Three case reports on the cometary plasma tail in the historical documents

Abstract

Cometary tails visually manifest the solar wind and became a first hint for its discovery. While the solar wind is being directly monitored with satellites, its time series before the space age has been controversially reconstructed with multiple proxies. Recently, cometary plasma tail observations have been subjected to consideration to indirectly measure the solar wind but brought conclusion that no plasma tail has been reported prior to 1769 probably due to their brightness. However, historical records have occasionally reported comets with two tails even before 1769 and these cases have been tentatively associated with visual reports of cometary plasma and dust tails. Therefore, we examined three such cases (C/1577 V1, 1P/837, and 1P/760), compared the descriptions in historical records with calculated direction of their plasma tails. Our comparisons show that the records and calculations agree in these cases and plasma tails were visually recorded corresponding to these three great comets. These cases certify the capability of plasma tail observations with the unaided eye even before 1769, qualitatively imply their extreme brightness, proximities with the Sun and the Earth, and relative enhancements of UV radiations and interaction of cometary neutral atmosphere with solar wind plasma and magnetic field, while the lack of their detailed length or kink hinders us from their quantitative measuring. Further investigations will probably lead to the re-discovery of even more visual evidence of cometary plasma tail and, hence, improve our understanding on past space climate.

Cometary records revise Eastern Mediterranean chronology around 1240 CE

“…Astronomical phenomena recorded in various past periods all over the world have sometimes been regarded as keys to determining the dates of major historical events that have been associated with these phenomena in historical writings; such phenomena can also be helpful in evaluating the writings themselves, in terms of their chronological accuracies, the periods in which they were written, the places where they were written, and so on (e.g. Walker 1999;Hayakawa et al 2017;Hayakawa et al 2020). In the Byzantine Empire (Late Antiquity until 1453), scholars who inherited ancient Greco-Roman astronomy and astrology maintained the tradition of charting horoscopes and recording notable astronomical phenomena in their writings; they interpreted these phenomena as omens of various future terrestrial events, such as famines, plagues, political crises, and personal life events (Caudano 2020).…”