Neptune approaches opposition.

The planet Neptune will reach opposition (i.e. be directly opposite the Sun seen from Earth) on 0.08 am GMT on Saturday 21 September 2024. This means that it will both be at its closest to the Earth this year, about 28.93 AU (28.96 times the average distance between the Earth and the Sun, or about 4 328 336 000 km), and completely illuminated by the Sun. While it is not visible to the naked eye observer, the planets have phases just like those of the Moon; being further from the Sun than the Earth, Neptune is 'full' when directly opposite the Sun. As this falls shortly after the Full Moon on 18 September in the constellation of Auriga, the prospects for viewing somewhat limted this year. The planet will be in the constellation of Pisces and at its highest point in the sky at about midnight local time from anywhere on Earth. 

The relative positions of the Earth and the planets of the Outer Solar System on 21 September 2024.  JPL Small Body Database. 

Neptune orbits the Sun at an average distance of 30.11 AU, completing one orbit around the Sun every 165 years. This means that the planet is almost stationary compared to the faster moving Earth, so that it reaches Opposition only four days later each year than the year before, and reaches Solar Conjunction (when it is directly on the opposite side of the Sun to the Earth), roughly six months later.

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Magnitude 5.2 Earthquake in Buzău County, Romania.

The Centre Sismologique Euro-Méditerranéen recorded a Magnitude 5.2 Earthquake at a depth of 131 km, roughly 16 km to the north of the town of Nehoiu in Buzău County, in southeast the Muntenia region of Romania, at about 6.40 pm local time (about 2.40 pm GMT) on Monday 16 September 2024. There are no reports of any damage or injuries arising from this event, but it was felt over much of eastern Romania, Moldova, and western Ukraine. This pattern of causing little damage but being felt a considerable distance from the epicentre is typical of deep Earthquakes, the energy of which is dispersed over a wide distance before reaching the surface.

The approximate location of the 16 September 2024Buzău County, Earthquake. USGS.

The Carpathian Mountains of Romania form part of the suture formed when the Tethys Ocean closed during the Mesozoic, joining the continents of Laurasia (to the north) and Gondwana (to the south). The area is now internal to the Eurasian continent, but the area to the south, known as the Moesian Platform, has a separate origin to the rest of Europe. This system is once again being stressed by the impact of Africa into Eurasia from the south, with the Anatolian Plate (which underlies Anatolian Turkey), Aegean Plate (which underlies southern Greece) and Adriatic Plate (which underlies eastern Italy and the western Balkan Peninsula) caught between the two larger units, leading to a more complex interplay of stresses across southeastern Europe. The Anatolian and Aegean Plates are located to the south of the Moesian Platform, and are being pushed to the west, while the Adriatic Plate lies to the west of the Aegean Plate and Moesian Platform, and is being pushed to the northeast.

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Partial Lunar Eclipse on 18 September 2024.

A partial Lunar Eclipse will occur on Wednesday 18 September 2024, starting at 0.41 am GMT. The whole eclipse will be visible across all of South America and the Atlantic, and most of North America, Europe, Africa, and parts of the Middle East, while part of the eclipse will be visible from the northwest of North America, the Horn of Africa, European Russia, the remainder of the Middle East, and parts of western Asia and the Indian Ocean. although in these areas the Moon will either rise part way through the eclipse, or set before it is complete.

Areas from which the 28 October 2023 Lunar Eclipse will be visible. Dominic Ford/In the Sky.

The Moon produces no light of its own, but 'shines' with reflected light from the Sun. Thus, at Full Moon the Moon is on the opposite side of the Earth to the Sun, and its illuminated side is turned towards us, but at New Moon the Moon is between the Earth and the Sun, so that its illuminated side is turned away from us.

Lunar eclipses occur when the Moon passes through the Earth's shadow. This can only happen at Full Moon (unlike Solar Eclipses, which happen only when the Moon passes between the Earth and the Sum, and therefore only occur at New Moon), but does not happen every Lunar Month as the Sun, Moon and Earth are not in a perfect, unwavering line, but rather both the Earth and the Moon wobble slightly as they orbit their parent bodies, rising above and sinking bellow the plane of the ecliptic (the plane upon which they would all be in line every month).

Because the Moon is passing through a shadow, rather than being blocked from our view, it does not completely disappear during an eclipse like the Sun, but in a total Lunar Eclipse goes through two distinct phases of dimming, the Penumbra, when it is still partially illuminated by the Sun, and the Umbra, when the Earth completely blocks direct sunlight from the Moon. This does not result in complete darkness, as the Moon is still partially lit by reflected Earthlight, but it does turn a deep, dark red colour.  In a partial eclipse the Earth passes completely through the Moon's penumbra, but only partly through its umbra.  

Phases of the 18 September 2024. NASA Eclipse Website.

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Jiucaiyuangnathus confusus: A new species of Baurioid Therocephalian from the Eartly Triassic of Xinjiang Province, China.

The Bogda Mountains of northeastern Xinjiang Province, China, preserve a Permian-Triassic sequence which has produced a broad range of terrestrial Vertebrates, including non-Mammalian Therapsids such as Dicynodonts, Gorgonopsians, and Therocephalians. Two Therocephalians have been described from this sequence to date, Urumchia lii from the Early Triassic Jiucaiyuan Formation, and Dalongkoua fuae from the Late Permian Guodikeng Formation, although several other species are known from elsewhere in North China, including Shiguignathus wangi, Jiufengia jiai, Euchambersia liuyudongi, and Caodeyao liuyufengi from the Late Permian Naobaogou Formation of Inner Mongolia, Moschowhaitsia lidaqingi from the Late Permian Wufoshi Formation of Gansu Province, Hazhenia concava from the Early Triassic Heshanggou Formation of Inner Mongolia, Ordosiodon lincheyuensis, Ordosiodon youngi and Nothogomphodon sanjiaoensis from the Early Triassic Ermaying Formation of Shanxi Province, Yikezhaogia megafenestrala. from the Early Triassic Ermaying Formation of Inner Mongolia, and Traversodontoides wangwuensis from the Middle Tirassic Ermaying Formation of Henan Province.

In a paper published in the journal Vertebrata PalAsiatica on 20 July 2024, Lui Jun of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences and the College of Earth and Planetary Sciences of the University of the Chinese Academy of Sciences, and Fernando Abdala of the Área de Paleontología at Unidad Ejecutora Lillo and the Evolutionary Studies Institute at the University of the Witwatersrand, describe a new species of Baurioid Therocephalian from the Early Triassic Jiucaiyuan Formation of Jimsar County in Xinjiang Province, China.

The new species is described from a slab on which a partial snout and several postcranial skeletal elements were visible on the surface. When X-ray microcomputed tomography was applied to this slab it was discovered that two largely disarticulated partial skeletons were present within. The partial skeleton is designated as the holotype of the new species (in taxonomy, a specimen is named as the holotype when an new species is discovered, and any other specimens are deemed to belong to that specie species if the can be shown to belong to the same species as the holotype), which is given the name Jiucaiyuangnathus confusus, where 'Jiucaiyuangnathus' means 'Jiucaiyuan-jaw', in reference to the Jiucaiyuan Formation, and 'confusus' means 'confusing' in reference to the difficulty had deciphering the specimens. It is thought that the snout is derived from one of the post-cranial skeletons, but it is impossible to tell which.

Jiucaiyuangnathus confusus (IVPP V32945, holotype) from Jimsar, Xinjiang. (A)–(C) photo (A) and 3D rendering (B) of the left side of the snout in lateral and 3D rendering of the medial view of the left side of the snout (C); (D). 3D rendering of the snout in posterior view showing the bones as preserved. Abbreviations: afo. anteriormost foramen; cc. christa choanalis; F. frontal; L. lacrimal; l.c. lacrimal canal; M. maxilla; m. maxillary tooth; m.a. maxillary antrum; msf. maxillo-septomaxillary foramen; pdl. dorsal layer of palatine; pit. maxillary round pit; PL. palatine; PM. premaxilla; pml. medial layer of palatine; sH, sinus Highmore; SM. septomaxilla; V. vomer. Lui & Abdala (2024).

The preserved portion of the jaws has five surviving incisors and lacks canines. There is a diastema (gap) between the last incisor in the upper jaw and the first maxillary tooth, but no equivalent gap is present in the dentition of the lower jaw, traits consistent with Jiucaiyuangnathus confusus being a Baurioid Therocephalian.

3D rendering of Jiucaiyuangnathus confusus (IVPP V32945, holotype) from Jimsar, Xinjiang . (A) The preserved snout in ventral view; (B), (C) vomer in dorsal (B) and ventral (C) views, vomer is reconstructed in the natural position in (C); (D) left dentary in lateral view; (E), (F) mandibles in dorsal (E) and ventral (F) views. Abbreviations: 1st ic. first incisor; ch. choana; D. dentary; d. dentary tooth; F. frontal; for vn. place for vomeronasal organ; M. maxilla; N. nasal; PL. palatine; PM. premaxilla; SP. splenial; V. vomer; v.f. vomerine foramen. Lui & Abdala (2024).

The two partial skeletons are given the designations IVPP V32946-1 (which is marginally the smaller of the two) and IVPP V32946-2 (which is marginally the larger). While both are largely disarticulated, most of the bones are close to their original positions, making it possible to assign them to one of the two skeletons wirh confidence. In both skeletons, the neural arches are separate from the centra of the vertebrae, making it likely that they were juveniles at the time of death.

Posterior skeletons of Jiucaiyuangnathus confusus (IVPP V32946) from Jimsar, Xinjiang  (A), (B) photo of the slab; (C), (D) 3D rendering of bones. Gray (IVPP V32946-1) and light purple (IVPP V32946-2) are bones of each specimen. Light blue uncertain. Lui & Abdala (2024).

Specimen IVPP V32946-1 has ten presacral vertebrae preserved, the the atlas and axis, five thoracics, and three lumbars, as well as three sacral vertebrae and a series of at least 11 caudal vertebrae, five of them being rod-like. There are three short, curved cervical vertebrae, and five incomplete ribs on the left side and seven nearly complete ribs on the right side of the thoracic vertebrae. An almost complete pelvic girdle lacks only the left ischium. A right femur, lacking a proximal end and with an incomplete distal end, probably belongs to this skeleton.

3D rendering of Jiucaiyuangnathus confusus  (IVPP V32946-1) from Jimsar, Xinjiang.  (A), (B) The preserved skeleton in dorsal (A) and ventral (B) views; (C) right femur in distal view; (D)–(F) atlas and axis in anterior (D), left (E), and right (F) lateral views; (G) four thoracic vertebrae in right lateral view; (H), (I) sacral region in lateral (H) and dorsal (I) views; (J) caudal vertebrae Abbreviations: aic. atlas intercentrum; cdr. caudal rib; cdv. caudal vertebra; cr. cervical rib; FE. femur; lv. lumbar vertebra; ns. neural spine; sr. sacral rib; sv. sacral vertebra; tp. transverse process; tr. thoracic rib; tv. thoracic vertebra. Lui & Abdala (2024).

Specimen IVPP V32946-2 has ten continuous vertebrae, interpreted as thoracics, as well as 13 complete long left thoracic ribs and the proximal side of eight right thoracic ribs. The head of the first sacral rib is considerably expanded dorsoventrally with a short, stout shaft curving ventrally and a very expanded distal end to contact the ilium. This specimen has a nearly complete left scapula and the dorsal portion of the right scapula, as well as a separated procoracoid, which lies close to the ventral side of the scapula. An incomplete interclavicle appears as a broad flat bone that gently curves ventrally, and the sternum is preserved as a large, thin, longer than wide flat plate. Again, the pelvic girdle is almost complete, in this case lacking the left pubis. The proximal parts of both femurs are preserved, with the right being more complete.

3D rendering of Jiucaiyuangnathus confusus (IVPP V32946-2) from Jimsar, Xinjiang. (A), (B) Skeleton in dorsal (A) and ventral (B) views; (C) part of thoracic vertebrae in left lateral view; (D) two sacral and three anterior caudal ribs; (E)–(H) sacral ribs of (D) in dorsal (E), (G) and ventral (F), (H) views; (I)–(L) two smaller sacral ribs in dorsal (I), (K) and ventral (J), (L) views Abbreviations: cdr. caudal rib; mt. metatarsal; sr. sacral rib. Liu & Abdala (2024).

Neither of the skeletons has neural arches fused to the centra, suggesting that they were both juveniles when they died, but the neural arches of the smaller skeleton are more distant from the centra than in the larger, possibly suggesting that it was younger and less developed. There are also differing degrees of ossification in the bones of the pelvic girdle of the two skeletons, which again suggest different levels of development. 

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Asteroid 2024 RL8 passes the Earth.

Asteroid 2024 RL8 passed by the Earth at a distance of about 329 350 km (1.12 times the average distance between the Earth and the Moon, or 0.29% of the distance between the Earth and the Sun), with a relative velocity of about 13.33 km per second, slightly before 10.40 pm GMT on Wednesday 11 September 2024. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2024 RL8 has an estimated equivalent diameter of 6-19 m (i.e. it is estimated that a spherical object with the same volume would be 6-19 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) between 40 and 22 km above the ground, with only fragmentary material reaching the Earth's surface.

300 second image of 2024 RL8 taken with the Elena Planetwave 17" Telescope at Ceccano in Italy on 9 September 2024. The asteroid is the small point at the centre of the image, indicated by the white arrow, the longer lines are stars, their elongation being caused by the telescope tracking the asteroid over the length of the exposure. At the time when the image was taken, the asteroid was about 2.5 million km from the Earth. Gianluca Masi/Virtual Telescope Project.

2024 RL8 was first detected on 7 September 2024 (four days before its closest approach to the Earth), by the University of Hawaii's PANSTARRS2 telescope. The designation 2025 RL8 implies that it was the 211th asteroid (asteroid L8 - in numbering asteroids the letters A-Z, excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that L8 = (25 x 8) + 11 = 211) discovered in the first half of September 2024 (period 2024 R; the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The relative positions of 2024 RL8 and the Earth on at 11.00 pm on Wednesday 11 September 2024. JPL Small Body Database.

2024 RL8 is calculated to have a 480 day (1.31 year) orbital period, with an elliptical orbit tilted at an angle of 12.01° to the plain of the Solar System which takes in to 0.71 AU from the Sun (71% of the average distance at which the Earth orbits the Sun, and slightly inside the orbit of Venus) and out to 1.69 AU (1.69 times the distance at which the Earth orbits the Sun, more than the distance at which the planet Mars orbits). 

The positions and orbits of 2024 RL8 and the planets of the Inner Solar System at 11.00 pm on Wednesday 11 September 2024. JPL Small Body Database.

2024 RL8 is therefore classed as an Apollo Group Asteroid, which is an asteroid that is on average further from the Sun than the Earth, but which does get closer. 2024 RL8 is calculated to have fairly regular close encounters with the Earth, with the last thought to have happened in September 2020 and the next predicted for August 2028. The asteroid is also predicted to have regular close encounters with the planet Venus, with the last thought to have happened in June 2019 and the next predicted for June 2027.

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