close proximity of Halley to Earth’s orbit during
the Maya mid-Classic period made a strong
argument for looking for evidence related to its
Eta Aquariid showers, which were recorded by
ancientChineseastronomersasfarbackas74
BCE.
AsherandKinsmanappliedtheLeonidmodel
to simulate meteoroid-sized particles attributed
toCometHalley’spassagesfromasearlyas1404
BCE in order to identify years when meteor
outburstsmighthavebeenseenonEarth.After
validating their approach by post-predicting
observations in the ancient Chinese texts,
they compared the same outburst dates to the
surviving Maya record of notable dates.
Theygot30hits.
“Whilstsomeofthemwillbecoincidences,”
Asheradmits,“therearemanymorematches
in or just after key meteor outbursts than you
would expect to see by chance alone.”
Therecordedeventsthatmostcommonly
corresponded to Eta Aquariid displays were royal accessions,
events that could easily be planned to coincide with or
occur near the date of a meteor shower. For the shower
in CE 531, Kinsman and Asher showed that the intensity
of this burst resulted from Earth encountering particles
released by Comet Halley during three previous passages
(CE295,374and451).Therelativelyrecentdepositionof
detritusbythecometmeanttherehadbeenlittletimefor
dispersion, ensuring densely packed trails that could cause
an intense outburst. The result was a shower Asher believes
would have been spectacular, perhaps even to the extent of
theincredibleLeonidmeteorstormof1833,duringwhich
estimateshavesuggested24,000meteorswereobservable
during an astounding nine-hour display. This celestial
show was described at the time by Yale College Professor
Denison Olmsted as “a constant succession of fire balls,
resembling sky rockets, radiating in all directions from a
point in the heavens,” and if a similar shower had occurred
in clear skies above the Maya city-states, it would have been
impossible to ignore.
The calendar entry for CE 531 might itself provide
additional evidence for a meteor-shower-inspired coronation,STSKY TRACKERSDespite a paucity of records related to
meteor showers that might indicate otherwise, the Maya were
keenobserversofthenightsky.Someoftheirastronomical
knowledge was recorded in the Dresden Codex, a Maya history
andastronomytreatiseinkedonpapermadefromtheinnerbark
of a species of ig.The Venus Table
A large part of the Dresden Codex,
the oldest and the best preserved
Maya manuscript, is dedicated
to astronomical and calendrical
data. These data include solar and
lunar eclipse predictions based on
observable lunar phases, as well
as tables for tracking the cycles of
Venus, Mars and Mercury.Six pages of the Dresden Codex are
dedicated to the observable phases
of Venus, beginning with the folio
shown here. Credit for deciphering
the so-called Venus Table goes
to Ernst Förstermann, director of
the Royal Library (now the Saxon
State Library), who in 1901 worked out that the
numbers inked in red across several pages of the
codex were identical, and that they added up to- Recognising that this number was almost
identical to the synodic period of Venus (583.92
days, the time it takes for Venus to return to the
same position as seen from Earth), Förstermann
determined that the red numbers — 236, 90,
250 and 8 — marked four significant points in
the planet’s cycle: its morning heliacal rising; its
disappearance at superior conjunction; its irst
evening rise; and its disappearance at inferior
conjunction. S. N. JOHNSON-ROEHR
CODEX: SLUB / CC BY-SA 3.0
http://www.skyandtelescope.com.au 39