Once every thousand years or so carbon-14 production high in the ambiance surges stunningly creating potentially devastating radiation tempest . Astronomers have theories about what could get this , but the most comprehensive subject of these events yet come out to rule all the likely ones out , leaving the causal agent more mysterious than ever .

high-pitched push particles hitting nitrogen atoms in the upper atmosphere produce radioactive carbon-14 – the longest - lived radioactive isotope of carbon copy – which enters the planetary carbon cycle and becomes incorporated in plant life . This mean ancient Sir Herbert Beerbohm Tree rings can reveal the annual history of carbon-14 copiousness going back thousand of years .

explanation have been found for the modest variations in carbon-14 copiousness encounter over the last thousand years , but an immense capitulum in 774 CE was instantly puzzling when discovered a decennium ago . However , a unexampled study collaboration between scientist of many field has been stumped endeavor to identify the crusade of this and similar events .

The 774 carbon-14 spikewas identifiedin Nipponese tree diagram rings by a squad led by physicist Fusa Miyake of Nagoya University in 2012 . It has since been support as a global phenomenon , name in Miyake ’s honor . Similarly - sized global events have been substantiate in 993 CE and 660 , 5259,5410 , and 7176 BCE . Several low events have also been identified , while others continue consider , with conflicting data from different location . Inevitably , the further back in metre you go , the hard it is to obtain accurately dated Sir Herbert Beerbohm Tree ring to conform or rebut such events .

Dr Benjamin Popeof the University of Queensland describes the unexampled study as the most comprehensive investigating of Miyake events yet conducted . However , he acknowledged to IFLScience that it has deepened the whodunit of their cause , rather than explain it .

The first shot about Miyake events was that they were get by enormous solar flares on a scale perhaps ten times theCarrington Eventof 1859 . This would be a very frightening prospect . If the Carrington Event occurred today it would pass over out a large portion of our satellites , cyberspace line , and electricity transmission lines , throwing society into chaos . Something an order of magnitude of magnitude larger is hard to guess .

However , if this is the case , we would anticipate Miyake events to co-occur with solar bike acme . Pope and co - author could n’t find any grounds of that . An alternative explanation is actually the opposite . Solar activity boost the solar wind and helpsshield the Earthfromcosmic rays . Miyake events therefore could constitute abbreviated but extreme solar minima , condense versions of theMaunder Minimum , when sunspot and solar flares vanished .

Pope told IFLScience this remains a opening , but his team could n’t find evidence to substantiate it .

Alternatively , Miyake effect might have nothing to do with the Sun , instead being triggered by supernovas or other cosmic result . Yet no Miyake consequence coincided with any of the love supernovas of the last millenary , ostensibly a destruction blow to that idea . The paper raises the possibility they are have by nearbymagnetarsbut acknowledges we have n’t ascertain one tightlipped enough to Earth to be a plausible culprit .

Although the authors ca n’t explain these outcome , they did learn something of import . At least one Miyake upshot lasted more than a twelvemonth , and others may also have been extended .

“ Rather than a single instantaneous explosion or flare , what we may be looking at is a variety of astrophysical ‘ storm ’ or outburst , ” first writer and undergraduate student Qinyuan Zhang said in astatement .

Pope told IFLScience that ’s probably honorable newsworthiness . “ More spread out and less catastrophic is good for us , although it still could create problem over a prolonged period . ” For Pope , this emphasise the need to translate events that have an almost 1 percentage chance of come in the next ten .

A pre - electrical world would not have been affect by utmost quad weather the way we would today , but we might hope someone notice . Pope say IFLScience that the only ambiguous news report that might bear on to what was find at the time is a reference in the Anglo - Saxon Chronicle to a “ red crucifix after sundown ” in 774 CE . This is the only astronomical event described in the Chronicle . It is broadly thought to pertain toan aurora , but as Pope told IFLScience , “ To a mediaeval monk , everything look like a crucifix , ” determine its modern usefulness .

The theme is published inProceedings of the Royal Society A.