into a brooch owned by the famed Egyptian boy king Tutankhamen.

"Because there is no sign of an impact crater, it has been a mystery as to what kind of celestial event actually could have caused this debris field, but a small, black stone found lying in the middle of the glass area caught our attention," said study co-author David Block, an astronomer at Wits University in Johannesburg, South Africa.

Saharan Surprise

A tiny slice of the black pebble was put through isotopic analysis, which definitely ruled out that it came from a meteor. Instead, the analysis showed that the pebble possessed the unique chemical signature of a comet, measured in terms of elements such as argon and carbon.

"It was then basically a matter of running the movie backwards in time and predicting what temperatures were needed to create the conditions we find that make up the fragment today," Block says. "So when I saw the result of the analyses, I was completely ecstatic to realize that such a piece of cosmic history has been found for the first time right on our doorstep."

While meteors are known to enter the Earth's atmosphere frequently—one can be seen as a shooting star every 15 minutes or so on any random night—not so with comets.

The implosions of comets in planetary atmospheres are exceedingly rare events—the only other definitive case of a comet hitting a planet was back in 1994 when comet Shoemaker-Levy 9 impacted Jupiter's atmosphere.

Astronomical Odds Inspire Caution

And it's because of this rarity that Earth scientist Andrew Glikson of the Australian National University in Canberra, who was not involved in this study, questions if these yellow glass objects, called tektites, might instead have been created through much more common meteoric events, as seen at many impact sites around the world.

"Why can't the material represent a large tektite formed by heating and melting of sand at the Earth's surface by an asteroid impact, such as, for example, the Australite tektites?" asks Glikson.

While this extraterrestrial glass is considered common around many impact sites,  geologist Gerald Johnson, who was not involved in the study, says that beyond the compelling evidence the team presents in their chemical workup of the black pebble, it's not surprising that the research community may be wary of these results.

"A comet, mostly water, vaporizes in the atmosphere and leaves little for the geologic record, while the 'dirt' incorporated in the comet also is disseminated widely and is unlikely to be found because of impact dispersal, surface weathering, and erosion," said Johnson, a meteor impact researcher at the College of William and Mary in Williamsburg, Virginia.

"Undoubtedly, the Earth has been hit numerous times by comets, but our knowledge of these is lacking because comets leave such a poor record ... so this discovery is amazing."

Solar System Origins

Microscopic dust particles from these icy interlopers have been collected from the upper atmosphere and from Antarctic ice, and have been scooped up by space probes.

But having a chance to study sizable comet material firsthand would be exceptional, and Block and his team believe it can offer a unique chance to study the birth of our solar system.

Cosmic particles called presolar grains formed in the stellar cloud of gas and dust that gave birth to our solar system, and are thought to have remained within comets and meteors.

"My bet is that this little rock will unlock some unique secrets in time to come, specifically because it appears packed with presolar grains," said Block.

The comet study will be published in an upcoming issue of Earth and Planetary Science Letters.

Follow Andrew Fazekas, the Night Sky Guy, on Twitter and Facebook.

kevn curran
kevn curran

It my may be an interesting coincidence that the silica glass is featured in the brooch.  However, the Egyptians venerated a stone called the Benben Stone in Heliopolis.  The Benben Stone, based on descriptions of the object, sounds like a recovered meteorite. 

I've been studying this subject for years and have come to believe that the Egyptians were very familiar with periodic comets and Kreutz Sungrazers (the progenitor); they simply referred to a comet as a specific god, goddess, or monster.  If the Egyptians were able to recognize the return/beginning of a decan (a decan is the division of the sky into 36 ten-degree sections) before sunrise by at least the 22nd century BCE, why wouldn't they track a comet's unusual movement against the stars they knew so well?  They were every bit as smart is us, so what did they think a comet was?

We haven't lost our ancestors' knowledge of comets. We've misinterpreted their stories or dismissed them as fiction because they refer to gods or monsters...and don't use a word the Greeks invented - kometes.  Ancient comet observation and worship is a subject I've been interested in years. I truly believe that our ancestors' worship, and respect, for comets is the result of multiple impacts in human history (the past 200,000 years). Several religious texts or oral traditions around the world allude to these impacts.

In 2007, a team of scientists led by Allen West and Richard Firestone presented evidence that a massive comet struck around the Great Lakes around 10850 BCE.  What did that impact look like?  What was the aftermath?

For more information on this impact and other recent impacts in human history check out

Abdel Carrillo
Abdel Carrillo

me fascina la pagina de National Geographic.

es la primera vez que accseso

Aaron Musa
Aaron Musa

Please could someone tell me when was day one. Which I believe should be the beginning of energy and what is the time interval between the origin of energy and the first material .

Franc Retief
Franc Retief

When a scientist like David Block believes in God, we should take his findings with a pinch of salt.   

Franc Retief
Franc Retief

When a scientist like David Block believes in God, he can believe anything.  We must take his results with a pinch of salt.

Brent Rollens
Brent Rollens

Apparently some find the mere act of proposing a hypothesis to be offensive.

Bill Graham
Bill Graham

No assumptions are being made in the article. They ran the pebble through some tests. They ruled out a meteor. They found the signature elements of a comet: "measured in terms of elements such as argon and carbon." That doesn't mean they assume it's a comet. In fact, they're only saying it's evidence of a comet. The way this article is written carefully navigates the potential issues people might raise if they carelessly said it was proof of a comet.

What are you people afraid of? Do you fear the fact that the earth is 4.5 billion years old? That IS a fact. We have proof of that. 28 million years ago is like tiny blip on the radar compared to the age of our planet. Why are you so afraid to admit that a comet hit the earth? What about that frightens you so much that  you have to attack the writer of this article with what appears to be an combination of ad hominem and straw man arguments?

Meteors strike the earth every day. In fact, every minute and every hour of the day, something falls to the earth from outer space. I don't see why a comet slamming into the earth is so impossible to believe. Many scientists believe our water supply came from comets. What is the problem here? Are you people strict, literal six-day creationists? If that's the case, not even the Bible really supports your point of view. Look at Genesis 1:1-2:3. Then, read Genesis 2:4-2:25. Read it all very carefully.

Do a little research into the original language if you dare. Start with Genesis 1:1 with a solid Hebrew translation, mechanical and otherwise. Then, ask yourself one question. What did God mean when he told Adam that he would die the day he ate the fruit from the tree of knowledge of good and evil. Look at all the occurrences of the Hebrew word "Yom" in the Hebrew canon. Let it sink in that it does not always equal a solar period of 24 hours. You who think you know the Bible so well know practically nothing of it.

John E. Butler
John E. Butler

A lot of assumptions are riding on a pebble.  A pebble which could have arrived at its destination in a dozen different ways.

El Gabilon
El Gabilon

This study seems to be assumptions with no real evidence of a large crater in Egypt.  Fish have been known to fall out of the sky in desert areas and there is no reason not to suspect that this "pebble"  may have been carried by atmospheric conditions  to its place of discovery. What we have is a black pebble that may have come from a comet and if it did the comet may have landed elsewhere, while the pebble may have even fallen before the comet hit.  Are there not "sand storms" occuring in Egypt? Perhaps before publishing papers conclusive evidence should be required.  The old "publish or perish" still applies even in the 21st century.  Although scientists should be free to investigate controls should be administered to prevent excessive speculation.

Seth Forbis
Seth Forbis

yet another scientist grasping at straws for headlines in the hopes of making more grant money...

a Micklea
a Micklea Sahara region was a desert 28 MILLION years ago?

Betty Cooper-Ritchey
Betty Cooper-Ritchey

It is amazing that in our day and time, these things are being discovered.  It is really true, I believe that we are all one world, and no doubt in my mind, that we will find evidence of more events like this.

Augie Gos
Augie Gos

@Jonathan Cato it began when we realized we could count it OR if theories are correct it began at the Big Bang which is 13 billion years ago

Valerie Pole
Valerie Pole

@Franc Retief What a ridiculous comment. Use science to address the issue or discovery and verify or disprove it rather than a personal attack on the scientist's religious belief: Whether Jew, Muslim or Christian.

Fleck Kcelf
Fleck Kcelf

@Franc Retief Yeah, and when scientist believes that we came from a rock - he can't believe anything! :D your thinking is so cheap!

David Murray
David Murray

@Bill Graham If the good people of our world would use simple known facts to dispel there practiced teaching  we would be in a better world now.  If I can hold a stone in my hand and have it carbon dated to be 65 million years old, cut it open and discover a fossilized fossil that tells me the creator of our everything wasn't done in six days.  

Love your remarks



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