2017 OF201: A potential Dwaf Planet with an extremely wide orbit.

The majority of the known sub-planetary bodies of the Solar System are found within the Main Asteroid Belt, but the total mass of the bodies here is thought to add up to only about 0.04% of the mass of the Earth. The Kuiper Belt, located between 30 and 50 AU from the Sun (i.e. between 30 and 50 times as far from the Sun as the Earth) is thought to contain a total mass of about 2% that of the Earth, including large icy bodies such as the Dwarf Planet Pluto. Beyond this, at a distance of between about 2000 and 200 000 AU from the Sun, the Oort Cloud may contain several Earth masses of material, largely in the form of icy comets, but also including dwarf planets, and possibly unidentified planets.

Other than the Dwarf Planet Pluto, which was discovered in 1930, all of the 5000 plus known trans-Neptunian objects (Solar System bodies outside the orbit of the Planet Neptune) have been discovered in the past three decades. Most of these have been discovered by surveys concentrating on the elliptic plane of the Solar System, with higher latitudes very poorly mapped. The limitations of the instruments used also mean that few objects beyond 60 AU from the Sun have been discovered.

Cosmological surveys (i.e. surveys of the deeper cosmos, outside the Solar System) have also detected trans-Neptunian objects, most notably the Dark Energy Survey, which has already discovered about 800 such bodies.

In a paper published on the arXiv database at Cornell University on 22 May 2025, Sihao Cheng of the Institute for Advanced Study and the Perimeter Institute, and Jiaxuan Li and Eritas Yang of the Department of Astrophysical Sciences  at Princeton University, detail the discovery of  a large and exotic trans-Neptunian object from data collected by the Dark Energy Camera Legacy Survey.

Cheng et al. searched data collected by thee Dark Energy Camera Legacy Survy, which utilises the Dark Energy Camera on the 4-meter Blanco telescope at Cerro Tololoin Chile, discovering the same object had been detected at three wavelength bands on ten occasions between 2014 and 2018, and that it was possible to connect these sightings and calculate a tentative orbit for the object. This object, identified as 2017 OF201 (a name which implies it was the 5031st object discovered in the second half of July 2017) had an extremely wide and excentric orbit, was about 85 AU from the Sun was detected, and had an apparent magnitude of about 22.6, making it the second brightest object yet discovered with an orbital distance greater than 80 AU.

Armed with this data, Cheng et al. searched the data archives of the 3.6 m Canada-France-Hawaii Telescope, the Subaru Telescope, and Gemini-North Telescope, recovering images of 2017 OF201 at the predicted positions in  nine 3.6 m Canada-France-Hawaii Telescope images from 2011 and 2012, but not detecting it in data from the Subaru or Gemini-North telescopes.

Trajectory of 2017 OF201 on the sky from 2011 to 2018. Individual detections from 13 nights are shown on top of the predicted trajectory based on the best-fit orbit, which describes the detections very well with a scatter of 0.13 for the Dark Energy Camera (DECam) and 0.03 for the Canada-France-Hawaii Telescope (CFHT) arcsec in each component, consistent with the estimated astrometric error. The insets show example images from DECam (r-band on 2017-09-17) and CFHT (r-band on 2011-08-31). Cheng et al. (2025).

2017 OF201 is calculated to have an orbital period of 24 256 years, with a perihelion distance (closest approach to the Sun) of 44.9 AU, an aphelion distance (furthest distance from the Sun) of 1632 AU, and a semi-major axis (average distance from the Sun) of 838.3 AU. The last perihelion of 2017 OF201 was in 1930, the year in which Pluto was discovered, however, even at perihelion 2017 OF201 would have been about four orders of mangnitude fainter than Pluto (i.e. roughly a ten thousandth as bright), quite beyond detection by the telescopes of the day. The orbit of 2017 OF201 is tilted at 16.2° to the plane of the Solar System.

The orbits & current positions of Neptune, Pluto, and 2017 OF201. Jiaxuan Li & Sihao Cheng/Institute for Advanced Study.

2017 OF201 has a longitude of perihelion of 306° (i.e. it reaches perihelion at an angle of 306° relative to the First Point of Aries, taken as a celestial reference point). This is noteworthy, as many previously discovered trans-Neptunian objects have longitudes of perihelion clustered around 60°, something which has been postulated to imply the presence of a ninth planet (termed 'Planet X') in the Outer Solar System, the gravity of which is pushing the orbits of trans-Neptunian objects towards a similar trajectory. The orbit of 2017 OF201 not only shows no signs of such influence, it appears to be incompatible with such an object existing at all. This suggests that the similarity seen in the orbits of trans-Neptunian objects discovered to date is due to sampling bias - we have discovered more objects with longitudes of perihelion close to 60° because we have been looking at that part of the sky.

Plan view of the orbits of trens-Neptunian objects (TNOs) with extremely wide orbits, including our newly discovered 2017 OF201, which has a distinct orbit is an outlier to the apsidal clustering of the others. For reference, the most probable orbit of Planet X is shown in black. Cheng et al. (2025).

Analysis of light from 2017 OF201 suggests that it has a reddish hue, within the colour range of other trans-Neptunian objects, but possibly one of the redder objects. 2017 OF201 is calculated to be about 700 km in diameter, at which size it is presumed that it would be roughly spherical in shape. It is estimated to have a density of about 1.7 grams per cm squared, which would give it a total mass of about 300 000 000 000 000 megatons, or roughly one twenty thousandth the mass of the Earth.

2017 OF201 forms part of the Scattered Disk, an area between the Kuiper Belt considered to contain far less mass than either. However, if 2017 OF201, and other Scattered Disk objects, such as 90377 Sedna, represent an examples of a population of similar objects (which is a more likely explanation than all such objects currently being on the inner part of their orbits where we can detect them), then it is likely that the total mass contained in the Scattered Disk may be as high as 10% of that of the Earth, compared to 1-2% for the Kuiper Belt.

The orbits and positions of 2017 OF201 and 90377 Sedna. Wikimedia Commons.

2017 OF201 is unlikely to have formed on its current, highly eccentric, orbit. Rather, Cheng et al. estimate that it formed closer in to the Sun, on a more circular orbit, and has been moved onto its current orbit by encounters with other bodies. This orbit isnot consistent with the 'Planet X' hypothesis which has been used to explain the highly eccentric orbits of other trans-Neptunian objects.  Instead, Cheng et al. suggest that 2017 OF201 was initially knocked onto a less eccentric orbit by one or more encounters with the planet Neptune, and that that orbit has subsequently been further modified by the action of the Galactic Tides, and possibly close encounters with other steller systems.

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Duplexium jatobensis & Anhapoa munizi: Freshwater Mussels from the Early Cretaceous of northeastern Brazil.

Freshwater Mussels, Unionida, are the only order of Bivalves found exclusively in freshwater. There are about 900 species today, found on every continent, with some species considered economically significant, due to their use as food, their ability to produce pearls, their ability to modify environments, or their impact upon Fish stocks. Unionids have a unique life cycle among Bivalves, with a larval stage which lives commensually or parasitically on the skin, fins, or gills of a Fish host.

In a paper published in the Journal of South American Earth Sciences on 20 May 2025, Débora Eliza Baumann of the Laboratório de Paleontologia de Macroinvertebrados at São Paulo State University, Luiz Ricardo Simone of the Laboratório de Malacologia at the Museu de Zoologia of the Universidade de São Paulo, Rafael Costa da Silva of the Museu de Ciéncias da Terra of the Serviço Geológico do Brasil, and Renato Pirani Ghilardi, also of the Laboratório de Paleontologia de Macroinvertebrados at São Paulo State University, describe two new species of Unionid Freshwater Mussels from the Early Cretaceous Salvador Formation of Pernambuco State, Brazil.

The Salvador Formation outcrops in the Jatobá Basin of Pernambuco State, and records a fan delta laid down within a palaeolake in the Late Berriasian age (roughly between 140 and 137 million years ago). Both new species are described from specimens collected at a site designated BL-42 within the city of Floresta, and held within the collection of the Museu de Ciéncias da Terra of the Serviço Geológico do Brasil.

Location of Jatoba Basin (08◦30′ to 9◦06′ S; 37◦06′ to 38◦30′ W) in Northeast Brazil, location where the fossils are collected (8◦41′48.60″S 38◦16′34.30″W) and stratigraphy of the Jatoba Basin. Baumann et al. (2025).

The first new species is named Duplexium jatobensis, where 'Duplexium' refers to the fact that it has two types of teeth on its hinge, and 'jatobensis' means 'from Jatobá' in reference to the Jatobá Basin where it was discovered. The species is described from four specimens, which are between 47 and 50 mm in length, 18-19 mm in width, and 6-8 mm in thickness, with three teeth on the hinge, the central one of which is distinctly larger than the other two.

Holotype, MCT.I.7202. Duplexium jatobensis; Salvador Formation (Berriasian), general morphology and muscle scars. Abbreviations: aa, anterior adductor; pa, posterior adductor; pl, pallial line; ht, heterodont teeth; tt, taxodont teeth; pp, pedal protractor; apr, anterior pedal retractor; pe, pedal elevator; S1, posterior pedal retractor? S2, posterior adductor? or S1 + S2, slow and fast components of the posterior adductor? Scale bar is 10 mm. Baumann et al. (2025).

The second new species is named Anhapoa munizzi, where 'Anhapoa' derives from 'Anhapoā', which means 'canine tooth' in the Tupi-Guarani indigenous language of Brazil, in reference to a well-pronounced cardinal tooth on the hinge of the right valve of the shell. Anhapoa munizzi is described from five specimens, which range from 43 to 52 mm in length, 23 to 27 mm in width, and from 8 to 14 mm in thickness. The hinge of the right valve has a large cardinal tooth between two pits, and small lateral teeth.

Holotype, MCT.I.7147, Anhapoa munizi, Salvador Formation (Berriasian), general morphology and muscle scars. Abbreviations: aa, anterior adductor; pa, posterior adductor; pl, pallial line; ht, heterodont teeth; tt, taxodont teeth; pp, pedal protractor; apr, anterior pedal retractor; pe, pedal elevator, S1, posterior pedal retractor? S2, posterior adductor? or S1 + S2, slow and fast components of the posterior adductor? Scale bar is 10 mm. Baumann et al. (2025).

Both Duplexium jatobensis and Anhapoa munizi lack any form of ornamentation, have smooth beak, lack a prodissoconch, have a heterodont hinge and an additional taxodont hinge, have an elevator muscle scar, and lack a pallial sinus, all traits consistent with assignment to the Family Iridinidae within the Superfamily Etherioidea, one of the two major subdivisions of the Unionida.

The oldest members of the Family Iridinidae described to date come from the Middle Cretaceous of Africa, with some possible Iridinid fossils from the End Cretaceous of South America. Modern Iridinids are restricted to Africa, leading malacologists toconclude that the genus originated there, after the continents of Africa and South America split apart, between 140 and 120 million years ago. The Salvador Formation of the Jatobá Basin, however, was laid down during the earliest part of this rifting process, when Africa and South America were still joined, raising the possibility that the Iridinidae originated in South America, but died out there during the End Cretaceous Extinction.

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Ten miners confirmed dead, and a further ten missing following landslide in West Papua Province, Indonesia.

The bodies of ten miners have been recovered, and further ten are missing, following a landslide in the remote Arfak Mountains of West Papua Province, Indonesia, following a landslide on Friday16 may 2025. The landslide, which occurred at about 9.00pm, and is believed to have been triggered by heavy rains associated with the onset of the southwest monsoon, and struck a camp being used by artisanal gold miners. A further four miners were injured by the event, and rescue efforts are being hampered by the remote location of the site, which is ten hours travel from the nearest town, and ongoing heavy rains in the area.

Rescue workers battling floodwaters while recovering a body from a mining camp hit by a landslide in the emote Arfak Mountains of West Papua Province, Indonesia, on 16 May 2025. Indonesia Search and Rescue Agency/AFP).

Indonesia's large size, mineral richness, and poor population make unlicensed mining a widespread problem in the country, with illegal mines typically dug with hand tools and located in remote locations where authorities are unlikely to spot them (though some such operations are larger and more blatant in nature). Such mines tend to take few health and safety precautions, and are often dug by people with only a limited understanding of the structural geology of the area, making accidents extremely common, in many cases without help ever arriving due to the hidden nature of the mines. Such mines also present an environmental threat, producing waste which is often toxic, and contributing to deforestation, which can destabilise hillslopes, placing the miners at further risk.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry seasons, the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate.

Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

West Papua has two distinct Monsoon Seasons, with a Northeast Monsoon driven by winds from the South China Sea that lasts from November to February and a Southwest Monsoon driven by winds from the southern Indian Ocean from March to October. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest.

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Samaroblattella valmarensis: A Subioblattid 'roachoid' from the Middle Triassic of Monte San Giorgio fauna of Switzerland.

The Eoblattodea, or 'roachoids' form a stem group to the living Dictyoptera, which comprises the Cockroaches, Mantises, and Termites (a stem group contains fossil species more closely related to the living group they are on the 'stem' of than to any other living group, but not descended from the last common ancestor of all living members of that group). This stem group first appeared in the Carboniferous, with the common ancestor of all living Dictyopterans probably living in the Jurassic. The Subioblattids are a small group of 'roachoids' known from the Triassic of South Africa, France, and Central Asia. This group is fairly well-known from its forewing anatomy (the forewings are considered to be reliable on their own for the diagnosis of Insect relationships), but to date no body fossils found to date.

In a paper published in the Swiss Journal of Palaeontology on 10 March 2025, Matteo Montagna of the Department of Agricultural Sciences at the University of Naples Federico II, Fabio Magnani of the Museo Cantonale di Storia Naturale, Giulia Magoga, also of the Department of Agricultural Sciences at the University of Naples Federico II, and André Nel of the Institut de Systématique, Évolution, Biodiversité at the National d’Histoire Naturelle, describe a new species of Subioblattid 'roachoid' from the Middle Triassic of Monte San Giorgio fauna of Switzerland.

The Monte San Giorgio fauna derives its name from Monte San Giorgio, a mountain on the border between Italy and Switzerland in the Lugano Prealps. The exposed geological sequence on this mountain begins in the Lower Permian, where a succession of volcanic rocks mark the onset of the Variscan Orogeny, as the continents of Euramerica and Gondwana collided during the formation of the supercontinent of Pangea. These are overlain by a sequence of Triassic sediments recording a tropical terrestrial environment, a shallow near-shore environment, a deeper marine basin with extensive limestone deposits, a second terrestrial exposure caused by a major marine regression (drop in sealevel) in the Late Triassic, and finally an Early Jurassic marine Basin.

The fossils of the Monte San Giorgio fauna come from shales of the Besano Formation and the overlying Meride Limestone, which were laid down in the Early-Middle Triassic marine basin. These fossils include Bivalves, Marine Reptiles, Fish, Crustaceans, and Cephalopods, as well as terrestrial-derived fossils such as Plants, terrestrial Vertebrates, and Insects. To date, 273 species of Insect have been recorded from Monte San Giorgio, including Thrips, True Bugs, and Flies, as well as representatives of groups such as the Monura and Permithonidae, which were thought to hve died out in the End Permian Extinction until they were discovered here.

Location of the Monte San Giorgio UNESCO World Heritage Site and stratigraphic section of the Middle Triassic sediments. (A0 Map showing the location of Monte San Giorgio and the carbonate Anisian-Ladinian sequence and the location of Val Mara (indicated by a star) where VM 12 site occurs. (B) Stratigraphic section of Middle Triassic sediments in Monte San Giorgio; black arrow indincates the position of VM 12 strata where the Insect fossil was collected. Montagna et al. (2025).

The new species is described from a single specimen from Meride Limestone of Monte San Giorgio. This is placed in the genus Samaroblattella on the basis of its forewing veination, but assigned to a new species, valmarensis, meaning 'from Val Mara' in reference to the location where the fossil was found.

The genus Samaroblattella was first described in 1976 to describe a fossil from South Africa, with a second species described from Kazakhstan, Central Asia, in 2001. Unlike these previously described species, and indeed all other previously described members of the roachoid family Subioblattidae, to which the genus is assigned, Samaroblattella valmarensis has a preserved body as well as wings.

The hind legs of Samaroblattella valmarensisi closely resemble those of the extant Jumping Cockroach, Saltoblattella montistabularis, with both species also having an elongate shape, and a narrow pronotum (plate on the forepart of the prothorax, before the wings) suggesting that this ancient roachoid may have had a similar jumping habit. 

However, a close relationship is not proposed, as Samaroblattella valmarensisi also has an elongated, sword-like, external ovipositor, something absent from crown group Dictyopterans (ctown group comprises all species deecended from the last common ancestor of all living species), which have an internal ovipositor. External ovipositors were found in the earliest Insects, with internal ovipositors having appeared separately several times in different groups.

Holotype of Samaroblattella valmarensis. Arrows highlight specifc body parts: f, fore legs (femora)[ ml, mid legs (femora and tibiae); hl, hind legs (femora and tibiae); ce, cerci; ov, ovipositor. Scale bar is 5 mm. Montagna et al. (2025).

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Vesta at opposition.

Asteroid 4 Vesta will reach opposition (the point at which it is directly opposite the Sun when observed from the Earth) at 11.58 am GMT on Friday 2 May 2025, when it will also be at the closest point on its orbit to the Earth, 1.18 AU (i.e. 1.18 times as far from the Earth as the Sun, or about 176 825 000 km), and be completely illuminated by the Sun. While it is not obvious to the naked eye observer, asteroids have phases just like those of the Moon; being further from the Sun than the Earth, 4 Vesta is 'full' when directly opposite the Sun. As 4 Vesta is only about 525 km in diameter, it will not be visible to the naked eye, but with a maximum Apparent Magnitude (luminosity) of 5.7 at opposition, it should be visible in the Constellation of |Libra to viewers equipped with a good pair of binoculars or small telescope.

The orbit and position of 4 Vesta and the planets of the Inner Solar System 1t 12.00 noon GMT on Friday 2 May 2025.  JPL Small Body Database. 

4 Vesta has a 1326 day (3.63 year) orbital period and an eccentric orbit tilted at an angle of 7.14° to the plane of the Solar System, which takes it from 2.15 AU from the Sun (i.e. 215% of the average distance at which the Earth orbits the Sun) to 2.57 AU from the Sun (i.e. 257% of the average distance at which the Earth orbits the Sun). As an asteroid that never comes within 1.666 AU of the Sun and has an average orbital distance less than 3.2 AU from the Sun, 4 Vesta is classed as a Main Belt Asteroid. 

Asteroid 4 Vesta imaged by the Dawn space probe on 24 July 2011, from a distance of 5200 km. Björn Jónsson/NASA/JPL/MPS/DLR/IDA/Wikimedia Commons.

Asteroid 4 Vesta was discovered on 29 March 1807 by the German astronomer Heinrich Wilhelm Matthias Olbers, making it the fourth asteroid discovered, and the second by Olbers (who had discovered 2 Pallas on 28 March 1802). The asteroid was named Vesta in honour of the Roman goddess of the hearth. 4 Vesta is currently considered to be the second largest body in the Main Asteroid Belt, although uncertainty about the size of Asteroid 2 Pallas, means this is not completely certain.

Artist's concept of the Dawn space probe approaching 4 Vesta. NASA/JPL/CalTech.

The Dawn space probe orbited 4 Vesta from 16 July 2011 until 5 September 2012 (when it left to move on to Asteroid 1 Ceres). During this time it built up a detailed map of the surface of 4 Vesta, which revealed a northern surface covered with craters; apparently much older than the southern surface, suggesting that the asteroid was once a planetesimal on its way to growing into a planet.

High-resolution geological map of Vesta derived from Dawn spacecraft data. Brown colours represent the oldest, most heavily cratered surface. Purple colours in the north and light blue represent terrains modified by the Veneneia and Rheasilvia impacts, respectively. Light purples and dark blue colours below the equator represent the interior of the Rheasilvia and Veneneia basins. Greens and yellows represent relatively young landslides or other downhill movement and crater impact materials, respectively. NASA/JPL/CalTech/JSU.

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