The space environment before the space age

Barnard, Luke; Owens, Mat; Scott, Chris J.

doi:10.1093/astrogeo/atx056

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…Finally, we must stress that absence of evidence is not evidence of absence due to the fragmentary nature of historical records in the 8th century (e.g. Silverman, 1992;S15;Barnard et al, 2017). Moreover, SEP events are not necessarily followed by great auroral displays, as the relationship between GLEs coming from SEP events and magnetic storms caused by CMEs with southward IMF is far from straightforward (e.g., Gopalswamy et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, it is important to reconsider the physical nature of this celestial sign to understand the background solar activity around 774/775. The initial difficulty is partially caused by the rather fragmentary nature and limited amount of information on historical records in this period (Silverman, 1992(Silverman, , 1998Barnard et al, 2017). In this sense, it is always important to analyze the given records in comparison with philological results based on the original records, and parallel cases of visual observations in early-modern times, to derive reasonable conclusions, as is also done for the reconstruction of the amplitude of the Maunder Minimum (Zolotova and Ponyavin, 2015;Vaquero et al, 2015), the reliability of sunspot drawings (Zolotova and Ponyavin, 2015;Usoskin et al, 2015;Carrasco, Álvarez, and Vaquero, 2015;Carrasco, Vaquero, and Gallego, 2018), the reliability of auroral records at that time (Zolotova and Ponyavin, 2016;Usoskin et al, 2017), and intensity of magnetic storms in the 19 --20 centuries (Silverman and Cliver, 2001;Cliver and Dietrich, 2013;Silverman, 2008;Hayakawa et al, 2018f).…”

Section: Introductionmentioning

confidence: 99%

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The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity

et al. 2019

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The anomalous concentration of radiocarbon in 774/775 attracted intense discussion on its origin, including the possible extreme solar event(s) exceeding any events in observational history.Anticipating such extreme solar events, auroral records were also surveyed in historical documents and those including the red celestial sign after sunset in the Anglo-Saxon Chronicle (ASC) were subjected to consideration. Usoskin et al. (2013, Astron. Astrophys. 55, L3: U13) interpreted this record as an aurora and suggested enhanced solar activity around 774/775. Conversely, Neuhäuser and Neuhäuser (2015a, 2015b, Astron. Nachr. 336, 225; 336, 913: N15a and N15b) interpreted "after sunset" as during sunset or twilight; they considered this sign as a halo display and suggested a solar minimum around 774. However, so far these records have not been discussed in comparison with eyewitness auroral records during the known extreme space-weather events, although they were discussed in relationship with potential extreme events in 774/775. Therefore, we reconstruct the observational details based on the original records in the ASC and philological references, compare them with eyewitness auroral observations during known extreme space-weather events, and consider contemporary solar activity. We clarify the observation was indeed "after sunset", reject the solar halo hypothesis, define the observational time span between 25 March 775 and 25 December 777, and note that the parallel "drawing of lunar halo display" in 806 in the ASC shown in N15b was not based on the original observation in England. We show examples of eyewitness auroral observations during twilight in known space-weather events, and this celestial sign does not contradict the observational evidence. Accordingly, we consider this event happened after the onset of the event in 774/775, but shows relatively enhanced solar activity, with other historical auroral records in the mid-770s, as also confirmed by the Be data from ice cores.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity

et al. 2019

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“…As we look further into the past, particularly prior to the space age, reliable records of space weather events become harder to obtain (Barnard et al, 2017). Furthermore, the past development of observatories and instrumentation often means that it is not possible to obtain homogeneous quantitative records of space weather occurrence over long time periods.…”

Section: Historical Space Weathermentioning

confidence: 99%

“…Three well established proxies are found in sunspot observations, geomagnetic activity records, and the concentrations of cosmogenic radionuclides stored in natural archives (Owens et al, 2016a,b). These estimates of historical solar variability are invaluable for placing the comprehensive space-age solar observations in a proper context (Barnard et al, 2017), and for investigating plausible scenarios of future space climate change (Abreu et al, 2008;Steinhilber et al, 2012;Matthes et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

What can the annual ¹⁰Be solar activity reconstructions tell us about historic space weather?

Barnard

McCracken²,

Owens

et al. 2018

J. Space Weather Space Clim.

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-Context: Cosmogenic isotopes provide useful estimates of past solar magnetic activity, constraining past space climate with reasonable uncertainty. Much less is known about past space weather conditions. Recent advances in the analysis of 10 Be by McCracken & Beer (2015, Sol Phys 290: 305-3069) (MB15) suggest that annually resolved 10 Be can be significantly affected by solar energetic particle (SEP) fluxes. This poses a problem, and presents an opportunity, as the accurate quantification of past solar magnetic activity requires the SEP effects to be determined and isolated, whilst doing so might provide a valuable record of past SEP fluxes. Aims: We compare the MB15 reconstruction of the heliospheric magnetic field (HMF), with two independent estimates of the HMF derived from sunspot records and geomagnetic variability. We aim to quantify the differences between the HMF reconstructions, and speculate on the origin of these differences. We test whether the differences between the reconstructions appear to depend on known significant space weather events. Methods: We analyse the distributions of the differences between the HMF reconstructions. We consider how the differences vary as a function of solar cycle phase, and, using a Kolmogorov-Smirnov test, we compare the distributions under the two conditions of whether or not large space weather events were known to have occurred. Results: We find that the MB15 reconstructions are generally marginally smaller in magnitude than the sunspot and geomagnetic HMF reconstructions. This bias varies as a function of solar cycle phase, and is largest in the declining phase of the solar cycle. We find that MB15's excision of the years with very large ground level enhancement (GLE) improves the agreement of the 10 Be HMF estimate with the sunspot and geomagnetic reconstructions. We find no statistical evidence that GLEs, in general, affect the MB15 reconstruction, but this analysis is limited by having too few samples. We do find evidence that the MB15 reconstructions appear statistically different in years with great geomagnetic storms.

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Atomic Radiation in Dense Magnetized Plasma

Leng

Chen

2021

Few-Body Syst

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The space environment before the space age

Cited by 3 publications

References 17 publications

The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity

The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity

What can the annual ¹⁰Be solar activity reconstructions tell us about historic space weather?

Atomic Radiation in Dense Magnetized Plasma

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The space environment before the space age

Cited by 3 publications

References 17 publications

The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity

The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity

What can the annual 10Be solar activity reconstructions tell us about historic space weather?

Atomic Radiation in Dense Magnetized Plasma

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What can the annual ¹⁰Be solar activity reconstructions tell us about historic space weather?