Cataclysm No More: New Views on the Timing and Delivery of Lunar Impactors

If properly interpreted, the impact record of the Moon, Earth’s nearest neighbour, can be used to gain insights into how the Earth has been influenced by impacting events since its formation ~4.5 billion years (Ga) ago. However, the nature and timing of the lunar impactors – and indeed the lunar impact record itself – are not well understood. Of particular interest are the ages of lunar impact basins and what they tell us about the proposed “lunar cataclysm” and/or the late heavy bombardment (LHB), and how this impact episode may have affected early life on Earth or other planets. Investigations of the lunar impactor population over time have been undertaken and include analyses of orbital data and images; lunar, terrestrial, and other planetary sample data; and dynamical modelling. Here, the existing information regarding the nature of the lunar impact record is reviewed and new interpretations are presented. Importantly, it is demonstrated that most evidence supports a prolonged lunar (and thus, terrestrial) bombardment from ~4.2 to 3.4 Ga and not a cataclysmic spike at ~3.9 Ga. Implications for the conditions required for the origin of life are addressed.     

Compounds of the organogenic elements in Apollo 11 and 12 lunar samples: A review

Investigations of low molecular weight compounds of the organogenic elements on lunar samples are reviewed. The three general techniques of vacuum pyrolysis, acid hydrolysis, and crushing have been employed by most investigators. Vacuum pyrolysis of lunar fines produce a variety of gaseous species which are either: (1) indigenous, (2) solar wind products and/or (3) chemical reaction products of mineral phases found in the lunar samples. Acid hydrolysis of lunar fines using deuteriumlabeled acids yields evidence for indigenous methane and ethane. Methane and ethane found in the lunar fines are largely derived from the solar wind with only trace amounts indigenous to the samples. Crushing experiments with lunar fines and breccias produce methane, ethane, hydrogen, nitrogen, hydrogen sulfide and the rare gases.     

Review of methods used in lunar organic analysis: Extraction and hydrolysis techniques

Extraction, hydrolysis and crushing procedures have proven useful in analyzing for some of the carbon-containing compounds which are present in Apollo 11 and 12 lunar samples. Three main extraction methods employed with aqueous and nonaqueous solvents were refluxing in open and closed systems, Soxhlet extraction, and sonication. With water and acids, refluxing was the method of choice. Of the various nonaqueous solvent systems used, benzene: methanol mixtures were most often selected, and sonication was favored over Soxhlet extraction. Extraction of lunar samples with water followed by acid hydrolysis of the water extract was found to be superior to direct acid hydrolysis of lunar material in the search for amino acids or their precursors. Direct acid hydrolysis of lunar materials did demonstrate however, that carbides or carbide-like compounds are present on the moon. Hydrolysis with deuterated acids and bases showed that lunar samples contain indigenous methane and ethane and confirmed the presence of carbide-like materials. Crushing experiments also showed that gaseous hydrocarbons can be released from lunar samples.     

Lunar cycle and psychiatric hospital admissions for schizophrenia: new findings from Henan province,China

ABSTRACT

Objective: Findings on the effect of the lunar cycle on mental illness are conflicting. We investigated the association between the lunar cycle and a number of psychiatric presentations of schizophrenia and determined which subtypes were susceptible to lunar phases.

Methods: We evaluated 13,067 patients admitted to Zhumadian Psychiatric Hospital between January 1, 2012, and December 31, 2017 (73 lunar cycles). Patients were retrospectively assigned to lunar phase based on their admission date: new moon +/? 1 day, first quarter +/? 1 day, full moon +/? 1 day, and third quarter +/? 1 day. The International Statistical Classification of Diseases, 10th revision (ICD-10), was used for diagnosis. We used a Chi-squared goodness of fit test to evaluate the distribution of admissions across the lunar phase and R*C Chi-squared tests to compare age, sex, birth season, and clinical subtype distributions by phase. We used multiple logistic regression to further identify the relationship between clinical subtype and lunar phase.

Results: Psychiatric admissions for schizophrenia varied significantly across the lunar cycle (χ² = 36.400, p< .0001), peaking in the first quarter, followed by the full moon, and lowest at the new moon. Using unspecified schizophrenia (F20.9) as reference, people with paranoid schizophrenia (F20.0) were more likely to be admitted in the full moon than in other phases (odds ratio: 1.157, 95% confidence interval: 1.040–1.286) (p < .05); other subtypes showed no admission differences during the four lunar phases (p > .05).

Conclusions: Psychiatric admissions for schizophrenia show lunar periodicities. People with schizophrenia tend to be stable in the new moon, but their condition is easily aggravated during the first quarter and full moon. Patients with paranoid schizophrenia are more susceptible to deterioration at the full moon, so merit more attention and care from communities, families, and hospitals.     

Lunar carbon chemistry: Relations to and implications for terrestrial organic geochemistry

The effort expended on the study of lunar carbon chemistry by a sizeable section of the organic geochemical community has resulted in a temporary dislocation in the research output in organic geochemistry. However the long-term beneficial effects of the lunar studies are already obvious in the new and improved methodology, control of contamination, and renewed interest in the characterisation, quantitation and significance of low molecular weight carbon compounds, polymers and inorganic forms of carbon. The role of carbon at the lunar surface is evidently a complex one, the understanding of which should lead to important generalisations for planetary processes.     

Timing of mass spawning in corals: potential influence of the coincidence of lunar factors and associated changes in atmospheric pressure from northern and southern hemisphere case studies

Synchronised multispecies mass spawning events are striking features of reproduction in corals. This synchronous gamete release of thousands of animals over vast stretches of reef is thought to be cued by rhythms of the Moon. However, the mechanisms are not fully understood. We propose an explanation that may contribute to understanding this mechanism, that spawning is triggered by the coincidence of two factors, each in different lunar rhythms. We investigate this proposal in case studies using seven years of coral spawning data from two locations: Kochi, Japan and Lizard Island, Australia. Our calculations show that a feature in a lunar synodic rhythm (the third quarter) will synchronise with a feature in a lunar non-synodic rhythm (the zero declination) usually once, although occasionally twice in a year. Supported by data on the date of spawning from the two locations, we suggest that this coincidence of lunar factors exerts an important influence on the timing of annual mass spawning in corals. This coincidence may be associated with low atmospheric pressure. Spawning at the time of the third lunar quarter may favour fertilisation success due to the reduced currents during neap tides associated with the lower gravitational pressure of the lunar quarters.     

Moon orientation in adult and young sandhoppers

In the last 30 years, lunar orientation has received little attention from students of animal orientation. Even in Talitrus saltator, the first animals in which the lunar compass was demonstrated, research did not continue. Our studies have demonstrated that: 1) chronometrically compensated lunar orientation is independent of the earth's magnetic field (an ever present non-chronometric orientation reference); 2) lunar orientation is independent of the lunar shape; and 3) the lunar compass is also used by young animals born in the laboratory (without experience in nature). Accepted: 30 September 1998     

Lunar rhythms in the deep sea: evidence from the reproductive periodicity of several marine invertebrates

While lunar rhythms are commonly documented in plants and animals living in terrestrial and shallow-water environments, deep-sea organisms have essentially been overlooked in that respect. This report describes evidence of lunar periodicity in the reproduction of 6 deep-sea species belonging to 2 phyla. Occurrences of gamete release in free spawners and larval release in brooders exhibited significant peaks around the new and full moons, respectively. The exact nature of this lunar period (endogenous or exogenous rhythm) and its adaptive significance in the deep sea remain elusive. Current knowledge suggests that proxies of moon phases at depth may include fluxes in particulate matter deposition, cyclic currents, and moonlight for species living in the disphotic zone.     

Ungulate: vehicle collision rates are associated with the phase of the moon

The phase of the moon can affect activity patterns of nocturnal animals, and may also affect visibility for motorists. However, surprisingly little is known about whether the risk of a wildlife-vehicle collision (WVC) is associated with lunar phase. We investigated the relationship between frequency of WVC at night and lunar phase for four large ungulate species that account for a high proportion of serious WVC along roads in agricultural and forested landscapes of two continents: wild boar Sus scrofa, roe deer Capreolus capreolus, and red deer Cervus elaphus in Castile and Leon, Spain, and white-tailed deer Odocoileus virginianus in New York State, USA. Three of the four species most frequently collided with vehicles at night during the full moon phase of the lunar cycle; this pattern was evident throughout the year but was stronger during some months. For roe deer, the species for which WVC was most closely associated with the lunar cycle, the frequency of WVC was 71.3% greater during the full than new moon period. Our results indicate that rates of ungulate WVC at night cycle on a period of a lunar month, which has implications for traffic safety planning and for motor vehicle collision emergency response preparation.     

Lunar Effect on Thoroughbred Mare Fertility: An Analysis of 14 Years of Data, 1986-1999

It became possible to access the yearly studbooks of a major UK Thoroughbred studfarm. By comparing these with subsequent published records of horse-breeding, one could compare the coverings between mares and stallions with the outcome as to whether or not a registered conception occurred. The coverings went on seven days a week with no interruption, over the breeding months of early spring and summer, and so offered an opportunity to test hypotheses concerning the lunar phase cycle. Since the studbooks began, vets have been able to detect the onset of estrus every three weeks, so that the covering dates give a fairly unerring record of mare estrus. Two logically distinct parameters were here tested: the extent to which the onset of estrus was related to the lunar month, and then whether the proportion of successful coverings varied with the lunar month.

A total of 14 successive years of studbook data was recorded and tested in this manner, partly to average out irregularities in lunar angular speed resulting from the apogee-perigee cycle (linked to the 9-year apse cycle) and partly to be able to investigate whether the 18.6-year nutation cycle would affect the way in which the lunar-month cycle worked. This notion came from geomagnetic surveys, which have showed a sizeable modulation of the geomagnetic field with the synodic cycle, with the modulation of this by the lunar-node cycle. The notion of an influence of the synodic cycle being modulated by the 18-year nutation cycle is supported by the present enquiry. One could choose to view this as, effectively, a 9-year cycle, insofar as no distinction was here made between the two lunar nodes. The method employed five successive lunar-days (one-sixth of the lunar month) to investigate the peaks and troughs of the synodic cycle.     

Lunar phobia in bats and its ecological correlates: A meta-analysis

Animals show several behavioral strategies to reduce predation risks. Presumably, moonlight avoidance is a strategy used by some nocturnal species to reduce the risk of predation. In bats, some research indicates that foraging activity is negatively correlated with moonlight intensity, a phenomenon better known as lunar phobia. However, the currently available evidence is contradictory because some bat species reduce their activity during nights with more moonlight while the opposite occurs in other species. We quantitatively evaluated the strength and direction of the relationship between moonlight intensity and bat activity using a meta-analysis. We also looked at some ecological correlates of lunar phobia in bats. Specifically, we examined foraging habitat and latitude as potential moderators of the size of the lunar phobia effect. Our results show that, regardless of the method used to evaluate bat activity, the overall relationship between moonlight intensity and bat activity is significant and negative (r = ?0.22). Species foraging on the surface of the water (piscivores and insectivores; r = ?0.83) and forest canopy species (i.e., big frugivores; r = ?0.30) are more affected by moonlight than those with different foraging habitats (understory, subcanopy, open air). Latitude was positively correlated with lunar phobia (r = 0.023). The stronger lunar phobia for bats foraging on the water surface and in the forest canopy may suggest that the risk of predation is greater where moonlight penetrates more easily. The significant effect of latitude as a moderator of lunar phobia suggests that there is a weak geographic pattern, with this phobia slightly more common in tropical bats than in temperate species.     

Effects of light dynamics on coral spawning synchrony

Synchrony of spawning in many hermatypic corals, typically a few nights after the full moon, is putatively dependent on solar and lunar light cycles in conjunction with other possible cues such as tides and temperature. We analyze here the contributions of separate components of light dynamics, because the effects of twilight and lunar skylight on coral spawning synchrony have previously been conflated and the alternative hypothesis that these components have differential contributions as proximate cues has not been tested. Moonlight-dependent changes in spectra during twilight, rates of decreasing twilight intensities, and changes in lunar photoperiod were experimentally decoupled using programmed light-emitting diodes and compared for their separate effects on spawning synchrony in Acropora humilis. Effects on synchrony under the control of synthetic lunar cues were greatest in response to changes in lunar photoperiod; changes in light intensities and spectra had lesser influence. No significant differences among treatment responses were found at the circa-diel time scale. We conclude that spawning synchrony on a particular lunar night and specific time of night is a threshold response to differential periods of darkness after twilight that is primarily influenced by lunar photoperiod and secondarily by discrete optical components of early nocturnal illumination.     

Lunar periodicity and the timing of river entry in Atlantic salmon Salmo salar

Historical catch records of Atlantic salmon Salmo salar from three rivers discharging to the Baltic Sea in an area free from tides and from strong effects of the moon on illumination were analysed to investigate whether timing of S. salar river entry was associated with lunar cycles directly. Although a significant effect of lunar phase on river entry was detected, with more fish entering rivers around the full moon than other phases, the effect of the lunar cycle was very small compared with other sources of variation. Hence, the biological role of lunar cycle as a determinant of the timing of S. salar runs in the investigated populations was negligible, suggesting that lunar cycle per se does not play a role in the timing of S. salar river entry.     

The search for indigenous lunar organic matter

Early lunar conditions are not inconsistent with the production of large quantities of prebiological organic matter now sequestered in the lunar subsurface. The absence of substantial water and organic compounds from the superficial layers of the lunar surface may not be indicative of the composition of deeper regions.     

Lunar-related reproductive behaviour in the badger (Meles meles)

Cyclicity in behaviours, including reproduction, in relation to the lunar cycle is widely documented in some phyla, but weak or unknown in Class Mammalia. In this paper we present long-term video surveillance data of wild Eurasian badgers Meles meles, which reveal a strong correlation between reproductive behaviour and the lunar cycle. Squat marking and raised-leg urination, which increase in frequency at times of reproductive activity, showed maxima around day 22 of the lunar cycle (i.e. new moon). These findings were supported by observations of matings, together with published records, which showed significantly higher occurrence in the lunar dark phase (last quarter to first quarter). We propose that the lunar cycle has the potential to act as a regulator of the reproductive cycle in the badger.     

Genetic architecture of local adaptation in lunar and diurnal emergence times of the marine midge Clunio marinus (Chironomidae, Diptera)

Circadian rhythms pre-adapt the physiology of most organisms to predictable daily changes in the environment. Some marine organisms also show endogenous circalunar rhythms. The genetic basis of the circalunar clock and its interaction with the circadian clock is unknown. Both clocks can be studied in the marine midge Clunio marinus (Chironomidae, Diptera), as different populations have different local adaptations in their lunar and diurnal rhythms of adult emergence, which can be analyzed by crossing experiments. We investigated the genetic basis of population variation in clock properties by constructing the first genetic linkage map for this species, and performing quantitative trait locus (QTL) analysis on variation in both lunar and diurnal timing. The genome has a genetic length of 167-193 centimorgans based on a linkage map using 344 markers, and a physical size of 95-140 megabases estimated by flow cytometry. Mapping the sex determining locus shows that females are the heterogametic sex, unlike most other Chironomidae. We identified two QTL each for lunar emergence time and diurnal emergence time. The distribution of QTL confirms a previously hypothesized genetic basis to a correlation of lunar and diurnal emergence times in natural populations. Mapping of clock genes and light receptors identified ciliary opsin 2 (cOps2) as a candidate to be involved in both lunar and diurnal timing; cryptochrome 1 (cry1) as a candidate gene for lunar timing; and two timeless (tim2, tim3) genes as candidate genes for diurnal timing. This QTL analysis of lunar rhythmicity, the first in any species, provides a unique entree into the molecular analysis of the lunar clock.     

The lunar cycle determines availability of coral‐reef fishes at fish markets

During 139 visits between March 2009 and May 2011, it was found that the availability of reef fishes at a local fish market in the Philippines was highly affected by the lunar cycle. The number of vendors selling reef fishes was significantly lower (13·4%) during third lunar quarters (full moon periods) than during the first, second and fourth lunar quarters (40·2, 25·0 and 30·0%, respectively). It is recommended that the influence of the lunar cycle on fish availability is considered when designing sampling strategies for catch surveys.     

Lunar phase-dependent expression of cryptochrome and a photoperiodic mechanism for lunar phase-recognition in a reef fish, goldlined spinefoot

Lunar cycle-associated physiology has been found in a wide variety of organisms. Recent study has revealed that mRNA levels of Cryptochrome (Cry), one of the circadian clock genes, were significantly higher on a full moon night than on a new moon night in coral, implying the involvement of a photoreception system in the lunar-synchronized spawning. To better establish the generalities surrounding such a mechanism and explore the underlying molecular mechanism, we focused on the relationship between lunar phase, Cry gene expression, and the spawning behavior in a lunar-synchronized spawner, the goldlined spinefoot (Siganus guttatus), and we identified two kinds of Cry genes in this animal. Their mRNA levels showed lunar cycle-dependent expression in the medial part of the brain (mesencephalon and diencephalon) peaking at the first quarter moon. Since this lunar phase coincided with the reproductive phase of the goldlined spinefoot, Cry gene expression was considered a state variable in the lunar phase recognition system. Based on the expression profiles of SgCrys together with the moonlight's pattern of timing and duration during its nightly lunar cycle, we have further speculated on a model of lunar phase recognition for reproductive control in the goldlined spinefoot, which integrates both moonlight and circadian signals in a manner similar to photoperiodic response.     

Lunar synchronization of testicular development and steroidogenesis in rabbitfish

Lunar synchronization of testicular development in the golden rabbitfish, Siganus guttatus, was assessed by measuring changes in sperm motility and conditions in the seminal plasma, and by in vitro production of steroid hormones in testicular fragments and sperm preparations. The duration and percentage of sperm motility was low 1 week before spawning (the new moon), but increased significantly on the day of spawning (the first lunar quarter). During the first lunar quarter, the osmolality decreased, but Ca(2+) concentration increased in the seminal plasma. These results suggest that spermiation occurs rapidly towards the specific lunar phase. Testicular fragments and sperm preparations were incubated with human chorionic gonadotropin (hCG) and two precursor steroid hormones, 17alpha-hydroxyprogesterone (17alpha-OHP) and testosterone (T), during the two lunar phases. The production of 11-ketotestosterone (11-KT) increased significantly when the testicular fragments were incubated with hCG at the first lunar quarter, while incubation of sperm preparations with 17alpha-OHP during the same moon phase resulted in a significant increase in 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP) production in the medium. These results suggest that 11-KT is produced in the somatic cells of the testis under the influence of gonadotropin, and that sperm can convert 17alpha-OHP to DHP. Additionally, steroidogenic activity was considered to increase toward the specific lunar phase. The synchronous increase in testicular activity supports the hypothesis that lunar periodicity is a major factor for the testicular development of S. guttatus.