Radiocarbon around the Carrington event

Abstract

The Sun is a volatile and complex body, understanding its behaviour is key to the continued operation of modern technology. The Carrington event was a violent white light event and generally believed to have lead to one of the largest solar storms in modern human history. However the event has not been seen clearly in the 14C records analysed in other publications. Here we investigate the Carrington event specifically using the cellulose extracted from tree rings. It was found that there is possible manifestation of the event in the form of an increase in ∆14C of 5 ± 2‰ between 1859 and 1860. This in a noticeable increase but is preceded by a significant decrease for the year ∆14C 1859. The reason for this decrease is unclear and could be due to errors in the experiment itself or an actual manifestation of previously unnoticed solar activity. More data would need to be collected to confirm and investigate the results found in this preliminary study.

Popular Abstract

Throughout time, man has always had a fascination with the sun. It is the singular most important reason there is life on this planet. Yet this volatile giant varies in activity, it can be very quiet, and can sometimes exhibit explosive behaviour. One such event is the Carrington event, observed on the 1st of September 1859 by Richard Carrington. An intense brightening was observed around a sunspot, which in simple terms is a region of highly varying magnetic field. The resulting activity caused a coronal mass ejection, a jet of plasma that travels towards earth and wreaks havoc on the geomagnetic field. This can completely destroy electronic circuitry such as the ones in satellites. This creates a clear danger to our telecommunication network and any other service that requires orbiting satellites. So how do we find and predict such an event. The answer is we can use radioactively decaying material in trees or ice.
These are called radionuclides. When these storms strike the earth, they create an excess of these radionuclides that are then deposited in records such as the trees and ice mentioned earlier. The material then decays, but this excess is still recorded. In this experiment the 14C record in annual tree rings from 1856 to 1864 was used to find whether the Carrington event can be seen. This required collecting wood shavings from each of the individual years, extracting the cellulose, then using a machine to turn it into graphite. The amount of 14C was then found using an special type of accelerator called an accelerator mass spectrometer. A graph was then produced. It shows the ratio of 14C/12C, in simple terms this ratio tells us about how active the sun was at the time. An increase is indeed observed, for 1860 (the year of interest as the storm occurred in late 1859, meaning it would appear in the tree ring for 1860). However a large decrease is observed for 1859, this was not expected. It could obviously be due to an error in the experiment, or more worryingly a previously unnoticed manifestation of solar activity. This was only a preliminary study, other publications have indeed not seen any manifestation of the Carrington event. Ultimately more research would need to be undertaken, yet every step that we take leads to a better understanding of the volatile giant.

• author: Pierce, Damien
• supervisor: Raimund Muscheler; Florian Adolphi; Kristina Stenström
• organization: Nuclear physics; Department of Physics
• course: FYSK02 20161
• year: 2016
• type: M2 - Bachelor Degree
• subject: Physics and Astronomy
• language: English
• id: 8878823
• date added to LUP: 2016-06-14 09:02:54
• date last changed: 2016-11-15 14:04:38