Bright fireball meteor over Belgium.

Witnesses across much of Belgium, Luxembourg,and the Netherlands, as well as northern France, western Germany, and the southeast of England have reported observing a bright fireball 0.25 am local time on Wednesday 1 March 2023 (about 11.25 pm on Tuesday 28 February GMT). The fireball is described as having moved from south to north, entering the atmosphere to the south of Mons and disappearing somewhere around Brakel. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry.

The 1 March 2023 Belgian Meteorite from Beerse in Belgium. Lawrence Visser/American Meteor Society.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However, this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

Heat map showing areas where sightings of the meteor were reported (warmer colours indicate more sightings), and the apparent path of the object (blue arrow). American Meteor Society.

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Geckos from the Early Eocene Dormaal Site in Belgium.

The Middle and Late Eocene Lizard faunas of Europe are relatively well known, thanks to a number of lagerstätten (deposits with exceptional preservation) such as the Messel Shale of Germany. However, the Lizards of the Early Eocene are much less well understood, due to a paucity of such sites. This is unfortunate, as this interval starts with the Palaeocene-Eocene Thermal Maximum at 56 million  years ago, the which saw the warmest temperatures of the past 66 million years, with Northern Europe developing a sub-tropical to tropical climate, and therefore presumably being a particularly good environment for Lizards.

One exception to this lack of Early Eocene is the Dormaal locality at  Zoutleeuw, eastern Belgium, where a fluvial deposit comprised of layers of clayey and lignitic (coal-rich) sands are interbedded with lenses of grey clays. These deposits are thought to have been laid down in a system of rivers and lagoons in the earliest Eocene, and have yielded a diverse fauna of Mammals, Lizards, Fish, Turtles, and Crocodiles.

In a paper published in the journal Royal Society Open Science on 29 June 2022, Andrej Čerňanský of the Department of Ecology at Comenius University in Bratislava, Juan Daza of the Department of Biological Sciences at Sam Houston State University, Richard Smith of the Directorate Earth and History of Life at the Royal Belgian Institute of Natural Sciences, Aaron Bauer of the Department of Biology and Center for Biodiversity and Ecosystem Stewardship at Villanova University, Thierry Smith, also of the Directorate Earth and History of Life at the Royal Belgian Institute of Natural Sciences, and Annelise Folie of the Scientific Survey of Heritage at the Royal Belgian Institute of Natural Sciences, describe A new species of Gacko from the Dormaal Site.

Location of the earliest Eocene locality of Dormaal (MP7, Belgium) that has yielded Dollogekko dormaalensis and the early Eocene locality of Prémontré (MP10, France) that has yielded Laonogekko lefevrei. Čerňanský et al. (2022).

Geckos as a group have a poor fossil record, due to their lightly mineralised and easily disarticulated skeletons. The oldest known Geckos come from the Early Cretaceous amber deposits of Myanmar, with Geckos also known from Eocene Baltic Amber and Miocene Dominican Amber. Outside of these amber deposits, however, almost all fossil Geckos are known from isolated skeletal elements. Geckos have previously been recorded from the Dormaal locality, but never actually formally described.

The new species is named Dollogekko dormaalensis, where 'Dollogekko' honours the prominent Belgian palaeontologist Louis Dollo (1857-1931), combined with '-gekko' the Malay root word of the English 'gecko', often used as a suffix for generic names within the group, and 'dormaalensis' means 'from Dormaal'. The species is described from a single incomplete frontal bone (the bone that forms the forehead in Humans).

Dollogekko dormaalensis, the holotypic frontal IRSNB R 452 in (a) dorsal, (b) ventral, (c) right lateral,(d) left lateral and (e) anterior views. Čerňanský et al. (2022).

The frontal bones of Geckos tend to be highly distinctive at the species level, making it possible to reliably describe new taxa on these bones alone. The specimen from which Dollogekko dormaalensis is described comprises about the anterior half of the frontal bone, with the posterior half being lost. The preserved portion is 4.3 mm in length, is tubular-to-funnel-shaped (the whole bone would almost certainly have been hourglass shaped), and would have extended about ¾ of the way around the orbit. 

Dorsal view of the skull of some extant Geckos exhibiting diversity of frontal bone shape and sculpturing (yellow). (a) Carphodactylidae, Underwoodisaurus  milii (CAS  74744),  (b)  Diplodactylidae, Rhacodactylus  leachianus (MCZ–R15967), (c) Phyllodactylidae, Thecadactylus rapicauda (CAS 95146) and (d) Gekkonidae, Chondrodactylus angulifer (CAS 126466). Čerňanský et al. (2022).

In addition to the partial frontal from which Dollogekko dormaalensis is described, Čerňanský et al. also describe two fragments of dentary and a partial mandible from the same deposit. The dentary fragments appear to be from a Gecko about the same size as Dollogekko dormaalensis, while the partial mandible appears to come from an Animal about twice the size. Since the frontal bone from which Dollogekko dormaalensis is described is fully fused, and therefore presumed to come from an adult individual which has stopped growing, this appears likely to represent a separate species. The dentary fragments are of a size compatible with he frontal bone, but it is impossible to confirm that they belong to the same species, derive from a juvenile of the species which produced the mandible, or represent a third species. Due to this uncertainty, and the low value of mandible fragments for taxonomic purposes, none of these specimens are named, but instead referred to as Gekkota indet 1 (dentaries) and Gekkota indet 2 (mandible).

Gekkota indet. 1, the dentaries IRSNB R 454 and IRSNB R 453; Gekkota indet. 2, the mandible fragment IRSNB R 456 in(a), (e), (i) lateral, (b), (f), (j) medial, (c), (g), (k) dorsal, (d) ventral and (h) anterior views. Čerňanský et al. (2022).

See also...

Online courses in Palaeontology. 

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.

Estimating the benefits of agroforestry to European wildlife.

The term agroforestry is used to denote practices in which the cultivation of trees is integrated either with the rearing of livestock (in which case it is called silvopasturalism) or other plant crops (silvoarablism). This is a traditional practice across much of Europe, where methods such as grazing livestock in orchards are very widespread, with newer methods being developed more recently, such as short-rotation coppicing being carried out alongside rows of other crops. Systems in which productive trees are grown around the edges of fields are also sometimes considered to be agroforestry, although in these cases the trees are managed separately to the other produce, and may be under separate ownership.

 

Pigs grazing in an open Oak forest system in Spain, a system known as a 'dehesa'. Álvarez (2016).

Europe has suffered particularly severe losses of biodiversity compared to other parts of the world, and this is particularly severe in areas where intensive agriculture is prevalent. Agroforestry promotes a more diverse landscape than arable monoculture, potentially resulting in higher biodiversity. Quantifying the benefits of this could potentially lead to the system being more heavily prioritised under the European Common Agricultural Policy or any successor system.

Agroforestry systems have been well studied in tropical environments, where the evidence suggests that the system offers significant advantages in biodiversity preservation over intensive monocultural systems, but nevertheless tends to lead to reduced biodiversity compared to both primary and secondary forests. The system is less well studied in temperate regions, with most studies tending to concentrate on single groups of Animals, such as Birds or Insects. This leaves the benefits of such systems in Europe somewhat unclear, particularly as the definitions of agroforestry can vary, leading to differences in what systems are included in studies, making comparisons between studies difficult. 

 

Hazel short rotation coppice system alongside crops in Suffolk, UK. Smith et al. (2014).

In a paper published in the journal BMC Ecology and Evolution on 23 October 2021, Anne‑Christine Mupepele of Nature Conservation and Landscape Ecology and Biometry and Environmental System Analysis at the University of Freiburg, and Matteo Keller and Carsten Dormann, also of Environmental System Analysis at the University of Freiburg, present the results of a meta-analysis which combined results from a number of studies of agroforestry systems across Europe.

Mupepele et al. sought to answer three questions, 'What is the effect of agroforestry on biodiversity relative to forests, pastures, cropland or abandoned, shrub-encroached agroforestry?', 'Is the effect of agroforestry on biodiversity influenced by environmental variables, specifically the kind of agroforestry system (silvopasture or silvoarable), sampling method, the specific measure of biodiversity, sampling year, country, climate and the reference used?' and 'How strong and robust is the underlying evidence of these results?'

To which end they located 1411 previous studies of agroforestry systems in Europe, 50 of which were eventually included in the study, representing 69 individual agroforestry sites. Each of these had a direct comparison of a type of agroforestry (silvoarable or silvopastoral) to forests, cropland, pasture, and/or abandoned agroforestry systems.

 

Map of Europe with the number of effect sites per country. Mupepele et al. (2021).

The studies included in the analysis covered sites across Europe where agroforestry systems have been studied between 1984 and 2019. The majority of these sites were caried out in Iberia and the Mediterranean region, with twelve studies from Spain, eight from Portugal, five from Italy, one from France and one from Turkey. Temperate central Europe was represented by six studies from the UK, four from Romania, two each from France, Germany, and Switzerland, and one each from Belgium and northern Italy. The northern boreal region was represented by four studies from Sweden and two from Finland.

Thirty six of the included studies looked at silvopastoral systems, with thirty six studies looking at 52 sites, while silvoarable systems were the subject of thirteen studies looking at seventeen sites. The biodiversity of agroforestry was most commonly compared to that of pasture (23 sites), or forests (21 sites), then abandoned agroforestry systems (thirteen sites) and cropland (12 sites).

 

Sheep grazing in a plantation of Pine and Eucalyptus in Spain. Monica Pelliccia/Mongabay.

The different studies measured biodiversity in different ways, and concentrated on different groups. In order to make a comparison between these diverse studies, Mupepele et al. divided the measured wildlife into five groups, Arthropods, Birds, Bats, Plants, and 'Fungi plus Lichens and Bryophytes', Most of the included studies measured biodiversity at the 'species richness level', although other measures were used.

Mupepelele et al.'s results showed no overall benefit for biodiversity compared to the average derived from all systems. However, silvoarable systems were found to host considerably more biodiversity than other croplands, although they generally hosted less biodiversity than forests. Silvopastoral systems produced less clear results, with measures often producing conflicting results in different studies (i.e. one study might show higher Avian biodiversity in a silvopastoral system than a forest, while another showed the reverse.

Birds and Artropods were typically found at higher levels of diversity in agroforestry envoronments than other systems, Where the original group sorted Arthropods into different groups (e.g. Bees, Beetles and Spiders', then this biodiversity increassed, although this was across all environments, with no change in the beneficial effect of agroforestry.

 

Cereal crops grown alongside trees in Bedfordshire, UK. Agroforestry Research Trust.

Mupepele et al. note that the quality of the studies they were referencing varied somewhat, with some using replicated experimentation with clear controls, whilst others were more observational in nature. To compensate for this, they tried applying a statistical weighting method that gave more value to the more statistically strong studies, but found this made no difference to the overall result. They also carried out funnel plot and Egger’s regression tests for undetected biases in their data, but did not find bias was a problem.

A previous  meta-analysis led by Mario Torralba of the Department of Geosciences and Natural Resource Management at the University of Copenhagen found that agroforestry had a much stronger impact on biodiversity, which caused Mupepele et al. to consider the differences between their findings and that of the earlier study. They note that Torralba et al.'s study was published in 2016, and contained the results from two studies published in 2015 on the benefits of agroforestry in Mediterranean ecosystems, both of which produced very strong positive results, and that if these were excluded from Torrialba et al.'s data then the result was closer to that of Mupepele et al. who included several post 2015 studies with less clear results.

Properly done, meta-analyses can provide a powerful tool for understanding ecological systems in ways not possible from individual studies or unsystematic literature searches. However, the robustness of these results is dependent on the methods used to analyse the data, and in particular the use of weighting to take into account the quality of the studies being referenced. This needs to be done carefully, as failure to apply the right weighting can often lead to very different results. This said, applying weighting to Mupepele et al.'s results resulted in no significant change in the outcome of the study, which strongly supports the robustness of their findings. 

The application of repeated meta-analyses to the same data set can reveal changes over time, as new studies add to the overall picture, dampening the results from atypical studies that might have a profound impact on a smaller data-set. By building a cumulative model in which data were added in chronological order, Mupepele et al. were able to demonstrate that the impact of agroforestry upon biodiversity remained essentially unchanged over time, despite the presence of some anomalous data. They do, however, note that silvoarable systems make up a relatively small proportion of the whole, and that the addition of a higher proportion of studies of these systems in future might change the results of the meta-analysis.

 

Merino Sheep under a Cork Oak in a montado silvopastoral system in Portugal. European Agroforestry Foundation.

The ability to reproduce results is an important principle in science, but can be difficult in fields like ecology, which look at complex natural systems, no two of which are ever completely the same. Mupepele et al.'s results differed strongly from the earlier results of Torralba et al., resulting in their drawing different conclusions; Torralba et al. concluded that agroforestry has a general positive impact upon biodiversity, while Mupepele et al. concluded that this benefit was only clear when agroforestry was compared to croplands, despite both studies having used much of the same data. Mupepele et al. note that Torralba et al. included hedgerows and woody riparian buffers to agricultural land as agroforestry, while Mupepele et al. excluded them on the basis that they are not emplaced for silvicultural purposes (i.e. the trees used in these settings are grown for their value as boundaries, not as a crop in themselves). Neither did Torralba et al. include data from studies which suggested agroforestry had a negative impact on biodiversity. Mupepele et al. believe that scientists should be very clear about what data they are including in meta-analyses, the criteria for choosing this data, and the reasons to do so, in order to help policy-makers judge the significance of different studies. 

Mupepele et al. conclude that silvoarable systems produce an increase in biodiversity compared to conventional croplands, particularly with regard to Birds and Arthropods, but that this increase is not large, and there was no overall positive benefit of agroforestry to all other settings. Notably, silvopasturalism showed no clear benefit over either forestry or conventional pasturelands. Where previous studies have produced enthusiastic support for agroforestry, and strongly suggested these systems are linked to a significant increase in biodiversity, Mupepele take a more cautious approach, noting that relatively few studies find an unqualified link between agroforestry and increased biodiversity, and that literature reviews and meta-analyses need to be careful to include both the positive and negative impacts of systems when drawing on data from multiple studies. Nevertheless, they do conclude that agroforestry can have a positive impact on biodiversity under some circumstances, as well as providing carbon sequestration and other ecosystem services, and that a better understanding of how these systems work could lead to more informed future decisions by policy makers.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter. 

 

UNESCO adds seven new sites to its World Herritage List.

The United Nations Educational, Scientific, and Cultural Organisation (UNESCO) has added seven new sites to its World Herritage List, according to a press release issued on 26 July 2021. Four of these sites have been added for their natural herritage: Amami-Oshima Island, Tokunoshima Island, northern part of Okinawa Island, and Iriomote Island (Japan), Getbol, Korean Tidal Flats (Republic of Korea), Kaeng Krachan Forest Complex (Thailand) and Colchic Rainforests and Wetlands (Georgia); while three have been added for the cultural significance: Arslantepe Mound (Turkey), Extension of Defence Lines of Amsterdam, henceforth to be known as Dutch Water Defence Lines (Netherlands) and the transnational site of Colonies of Benevolence (Belgium and Netherlands).

The Amami-Oshima Island, Tokunoshima Island, northern part of Okinawa Island, and Iriomote Island site emcompasses 427 km² of subtropical rainforests on four islands on a chain located in the southwest of Japan, the serial site forms an arc on the boundary of the East China Sea and Philippine Sea whose highest point, Mount Yuwandake on Amami-Oshima Island, rises 694 metres above sea level. Entirely uninhabited by Humans, the site has high biodiversity value with a very high percentage of endemic species, many of them globally threatened. The site is home to endemic Plants, Mammals, Birds, Reptiles, Amphibians, inland water Fish and Decapod Crustaceans, including, for example, the endangered Amami Rabbit, Pentalagus furnessi, and the endangered Ryukyu Long-haired Rat, Diplothrix legata, that represent ancient lineages and have no living relatives anywhere in the world. Five Mammal species, three Bird species, and three Amphibian species in the property have been identified globally as Evolutionarily Distinct and Globally Endangered (EDGE) species. There are also a number of different endemic species confined to each respective island that are not found elsewhere in the site.

 

Mangrove forest (Nakama River, Iriomote Island), of the World Heritage site 'Amami-Oshima Island, Tokunoshima Island, northern part of Okinawa Island, and Iriomote Island'. Ministry of the Environmen, Japan.

The Getbol Tidal Flats of Korea are situated in the eastern Yellow Sea on the southwestern and southern coast of the Republic of Korea, the site comprises four component parts: Seocheon Getbol, Gochang Getbol, Shinan Getbol and Boseong-Suncheon Getbol. The site exhibits a complex combination of geological, oceanographic and climatologic conditions that have led to the development of coastal diverse sedimentary systems. Each component represents one of four tidal flat subtypes (estuarine type, open embayed type, archipelago type and semi-enclosed type). The site hosts high levels of biodiversity, with reports of 2150 species of flora and fauna, including 22 globally threatened or near-threatened species. It is home to 47 endemic and five endangered marine invertebrate species besides a total of 118 migratory Bird species for which the site provides critical habitats. Endemic fauna includes Mud Octopus, Octopus minor, and deposit feeders like Japanese Mud Crabs, Macrophthalmus japonica, Fiddler Crabs, Uca lactea, and Polychaetes (Bristle Worms), Stimpson’s Ghost Crabs, Ocypode stimpsoni, Yellow Sea Sand Snails, Umbonium thomasi, as well as various suspension feeders like Clams. The site demonstrates the link between geodiversity and biodiversity, and demonstrates the dependence of cultural diversity and Human activity on the natural environment.

 

Autumn in Suncheonman Bay. World Heritage Promotion Team of the Korean Tidal Flats.

The Kaeng Krachan Forest Complex of Thailand is located along the Thailand side of the Tenasserim mountain range, part of a north-south granite and limestone mountain ridge running down the Malay Peninsula. Located at the cross-roads between the Himalayan, Indochina, and Sumatran faunal and floral realms, the property is home to rich biodiversity. It is dominated by semi-evergreen/dry evergreen and moist evergreen forest with some mixed deciduous forest, montane forest, and deciduous Dipterocarp forest. A number of endemic and globally endangered plant species have been reported in the property, which overlaps with two Important Bird Areas and is noted for its rich diversity of Birdlife, including eight globally threatened species. The lpcality is home to the critically endangered Siamese Crocodile, Crocodylus siamensis, the endangered Asiatic Wild Dog, Cuon alpinus, Banteng, Bos javanicus, Asian Elephant, Elephas maximus, Yellow/Elongated Tortoise, Indotestudo elongata, and the endangered Asian Giant Tortoise, Manouria emys, as well as several other vulnerable species of Birds and Mammals. Remarkably, it is also home to eight Cat species: the endangered Tiger, Panthera tigris, and Fishing Cat, Prionailurus viverrinus, near-threatened Leopard, Panthera pardus, and Asian Golden Cat, Catopuma temminckii, the vulnerable Clouded Leopard, Neofelis nebulosi, and Marbled Cat, Pardofelis marmorata, as well as Jungle Cat, Felis chaus, and Leopard Cat, Prionailurus bengalensis. 

 

Kaeng Krachan Forest Complex. Department of National Parks, Thailand.

The International Union for the Conservation of Nature has acknowledged the World Heritage Committee’s decision to inscribe the Kaeng Krachan Forest Complex onto the World Heritage List, and the commitment expressed by the Government of Thailand to continue the work in progress relating to the site. The organisation has expressed willingness to support the Thai Government in its work with local communities and other concerned stakeholders to address the Committee’s decision, and uphold the World Heritage Convention’s own policies and high standards of conservation practice. However, it has also raised concerns about Human rights issues around the site which have yet to be resolved, in particular the need for indigenous Karen communities to provide their consent, and for their concerns to be resolved.

 

Kaeng Krachan Forest Complex. Sunee Sakseau/Department of National Parks, Thailand.

The International Union for the Conservation of Nature further states that respecting the rights of indigenous peoples and local communities in conservation is a clearly stated policy of the World Heritage Convention and is central to the International Union for the Conservation of Nature mission and values. The International Union for the Conservation of Nature’s membership, composed of government, civil society and indigenous peoples’ organisations, sets the policies that guide the International Union for the Conservation of Nature’s wider work. In this regard, The International Union for the Conservation of Nature’s Resolutions emphasise that nature conservation must respect the rights of indigenous peoples to the territories they have traditionally owned and used.

 

Herd of Gaurs, Bos gaurus, in the Kaeng Krachan Forest Complex. Sunee Sakseau/Department of National Parks, Thailand.

The Colchic Rainforests and Wetlands of Georgia site comprises seven component parts, within an 80 km long corridor along the warm-temperate and extremely humid eastern coast of the Black Sea. They provide a series of the most typical Colchic ecosystems at altitudes ranging from sea level to more than 2500 metres above it. The main ecosystems are ancient deciduous Colchic rainforests and wetlands, percolation bogs and other mire types of the distinct Colchic mire region. The extremely humid broad-leaved rainforests comprise a highly diverse flora and fauna, with very high densities of endemic and relict species, with significant numbers of globally threatened species and relict species, which survived the glacial cycles of the Tertiary. The site is home to approximately 1100 species of Vascular and non-Vascular Plants, including 44 threatened Vascular Plant species, and almost 500 species of Vertebrates, and a high number of Invertebrate species. The site also harbours 19 threatened Animal species including Sturgeon, notably the critically endangered Colchic Sturgeon, Acipenser persicus. It is a key stopover for many globally threatened Birds that migrate through the Batumi bottleneck.

 

Kolkheti National Park in Churia District, Georgia: visitor center and Bird-watching tower. Agency of Protected Areas of Georgia.

Arslantepe Mound is a 30-metre-tall archaeological tell located in the Malatya plain, 12 km south-west of the Euphrates River in Anatolian Turkey. Archaeological evidence from the site testifies to its occupation from at least the 6th millennium BC up until the late Roman period. The earliest layers of the Early Uruk period are characterized by adobe houses from the first half of the 4th millennium BC. The most prominent and flourishing period of the site was in the Late Chalcolithic period, during which the so-called palace complex was constructed. Considerable evidence also testifies to the Early Bronze Age period, most prominently identified by the Royal Tomb complex. The archaeological stratigraphy then extends to the Paleo-Assyrian and Hittite periods, including Neo-Hittite levels. The site illustrates the processes which led to the emergence of a State society in the Near East and a sophisticated bureaucratic system that predates writing. Exceptional metal objects and weapons have been excavated at the site, among them the earliest swords so far known in the world, which suggests the beginning of forms of organized combat as the prerogative of an elite, who exhibited them as instruments of their new political power.

 

Overview of Arslantepe mound in the Orduzu plain. MAIAO.

The Dutch Water Defence Lines represents a defence system extending over 200 km along the edge of the administrative and economic heartland of Holland. It is comprised of the New Dutch Waterline and the Defence Line of Amsterdam. Built between 1815 and 1940, the system consists of a network of forts, dikes, sluices, pumping stations, canals and inundation polders, working in concert to protect the Netherlands by applying the principle of temporary flooding of the land. It has been developed thanks to the special knowledge of hydraulic engineering for defence purposes held and applied by the people of the Netherlands since the 16th century. Each of the polders along the line of fortifications has its own inundation facilities.

 

Dutch Water Defence Lines (extension of the Defence Line of Amsterdam). Fortified town of Gorinchem. New Dutch Waterline.

The transnational Colonies of Benevolence encompasses four settlements; cultural landscapes with one colony in Belgium and three in The Netherlands. Together they bear witness to a 19th century experiment in social reform, an effort to alleviate urban poverty by establishing agricultural colonies in remote locations. Established in 1818, Frederiksoord (the Netherlands) is the earliest of these colonies and home to the original headquarters of the Society of Benevolence, an association which aimed to reduce poverty at the national level. Other components of the property are the colonies of Wilhelminaoord and Veenhuizen, in the Netherlands, and Wortel in Belgium. As the colonies’ small farms yielded insufficient revenues, the Society of Benevolence sought other sources of revenue, contracting with the State to settle orphans, soon followed by beggars and vagrants, leading to the creation of 'unfree' colonies, such as Veenhuizen, with large dormitory type structures and larger centralised farms for them to work under the supervision of guards. The colonies were designed as panoptic settlements along orthogonal lines. They feature residential buildings, farm houses, churches and other communal facilities. At their peak in the mid-19th century, over 11 000 people lived in such colonies in the Netherlands. In Belgium their number peaked at 6000 in 1910. 

 

Frederiksoord Colony of Benevolence. Province of Drenthe.

See also...

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter. 

Fireball meteor over the Low Countries.

Witnesses across the Netherlands, Belgium, England, and northern France, have reported observing a bright fireball slightly after 6.50 am local time GMT on Friday 22 January 2021. The fireball is described as having moved from north to south, appearing over the Schelde Estuary and passing between the cities of Antwerp and Gent. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry. 

 

The 22 January 2021 fireball meteor seen from Almere in the Netherlands. Timo De Frys/American Meteor Society.

 

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However, this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

 

Heat map of northwest Europe showing areas where sightings of the meteor were reported (warmer colours indicate more sightings), and the apparent path of the object (blue arrow). American Meteor Society.

 

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

 

The 22 January 2021 fireball as recorded by the Fireball Recovery and InterPlanetary Observation Network camera at Oostkapelle, the Netherlands. FRIPON/Meteor News.

 

The meteor was first detected at an altitude of about 70 km and disappeared at an altitude of about 27 km, which would indicate an initial object with an approximate equivalent diameter of 25 m (i.e. it can be estimated that a spherical object with the same volume would be 25 m in diameter), and had an initial velocity of about 16 km per second, decelerating to about 8 km per second before disappearing, according to the Fireball Recovery and InterPlanetary Observation Network. This makes it highly likely that fragments of the object may have reached the ground. 

 

The trajectory of the 22 January 2021 meteor above Belgium. FRIPON/Meteor News.

Based upon this information, Simon Jean of the Observatoire de Paris has estimate that the object would have had an original orbit tilted at an angle of 20.1° to the plain of the Solar System, which took it from 0.96 AU from the Sun (96% of the distance at which the Earth orbits the Sun) and a semi-major axis (average distance form the Sun of 1.28 (128% of the distance at which the Earth orbits the Sun). Such an object would have been classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer).

 

The estimated original orbit of the 22 January 2021 meteor. FRIPON/Meteor News.

 

See also...

 

Follow Sciency Thoughts on Facebook.

Follow Sciency Thoughts on Twitter.