Comets, Meteors and Aurorae

Occasionally, cuneiform sources contain references to transient celestial phenomena such as comets (sallammû), meteors or the aurora borealis.

Classical sources suggest that some Babylonian astronomers believed that comets, like the planets, moved in fixed orbits and made periodic appearances. Around AD 63, the Roman philosopher Lucius Annaeus Seneca wrote:

“Apollonius of Myndos says that the Chaldaeans place comets in the category of planets and have determined their orbits; Epigenes, on the contrary, says that the Chaldaeans have no understanding of comets but that to them comets seem to be on fire from some sort of turbulence in aroused and twisted atmosphere” (Naturales quaestiones VII 4.1).

The following passage in the Babylonian Talmud has been quoted by some as evidence that Jewish rabbi’s may have been aware of the periodical nature of comets:

[R. Gamaliel II and R. Joshua b. Hananiah] once travelled on board a ship. R. Gamaliel had with him some bread only, while R. Joshua had with him bread and flour. When R. Gamaliel’s bread was consumed he depended on R. Joshua's flour. ‘Did you know’, the former asked him, ‘that we should be so much delayed that you brought flour with you?’ The latter answered him, ‘A certain star rises once in seventy years and leads the sailors astray, and I suspected it might rise and lead us astray.’ (Horayoth 10a).

Comets

Meteors, Meteorites and the Aurora Borealis

Catalogues of Cometary Observations and Orbits

Ancient Observations and Orbital Motion of Comet 1P/Halley

Of all cometary orbits, that of Halley’s Comet is one of the best known. Each return since 240 BC has been observed from Earth and the returns of 164 BC and 87 BC have also been recorded in cuneiform sources.

Several investigations have been published linking the orbit of Halley’s Comet with Chinese observations before 240 BC but earlier returns have not been confirmed due to the lack of reliable observations. As the orbit of Halley’s Comet is influenced by non-gravitational forces, numerical integrations of its orbit become increasingly unreliable as one recedes further back in the 1st millennium BC.

The following table lists the dates of perihelion passage of Comet 1P/Halley as calculated by various astronomers in the past. The dates of perihelion passage are expressed in the YEAR/MONTH/DAY format. The year is given in astronomical notation, i.e. –11 is equivalent with 12 BCE, etc.

  Cowell &
Crommelin
(1908)		 Viliew
(1917)		 Kamiènski
(1961)		 Chang
(1978)		 Yeomans
& Kiang
(1981)		 Brady
(1982)		 Landgraf
(1986)		 Sitarski
(1988)
1 –11/10/08 –10.23 –10.23 –11/09/27 –11/10/10 –11/10/08 –11/10/08 –11/10/08
2 –86/08/15 –85.42 –85.42 –86/08/15 –86/08/06 –86/07/10 –86/08/05 –86/08/03
3 –162/05/20 –161.71 –161.71 –162/01/20 –163/11/12 –163/06/22 –163/11/08 –163/10/23
4 [–239/05/15] –238.04 –238.04 –239/08/02 –239/05/25 –240/11/30 –239/05/24 –239/03/22
5   –312.70 –312.70 –314/12/06 –314/09/08 –316/10/15 –314/09/09 –314/02/13
6   –389.70 –389.70 –390/12/08 –390/09/14 –392/04/22 –390/09/15 –391/12/15
7   –465.73 –465.73 –465/09/02 –465/07/18 –467/07/16 –465/07/17 –466/12/02
8   –543.95 –543.95 –539/11/01 –539/05/10 –543/04/10   –542/04/13
9   –621.04 –621.04 –614/07/01 –615/07/28 –619/10/05   –619/10/16
10     –700.1 –689/12/20 –689/01/22 –693/11/01   –694/12/04
11     –777.2 –761/01/11 –762/08/05 –768/05/13   –770/10/10
12     –855.6 –833/03/12 –835/05/09 –844/12/29   –845/05/26
13     –931.8 –907/06/27 –910/05/20 –917/10/31   –922/08/06
14     –1008.9 –982/08/17 –985/12/02 –992/03/15   –999/10/13
15     –1084.3 –1056/03/07 –1058/12/03 –1068/07/13   –1074/01/22
16     –1161.3   –1128/04/03 –1142/04/15   –1151/07/09

Possible Early Returns of other Periodic Comets

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