Thursday, 24 July 2025

Pluto approaches opposition.

The Dwarf Planet Pluto will reach opposition (be directly on the opposite side of the Earth as the Sun) at 6.24 am GMT on Friday 25 July 2025. This means that it will be at its closest to the Earth this year, about 34.3AU (34.3 times the average distance between the Earth and the Sun, or about 3 639 716 200 km), and completely illuminated by the Sun. While it is not obvious to the naked eye observer, the planets have phases just like those of the Moon; being further from the Sun than the Earth, Pluto is 'full' when directly opposite the Sun, although with an apparent magnitude of only 15.0 it will take a reasonably good telescope to see Pluto at all, and it will only be visible as a star-like point to those that can see it. 

The relative positions of Earth and Pluto at 6.00 am on 25 July 2025. JPL Small Body Database.

Pluto was discovered in 1930 by Clyde Tombaugh, a young astronomer working at the Lowell Observatory in Arizona; its existence had been predicted as early as 1909, due to anomalies in the orbit of Neptune. At the time it was assumed that Pluto was a planet of some size, capable of disturbing the orbit of Neptune. Pluto spends part of its 248 earth year orbit inside the orbit of Neptune; this is not the same on every orbit, but alternates between a 20 and a 14 year stay.

The Dwarf Planet Pluto imaged by the New Horizons space probe in July 2015. NASA/JPL/Southwest Research Institute.

Pluto was downgraded from a planet to a dwarf planet by the International Astronomical Union in 2006, following the discovery of several similar small bodies in the Kuiper Belt beyond the orbit of Neptune. The term 'Dwarf Planet' is now used to designate objects large enough to form a roughly spherical shape under their own gravity, but no so massive as to have cleared the area around their orbit of all other objects. Pluto, Haumea, Makemake, and Eris were placed in this category, as was Ceres in the asteroid belt. Ceres had also been classified as a planet at the time of its discovery in 1801, as were a number of other asteroids until the mid-nineteenth century, when it became clear that asteroids were too abundant to be classed as planets.

The comparative sizes of Pluto, its largest moon, Charon, and the continental United States of America. Calvin Hamilton/Cornell University.

Pluto has an 247.7 year orbital period and an eccentric orbit tilted at an angle of 17.1° to the plane of the Solar System, which takes it from 29.6 AU from the Sun (i.e. 2960% of the average distance at which the Earth orbits the Sun) to 49.4 AU from the Sun (i.e. 4940% of the average distance at which the Earth orbits the Sun). As a body which spends most of its time outside the orbit of the planet Neptune it is classed as a Trans-Neptunian Object, even though it does come inside the orbit of Neptune for part of its orbital period.

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Rypticus africanus: A new species of Soapfish from the eastern Atlantic.

Soapfish, Grammistes and Rypticus spp., are bottom-dwelling Perciform Fish related to Groupers, generally found on reefs and other rocky marine environments. They get their common name from their ability to secrete a toxic, soapy, mucus as a defence mechanism. The genus Grammistes is restricted to the Indo-Pacific region, while members of the genus Rypticus are found in the Western Pacific, Atlantic and Caribbean. Only two species of Rypticus have been found on the African coast, the Greater Soapfish, Rypticus saponaceus, and the Spotted Soapfish, Rypticus subbifrenatus. The Greater Soapfish is known from both sides of the Atlantic being found from the coast of Florida, throughout the Caribbean, and as far south as Brazil in the western Atlantic, and from Mauritania south as far as Angola in the eastern Atlantic. However, a genetic study of museum specimens published in 2003 suggested that the eastern and western populations of the Greater Soapfish might in fact be separate species.

In a paper published in the Journal of Fish Biology on 21 July 2025, Gabriel Soares Araujo of the Center for Marine Biology at the University of São Paulo, Cláudio Sampaio of the Laboratório de Ictiologia e Conservação at the Universidade Federal de AlagoasLuiz Rocha of the  Department of Ichthyology at the California Academy of Sciences, and Carlos Eduardo Ferreira Leite of the Departamento de Biologia Marinha at the Universidade Federal Fluminense, re-examine the genetics of the Greater Soapfish, and formally describe the populations from the African coast as a separate species.

Araujo et al. examined specimens from Cape Verde, Ghana, São Tomé and Príncipe, and Togo. All were found to be genetically distinct from western Atlantic specimens of Rypticus saponaceus, forming a distinct population which is estimated to have split from the west Atlantic population in the Early Pleistocene, about 2.5 million years ago, at the onset of the Pleistocene, and surprisingly being more closely related to the Pacific Rypticus bicolor. Since Rypticus saponaceus was originally described from specimens from Florida, the east Atlantic population is described as a new species, which Araujo et al. name Rypticus africanus.

Time-calibrated phylogeny of the genus Rypticus based on mitochondrial COI gene sequences. Values near the nodes represent estimated divergence times (Mya). The 95% highest posterior density intervals are shown in parentheses. Coloured circles represent the biogeographic regions where species of Rypticus are distributed. Vertical bars depict the results of lineage delimitation tests. Araujo et al. (2025).

Specimens of Rypticus africanus examined range from 112 to 215 mm in length, and have three dorsal fin spines, 22-24 dorsal fin rays, 15-17 anal fin rays, 16-18 pectoral fin rays, and 24-25 caudal (tail) fin rays. The head is distinctly pointed, the dorsal fin originates slightly posterior to upper end the of gill opening, and the tail is rounded. They are brown or dark grey in colour, with numerous pale round spots of variable size on their flanks.

(a)–(c) Rypticus africanus from São Tomé and Príncipe, illustrating the variation in colour pattern between individuals: (a) São Tomé Island, (b), (c) Príncipe Island and (d) Rypticus saponaceus from Salvador, Bahia, Brazil, shown for comparison. Araujo et al. (2025).

Although Rypticus africanus has only been sampled from four areas (Cape Verde, Ghana, São Tomé and Príncipe, and Togo), Araujo et al. believe the name should be applied to all African populations currently described as Rypticus saponaceus, from Mauritania to Angola.

See also

Saturday, 12 July 2025

Clay figurines from the Middle to Late Preclassic San Isidro Site of western El Salvador.

Bolinas-type figurines are clay figurines from the Middle Preclassic (1000-350 BC) and Late Preclassic (350 BC-250 AD) periods of Mesoamerica, known from a number of sites along the Pacific coasts of Guatemala and El Salvador. They get their name from the Finca Bolinas Ranch in El Salvador, where the first examples were discovered in the mid-twentieth century. A total of 95 figurines were unearthed at Finca Bolinas, although not by an organised archaeological excavation, so much of the context in which they were originally buried has been lost. 

Of these 95 figurines, 93 were female and only two were potentially male. They were depicted either standing or sitting with their legs parted. The largest figurines were over 20 cm tall. The figurines were made from a cream or reddish-brown material, were evenly fired, and then smoothed or polished. Most of the figurines from Finca Bolinas have traces of either white or orange slips (some have both), and a few have traces of black paint. Most wear some kind of jewellery, such as anklets, bracelets, necklaces, or earspools, and most have hair styles, including simple buns, curls, braids, and more elaborate coiffures. Some of the figurines which lack earspools have holes in their earlobes, which have been interpreted as possible attachments for earspools made from a different material, such as jade. Many of the figurines are naked, others have coverings on their lower bodies, leaving their chests exposed, although breasts are either very small or absent completely. Most figurines are cast  in a single piece, but some have protrusions and sockets which enable articulated heads or limbs to be attached.

Bolinas-type figurines were also found at the monumental Kaminaljuyu site in Guatemala City, which was excavated in the 1940s and 1950s by the Carnegie Institution, and later excavations at Vista Hermosa in Guatemala, and Santa Leticia, and Ataco  Zapotitán Valley in El Salvador, though all of these figurines were fragmentary in nature, leading the archaeologists studying them to conclude that these were mundane domestic objects, possibly toys for children, which were deposited on household middens at the end of their usefulness, and then sometimes recycled into core-fill for monumental structures. 

In 2012 an excavation at Tak’alik Ab’aj on the Pacific-facing piedmont of the western Guatemalan highlands uncovered a burial with lavish funerary offerings comprised several high-quality ceramic vessels, jade jewellery, including a four-string necklace with a celtiform pendant in the form of an avian personage, and, in one corner, six broken but complete Bolinas figurines. This burial was dated to the Nil 2 ceramic phase of the late Middle Preclassic Period, or between 350 and 100 BC. 

The Bolinas figurines from Tak’alik Ab’aj were placed overlapping one-another, arranged along a north-south axis. All were standing naked females, placed with their arms band and their hands on their stomachs, their eyes open, and their lips parted to reveal their teeth. The smallest figurine was 273 mm tall, the largest 424 mm. One had an articulated head, which could be turned to face to the sides, two had apparently been painted with elaborate black markings. All were capable of standing, despite having distinctively small feet.

Figurines from Tak’alik Ab’aj with elaborate black markings on their backs. Schieber de Lavarreda (2016).

In a paper published in the journal Antiquity on 5 March 2025, Jan Szymański and Gabriela Prejs of the Faculty of Archaeology at the University of Warsaw, describe a set of five Bolinas figurines from the top of a large monumental structure at San Isidro, a large Middle to Late Preclassic site in the Department of Sonsonate, western El Salvador, during field work in 2022.

The layer from which the figurines was recovered has been dated by ceramic typology and radiocarbon assays to between 410 and 380 BC, slightly older than the Tak’alik Ab’aj site. The five figurines were found at the southern end of the excavated area. Three of the figurines are approximately 30 cm high, and made of a fine, cream-coloured material, while the remaining two are smaller, at 18 and 10 cm, and made of a courser, orange-brown paste. All had apparently been covered by a white slip, which can be seen best on the legs and lips, patches of red slip can be seen on the backs of the figurines. The three large figurines have articulated heads, with a protruding neck which fits into a socket on the base of the head. Each of the heads has a pair of holes drilled into the top, while the necks have a horizontal hole and a vertical groove on each side, which would have allowed a string to be passed through, holding the head in place; this is identical to the means of articulation seen at Tak’alik Ab’aj.

Five figurines from the San Isidro deposit. Scale is in centimetres. Julia Przedwojewska-Szymańska in Szymański & Prejs (2025).

The three larger figurines lack any hair or jewellery, while the two smaller figurines have locks on their foreheads and earspools; the smallest figurine also has bracelets and what appears to be a necklace on the chest.  This smallest figurine has its hands beneath its chin, while those of all the others lie on their abdomens. Both small figurines and two of the females are interpreted as female, while one of the larger figurines is interpreted as male, on the basis of its more elongated torso and shorter, thinner hips, and an incised linear pattern on the face, which appears to represent tattoos or scarification. If identified ccorrectly, this is the most complete male Bolinas figurine discovered to date.

Protrusion and socket allowing for articulation of the head seen in all three large figurines. Julia Przedwojewska-Szymańska in Szymański & Prejs (2025).

All of the figurines were discovered within an area of 0.6 m², at a depth of less than 50 cm below the surface. The figurines were all orientated 15° north of east-west, except the smallst, which was orientated 15°east of north-south. The larger figurines are also orientated with their feet along a line 15°east of north-south, parallel to the axis of the smallest figurine. The northernmost figurine is one of the large females, face down, with her head to the west. South of this, the second large female figurine lies face up with her head to the east. Next the smallest figurine lies face down with her head to the north (and the second female figurine), then the larger of the two small figurines, face up and head to the east, parallel to the two large figurines in this orientation, but without her feet on the same line. Finally, the large male figurine lies on his back with his feet to the west and head to the east, parallel to the other figurines in this position, with his feet on the line as the two large female figurines.

Head of the male figurine with tattoos or scarification. Width 55mm. Julia Przedwojewska-Szymańska in Szymański & Prejs (2025).

The figurines appear to have been deliberately placed in a planned out way, however, Szymański and Prejs note that the site was excavated on freely-accessible agricultural land (i.e. not a secure site) over a period of several days. Furthermore, the spot where the figurines were found was covered by a Bullhorn Tree, Acacia cornigera, with roots passing through the figurine-containing area, which may have moved their position over time.

Reconstructed topography of the tableau as it appeared in situJulia Przedwojewska-Szymańska in Szymański & Prejs (2025).

The larger dolls, with their movable heads, invite comparison to modern dolls. However, clay is a poor material choice for toys, and the long limbs of the figurines would seem likely to break quickly in any form of play, leading Szymański and Prejs to conclude that the purpose of the figurines is more likely to have been artistic or ritual. They build upon this to suggest that the movable heads imply that they may have been used as marionettes or puppets, either to act out some ritual performance, or arranged in some form of tableaux.

The Bolinas-type figurines from Tak’alik Ab’aj were also apparently arranged in a form of tableaux, with figurines placed in pairs on the cardinal directions along a scaled-down horizon circle. This led archaeologist Christa Schieber de Lavarreda to propose that the figurines were used in an elaborate ritual at the end of funerary rights, in the form of a dance representing the movements of the Sun and the cycle of life.

Choreography of the ancestral conception of the world governed by the cardinals and the sacred circle of life emerging from death, personified in the cycle of corn and the sun represented by the figurines of the 'Las Manecas' Offering from Burial No. 2 of Tak’alik Ab’aj (inserted in the landscape to the southwest at dusk, seen from Mound 5 of Tal’alik Ab’aj). Tak’alik Ab’aj National Archaeological Park. Schieber de Lavarreda (2016).

The figurines from San Isidro resemble those from Tak’alik Ab’aj in that they will stand upright unaided, which raises the possibility that these figurines were also used to act out some sort of scene before burial. The figurines are broken in a number of places which do nor appear to be obvious week points, which may indicate that they were deliberately broken before being buried, although Szymański and Prejs observe that they are likely to have been made in more than one piece and then assembled, which would have created week points in less obvious places.

The arrangement of the figurines at San Isidro is clearly non-random, and therefore presumably had some significance to the people who deposited them. Notably, all of the figurines, if returned to an upright position would have faced to the west, except for the smallest, which may have faced north, or may have been disturbed by the growth of the tree roots. The west, in Mesoamerican cosmography, is generally considered to be the realm of death (although this understanding is largely derived from Mayan culture). This may indicate that the placement of the San Isidro figurines was part of a funerary right, despite the absence of any Human remains at the site. 

San Isidro is a complex of structures; figurines were recovered from the top of a mound designated Cerrito 1, which lies on the eastern side of a plaza. On the western side of this plaza lies a smaller structure, designated Trapiche 3, from which a large, unmarked, stela (slab) was recovered in 2018. Facing in a 15°-north-of-west direction, the San Isidro figurines would have looked directly at the Trapiche 3 mound and its stela.

Plan view of the centre of San Isidro based on photogrammetry. Joachim Martecki in Szymański & Prejs (2025).

The three large figurines from San Isidro are naked, which is not unusual in Bolinas figurines, lack any jewellery, although the large holes in the ears may have served as attachments for earspools, and all lack hair, which is more unusual. It is possible that all these features were made of perishable material and have perished since their burial.

Plain stela found atop the Trapiche 3 structure at San Isidro in 2018. Raul Cea in Szymański & Prejs (2025).

All the San Isidro figurines have their mouths open, which may imply that they were intended to be depicting people engaged in speech or song. The smallest figurine also has its hands raised to its chin, which is harder to interpret. Hands covering the mouth might indicate the keeping of secrets, but this is not the case. Possibly the figurine was originally intended to be holding a whistle or ocarina, or possibly just a food item. White kaolin has been found in the mouths of all five figurines, which might relate to some form of feeding ritual.

The heads of the larger figurines appear to have been adjustable rather than truly movable, and it is unclear how this would have been used. Possibly the heads were placed in different positions at different points in the ritual. Alternatively, the figurines may have had a longer life cycle, being used in multiple rituals before their eventual burial, leading to a need for adjustable, or even replaceable, heads for different rituals.

The San Isidro figurines are only the second Bolinas figurines discovered in situ, which limits the amount which should be inferred from them. What can be stated with some confidence is that their placement is non-random, although the purpose of the way in which they are arranged is far from certain. The presence of figurines in a prone (face down) position is curious. If these figurines were intentionally placed in this position, then was there some significance to it. Burial of Humans in a prone position is also known from Mesoamerica, including Preclassical El Salvador, although this is rare, and the reason behind it is unknown.

It is also unclear whether the figurines represent actual people. It is possible that the male figurine represents a ruler or other important figure, and that the two large female figurines represent wives (one of whom might have pre-deceased him, indicated by having her figurine placed face down) and the two smaller figurines daughters, again, with one placed face down, potentially representing having predeceased her father. Alternatively, the figurines might represent household deities similar to the Roman lares and penates, or possibly anthromorphised depictions of cultural concepts, such as the statues of justice seen on court houses in many parts of the world today. Another possibility is that they are intended to be ritual servants for the afterlife, similar to the ushabti figurines placed in tombs by the Ancient Egyptians. Szymański and Prejs suggest that the markings on the face of the male figurine may indicate that he represents an actual person, while they are less certain about the more generic female figurines.

As well as the figurines, there are other items which were found at both Tak’alik Ab’aj and San Isidro, such as miniature jade celtiform pendants representing avian personages, and tubular and disk beads made using similar techniques. Nevertheless, the Tak’alik Ab’aj site was clearly a burial, while no evidence of Human remains, or even a place where they might once have been placed, has been found at San Isidro. At both sites, the figurines were clearly laid out in a specific arrangement, but the arrangements were different, possibly providing further evidence that the purpose of the two sites was different.

Szymański and Prejs believe that ritualised puppet-theatre was practiced in late Middle Preclassic and early Late Preclassic periods in south-eastern Mesoamerica. They suggest that at least some of the figurines were interchangeable in purpose, generic enough that different costumes and heai pieces would have allowed them to undertake different roles in different performances, while other figurines may have been more specific in their purpose.

See also...

Saturday, 5 July 2025

3I/Atlas: Third interstellar comet discovered.

On Tuesday 1 July 2025 scientists at the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Río Hurtado, Chile, observed a body 4.53 AU from the Sun (i.e. 4.53 times as far from the Sun as the planet Earth) between the constellations of Serpens Cauda and Sagittarius, which was given the provisional designation A11pl3Z. This object was travelling towards the Inner Solar System at a speed of 65 km per second, on what appeared to be a more-or-less straight trajectory, highly unusual in a body orbiting the Sun.

Discovery images for object A11pl3Z. ATLAS/University of Hawaii/NASA/Wikipedia.

A series of follow-up observations  by both professional and amateur astronomers confirmed that the body was a comet on a hyperbolic trajectory (a trajectory which will take it straight through the Solar System and out into interstellar space. Most such parabolic comets derive from the Oort Cloud, a vast disc of thinly spread cometary bodies between 2000 and 200 000 from the Sun. These comets are knocked from their orbits be close encounters with other bodies, plunge through the Inner Solar System once, then vanish into the depths of space. However, two previous comets have been found to be on trajectories which cannot be explained in this way, these being 1I/‘Oumuamua and 2I/Borisov, and on Tuesday 2 July it was confirmed that A11pl3Z was a third such body, leading to it being given the designation 3I/Atlas, in which the 'I' stands for 'Interstellar body', the '3' indicates that it was the third such body discovered, and 'ATLAS' refers to the ATLAS asteroid impact early warning system, which discovered the object.

The trajectory and current position (on 5 July 2025) of interstellar comet 3I/ATLAS. The Sky Live.

3I/ATLAS is predicted to reach its perihelion (closest point on its trajectory to the Sun) on 29 October 2025, when it will be 1.36 AU from the Sun. It will make its closet approach to the Earth on 19 December, when it will be 1.80 AU from us. Unfortunately, these events will happen while the comet is on the far side of the Sun, preventing observations during this period. The comet will pass the planet Mars at a distance of 0.19 AU on 3 October, and Jupiter at 0.38 AU on 16 March 2026. 3I/ATLAS is apparently a weekly active comet with an absolute magnitude of about 12 (a measure of its brightness), which implies a nucleus with a diameter of 3-5 km.

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Friday, 4 July 2025

Necrosyrtes monachus: Mass death of Hooded Vultures reported in The Gambia.

A mass death event affecting Hooded Vultures, Necrosyrtes monachus, has occurred in the town of Gunjur, in Kombo South District, The Gambia, according to the West African Bird Study Association. The association was contacted by local residents at 11.00  am local time on Thursday 3 July 2025, by local residents concerned by the sight of a large number of dead and dying Birds. When a team of researchers led by Fagimba Camara arrived at the site, they found 23 dead Vultures and a 24th in a sick and distressed condition.

A researcher from the West African Bird Study Association collecting dead Hooded Vultures, Necrosyrtes monachus, in Gunjur, The Gambia, following a mass death event on Thursday 3 July 2025. West African Bird Study Association.

Hooded Vultures are classed as Critically Endangered under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species. There are thought to be around 131 000 adult Hooded Vultures alive, spread across 45 African countries. However, the species is estimated to have suffered a 68% population decline in three generations, and sudden population collapses have been recorded in several countries, including Côte d’Ivoire, Togo, Benin, Ghana, Nigeria, Kenya, and Botswana, and illegal killings of Birds have been recorded in several countries, including Guinea Bissau, Burkina Faso, and The Gambia.

The current distribution and conservation status of the Hooded Vulture, Necrosyrtes monachusInternational Union for the Conservation of Nature.

The researchers from the West African Bird Study Association have collected samples from the Gunjur Vultures for analysis, but it is thought most likely that the Birds have died as a result of poisoning. This is the most common cause of mass deaths among Vultures, not because they are targeted themselves, but because they will eat both bait put out for large predators which target livestock (itself an illegal activity in almost all countries), as well as the bodies of other Animals which have been poisoned, intentionally or otherwise.

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