Astronomers unravel a mystery of the Dark Ages

EurekAlert ^ | 3-Feb-2004 | Dr Derek Ward-Thompson

[ckilmer]

Public release date: 3-Feb-2004

Contact: Dr Derek Ward-Thompson derek.ward-thompson@astro.cf.ac.uk 029-2087-5314 Cardiff University

Astronomers unravel a mystery of the Dark Ages Undergraduates' work blames comet for 6th-century "nuclear winter" Scientists at Cardiff University, UK, believe they have discovered the cause of crop failures and summer frosts some 1,500 years ago – a comet colliding with Earth. The team has been studying evidence from tree rings, which suggests that the Earth underwent a series of very cold summers around 536-540 AD, indicating an effect rather like a nuclear winter.

The scientists in the School of Physics and Astronomy believe this was caused by a comet hitting the earth and exploding in the upper atmosphere. The debris from this giant explosion was such that it enveloped the earth in soot and ash, blocking out the sunlight and causing the very cold weather.

This effect is known as a plume and is similar to that which was seen when comet Shoemaker-Levy-9 hit Jupiter in 1995.

Historical references from this period - known as the Dark Ages – are sparse, but what records there are, tell of crop failures and summer frosts.

The work was carried out by two Cardiff undergraduate students, Emma Rigby and Mel Symonds, as part of their student project work under the supervision of Dr Derek Ward-Thompson.

Their findings are reported in the February issue of Astronomy and Geophysics, the in-house magazine of the Royal Astronomical Society.

The surprising result of the new work is just how small a comet is needed to cause such dramatic effects. The scientists calculate that a comet not much more than half a kilometre across could cause a global nuclear winter effect. This is significantly smaller than was previously thought.

Dr. Ward-Thompson said: "One of the exciting aspects of this work is that we have re-classified the size of comet that represents a global threat. This work shows that even a comet of only half a kilometre in size could have global consequences. Previously nothing less than a kilometre across was counted as a global threat. If such an event happened again today, then once again a large fraction of the earth's population could face starvation."

The comet impact caused crop failures and wide-spread starvation among the sixth century population. The timing coincides with the Justinian Plague, widely believed to be the first appearance of the Black Death in Europe. It is possible that the plague was so rampant and took hold so quickly because the population was already weakened by starvation.

[Sam Cree]

I think you have referenced this, haven't you, blam?

[Molly Pitcher]

Have you seen this theory?

[farmfriend]

I thought it was a massive volcano eruption.

[pabianice]

Big deal. Anyone who watches "Stargate SG-1" knows this.

[ClearCase_guy]

The book "Catastophe" by David Keys is quite interesting. He blames it on a volcano. Whatever, it sure seems like something effected the climate and civilizations around the globe at around 536 AD.

[Fitzcarraldo]

If there was this much dust in the atmosphere and it settled out there should be a soil layer that can be analyzed. Problem is where is the best place to look.

[WayneM]

I thought a large, alcohol-filled Kennedy relative fell into a bog and cased a massive release of swamp gas.

[Muleteam1]

Without evidence of deposition from the comet's ash that corresponds to the timing of the Dark Ages, it seems like a huge leap in logic to go from evidence of cool summers, crop losses, and plague to a comet exploding in the earth's atmosphere.

Muleteam1

[Dog]

Thanks ...very interesting.

[farmfriend]

I like that one.

[blam]

It was a comet that plunged into the Celtic Sea. Mike Baillie should be credited with this discovery.

The Dark Ages, Were Thay Darker Than We Imagined?

"Concluding Thoughts Ben Rudder, an anthropologist who reviewed in New Scientist magazine a recently published book by Baillie on the subject, wrote :"

"If Baillie is right, history has overlooked probably the single most important explanation for the intermittent progress of civilisation."

[The Great RJ]

No, no it was Republicans and SUV's that caused this climate disaster--Al Gore told me so.

[blam]

Catastrophic Event Preceded Dark Ages - Scientist

[LibWhacker]

Here's an interesting post that explains some of that logic. In some cases, ancient scribes wrote about the effects they witnessed firsthand. And the tree ring data testifies to how widespread the effects were.

[Mr. Lucky]

My kids' bedroom.

[blam]

"The book "Catastophe" by David Keys is quite interesting. He blames it on a volcano. Whatever, it sure seems like something effected the climate and civilizations around the globe at around 536 AD."

I read that book. I think a better book on the subject is Mike Baillie's, Exodus To Arthur

Baillie has captured a number of worldwide events in the 10,000 year tree ring record.

[blam]

Did Asteroid And Comets Turn The Tide Of Civilization?

[farmfriend]

Gods, Graves, Glyphs
List for articles regarding early civilizations , life of all forms, - dinosaurs - etc.

Let me know if you wish to be added or removed from this ping list.

[LibWhacker]

You have to wonder how well modern civilization would stand up to something like that today. If the bollide were large enough, then obviously, no. But would we cave under exactly the same pressure that did in the ancients? Personally, I think not. We would understand what was happening to us and if we could maintain our infrastructure, we could weather the famine and plague. But let's not test it, okay? :-) Earth probably really does need a space shield.