Tuesday, 21 November 2017

Asteroid 2017 VN13 passes the Earth.

Asteroid 2017 VN13 passed by the Earth at a distance of about 1 141 000 km (2.97 times the average distance between the Earth and the Moon,  or 0.76% of the distance between the Earth and the Sun), slightly before 8.30 pm GMT on Wednesday 15 November 2017. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2017 VN13 has an estimated equivalent diameter of 4-16 m (i.e. it is estimated that a spherical object with the same volume would be 4-16 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) in the atmosphere between 43 and 25 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2017 VN13. Minor Planet Center.

2017 VN13 was discovered on 14 November 2017 (the day before its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2017 VN13 implies that the asteroid was the 288th object (object N13) discovered in the first half of November 2017 (period 2017 V).

2017 VN15 has a 813 day orbital period and an eccentric orbit tilted at an angle of 5.44° to the plane of the Solar System, which takes it from 0.93 AU from the Sun (i.e. 93% of he average distance at which the Earth orbits the Sun) to 2.48 AU from the Sun (i.e. 248% of the average distance at which the Earth orbits the Sun, more than the distance at which the planet Mars orbits). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that 2017 VN13 has occasional close encounters with the planet Mars, which it is next predicted to pass in May 2029.

See also...

http://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-vf14-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-vv12-passes-earth.html


http://sciencythoughts.blogspot.co.uk/2017/11/the-leonid-meteors.html
http://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-wd-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-vd-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2017/11/fragments-of-metorite-found-in-british.html

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Extensive Coraline Algal Reef discovered on the coast of northern Taiwan.

The tropical seas are noted for their extensive Coral Reef systems, though Corals are far from being the only reef-forming organisms in the seas. Coraline Algae are Rhodophytes (Red Algae) that form extensive reef systems in temperate waters, though they are seldom observed as they favour nutrient rich waters (which tend to be opaque) and depths of greater than 10 m. Algal Reefs also occur in tropical and sub-tropical environments, though they are much less common here, typically only being found in areas of high sedimentation, which excludes most Coral species.

In a paper published in the journal Coral Reefs on 20 September 2017, Ching-Yu Liou of the Endemic Species Research Institute, and Sung-Yin Yang and Chaolun Allen Chen of the Biodiversity Research Center at Academia Sinica, report the discovery of an extensive Coralline Algal Reef system the coastline of Taoyuan City in northwest Taiwan.

The reef covers an area about 27 km long and 450 m wide, in an area with a tidal range of about 4 m, exposing much of the reef at low tides. It has a porous structure, being made up of stacked layers of Algae, predominantly of the genera Mesophyllum, Phymatolithon, and Harveylithon, as well as sediment-tolerant Corals such as Cyphastrea and Dipsastraea. Carbon-dating of drilled cores from the Reef suggests it began to form about 7500 years ago.

Coraline Algal Reef during low tide with windmills in the background. Liou et al. (2017).

Liou et al. suggest that the Taoyuan Reef is likely to perform similar ecosystem services to similar sized Coral Reef systems, and note that it is home to little-known and probably rare species such as the newly discovered Coral Polycanthus chaishanensis, and at least two species of as yet undescribed Corals. They also note that it is threatened by coastal developments in the area, including a planned industrial park and wind farm. 

Detail of a section of the Reef showing undescribed Crustose Coraline Algal species, Phymatolithon sp. nov. (left) and Mesophyllum sp. nov. (right). Liou et al. (2017).

See also...

http://sciencythoughts.blogspot.co.uk/2017/11/hundreds-of-green-sea-turtles-found.htmlhttp://sciencythoughts.blogspot.co.uk/2017/10/algal-bloom-covers-much-of-western-lake.html
http://sciencythoughts.blogspot.co.uk/2016/05/multicellular-eukaryotic-organisms-from.htmlhttp://sciencythoughts.blogspot.co.uk/2016/05/extensive-reef-system-discovered-around.html
http://sciencythoughts.blogspot.co.uk/2014/05/a-phytomyxean-parasite-forming-galls-on.htmlhttp://sciencythoughts.blogspot.co.uk/2014/05/a-phytomyxean-parasite-forming-galls-on.html
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Spilosmylus spilopteryx & Spilosmylus tephrodestigma: Two new species of Osmylid Lacewing from Luzon Island, the Philippines.

Osmylids (Osmylidae) are a group of Neuropteran Insects with a fossil record dating back to the Early Jurassic, with a stem group lineage (i.e. fossils of species more closely related to them than to anything else, but not descended from the last common ancestor of all living species), that are still in existence today. They appear to have been at their most numerous and diverse in the Middle-Late Jurassic, with a number of lineages apparently disappearing at the Jurassic-Cretaceous boundary.Living Osmylids tend to be large, and often have strongly patterned wings. Their larvae have elongated, lance-like mandibles, giving the group the alternative name 'Lance Lacewings'.

In a paper published in the journal ZooKeys on 26 October 2017, Davide Badano of the Dipartimento di Scienze della Terra at the Università degli Studi di Genova, and Shaun Winterton of the California State Collection of Arthropods, describe two new species of Osmylids from Luzon Island in the Philippines. Both are placed in the genus Spilosmylus, which is found from East Africa across South and Southeast Asia and as far east as Australia. 

The first new species is named Spilosmylus spilopteryx, where 'spilopteryx' means 'marked wing' in reference to the prominent, cloud-like markings in its wings. It is described from a single male specimen collected from the Tigaon area of Camarines Sur Province on southern Luzon. It is 10.48 mm in length, with a forewing length of 17.46 mm, and brown in colour with distinctively marked wings.

Spilosmylus spilopteryx, male specimen in dorsal view. Badano & Winterton (2017).

The second new species is named Spilosmylus tephrodestigma, where 'tephrodestigma' means 'coal spot' in reference to the grey spots found on its forewings. This species is described from a single specimen from the Barlig area of Mountain Province on northern Luzon Island. This specimen has a damaged abdomen, making it impossible to determine its sex or body length, but it has a forewing length of 21.43 mm, and is pale in colour with brown markings on its body and grey markings on its wings.

Spilosmylus tephrodestigma, specimen in dorsal view. Badano & Winterton (2017).

See also...

http://sciencythoughts.blogspot.co.uk/2017/09/lithochrysa-borealis-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/08/cretaconiopteryx-grandis-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2017/07/parababinskaia-elegans-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2016/11/lasiosmylus-longus-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2016/08/paleosisyra-minor-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2016/02/butterflies-of-jurassic-convergent.html
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Magnitude 5.9 Earthquake beneath Posi Posi Rao Island, North Maluku Province, Indonesia.

The United States Geological Survey recorded a Magnitude 5.9 Earthquake at a depth of 20.3km, beneath the northern part of Posi Posi Rao Island in the North Maluku Province of Indonesia, slightly slightly after 1.05 am local time on Sunday 19 November 2017 (slightly after 4.05 pm on Saturday 18 November, GMT). There are no reports of any casualties associated with this event, but it did cause some minor damage to buildings in Posiposi village, on the south part of the island.

Damage to buildings on Posiposi Rao Island following the 19 Novenmber 2017 Earthquake. Earthquake Report.

Posiposi Rao lies at the northern end of the Halmahera Islands chain, a volcanic arc formed where one tectonic plate is being subducted beneath another, with the underlying plate being melted by the heat of the Earth's interior, and lighter minerals bubbling up through the overlying plate to form volcanoes. However the Halmahera Islands are unusual in that they lie on a double subduction zone. The underlying plate, a northeaster extension of the Molucca Sea Plate, is being overridden form the Philippine Plate from the east and the Eurasian Plate from the west. The Halmahera volcanoes are located where the Philippine Plate is overriding the Molucca Sea Plate; to the west the Sangihe Islands lie where the Molucca Sea Plate is being overridden by the Eurasian Plate.

 Diagrammatic representation of the subduction zones beneath Halmahera (middle), plus the Philippines (top) and Sulawesi (bottom), with the Eurasian Plate to the left, the Molucca Sea Plate in the middle, and the Philippine Plate to the right.  Hall & Wilson (2000).

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

The approximate location of the 19 November 2017 Posiposi Rao Earthquake. USGS.

See also...

http://sciencythoughts.blogspot.co.uk/2017/09/eruptions-on-mount-ibu-halmahera.htmlhttp://sciencythoughts.blogspot.co.uk/2013/11/magnitude-62-earthquake-off-north-coast.html
http://sciencythoughts.blogspot.co.uk/2013/10/eruptions-on-mount-dukono-on-halmahera.htmlhttp://sciencythoughts.blogspot.co.uk/2013/09/eruptions-on-mount-dukono.html
http://sciencythoughts.blogspot.co.uk/2012/09/eruption-on-gamalama.htmlhttp://sciencythoughts.blogspot.co.uk/2011/12/volcanic-activity-in-halmahera-islands.html
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Coelogyne magnifica: A new species of Orchid from Kachin State, Myanmar.

Epidendroid Orchids, Epidendroideae, are the largest subfamily of Orchids, with over 15 000 described species, more than all other Orchid groups combined. The majority of these species are epiphytic (live on other plants, typically in the canopy of rainforest trees), though terrestrial forms are known. The group is found across the globe, with the exception of the polar regions, the deserts of Africa, Arabia and Australia, and the southern part of South America. The genus Coelogyne contains about 200 species predominately found in South and Southeast Asia, as well as on the islands of the Pacific as far east as Fiji and Samoa.

In a paper published in the journal PhytoKeys on 12 October 2017, Bin Yang and Shi-Shun Zhou of the Southeast Asia Biodiversity Research Institute of the Chinese Academy of Sciences, and the Centre for Integrative Conservation at the Xishuangbanna Tropical Botanical Garden, Qiang Liu, also of the Southeast Asia Biodiversity Research Institute of the Chinese Academy of Sciences, and of the Gardening and Horticulture Department at the Xishuangbanna Tropical Botanical Garden, Kyaw Win Maung of the Forest Research Institute of the Ministry of Environmental Conservation and Forestry in Myanmar, Ren Li, also of the Southeast Asia Biodiversity Research Institute of the Chinese Academy of Sciences, and Rui-Chang Quan and Yun-Hong Tan, agian of the Southeast Asia Biodiversity Research Institute of the Chinese Academy of Sciences, and the Centre for Integrative Conservation at the Xishuangbanna Tropical Botanical Garden, describe a new species of Coelogyne from the Hponkanrazi Wildlife Sanctuary in Kachin State, Myanmar.

The new species is named Coelogyne magnifica, in reference to its large, attractive flowers. It is an epiphytic or lithophytic herb (small plant growing on other plants or exposed rocks) reaching 11-15 cm in height, producing clusters of large, fleshy, white flowers in April and May and fruit in June and July.

Coelogyne magnifica, wild specimen in flower. Yang et al. (2017).

Three populations of these Orchids were found, all growing within the Hponkanrazi Wildlife Sanctuary in Kachin State, at altitudes of about 2450 m. All locations were rather inaccessible, and showed no sign of any Human molestation, for which reason Yang et al. do not believe the species to be under any current conservation threat.

Coelogyne magnifica, illustrative drawing. Yunxi Zhu in Yang et al. (2017)..

See also...

http://sciencythoughts.blogspot.co.uk/2017/08/coelogyne-putaoensis-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/01/habenaria-yookuaaensis-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2016/12/lecanorchis-tabugawaensis-new-species.htmlhttp://sciencythoughts.blogspot.co.uk/2016/04/epiphytic-orchids-from-lengguru-fold.html
http://sciencythoughts.blogspot.co.uk/2015/08/gastrodia-madagascariensis-not-so-new.htmlhttp://sciencythoughts.blogspot.co.uk/2015/08/catasetum-telespirense-new-species-of.html
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Asteroid 2017 VV12 passes the Earth.

Asteroid 2017 VV12 passed by the Earth at a distance of about 714 200 km (1.86 times the average distance between the Earth and the Moon,  or 0.48% of the distance between the Earth and the Sun), slightly before 3.15 pm GMT on Wednesday 15 November 2017. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2017 VV12 has an estimated equivalent diameter of 4-15 m (i.e. it is estimated that a spherical object with the same volume would be 4-15 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) in the atmosphere between 43 and 25 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2017 VV12. Minor Planet Center.

2017 VV12 was discovered on 14 November 2017 (the day before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2017 VV12 implies that it was the 321st asteroid (asteroid V12) discovered in the first half of November 2017 (period 2017 V).
 
2017 VV12 has a 767 day orbital period and an eccentric orbit tilted at an angle of 0.15° to the plane of the Solar System, which takes it from 0.97 AU from the Sun (i.e. 97% of he average distance at which the Earth orbits the Sun) to 2.31 AU from the Sun (i.e. 231% of the average distance at which the Earth orbits the Sun, more than the distance at which the planet Mars orbits). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that 2017 VV12 has occasional close encounters with the Earth, which it last came close to in February 199, and is next predicted to pass in January 2020, as well as the planet Mars, which it last came close to in April 1997.
 
See also...
 
http://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-vf14-passes-earth.htmlhttp://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-wd-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2017/11/the-leonid-meteors.htmlhttp://sciencythoughts.blogspot.co.uk/2017/11/fragments-of-metorite-found-in-british.html
http://sciencythoughts.blogspot.co.uk/2017/11/asteroid-2017-vd-passes-earth.htmlhttp://sciencythoughts.blogspot.co.uk/2017/11/asteroid-503941-2003-uv11-passes-earth.html
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Monday, 20 November 2017

Panthera leo: A gigantic Lion from the Middle Pleistocene Natodomeri deposits of the Ilemi Triangle, East Africa.

Lions, Panthera leo, first appeared in the Late Pliocene of Africa and spread across Eurasia and North America during the Pleistocene, an expansion matched only bu one other African Mammal, Homo sapiens. During this expansion some very large Lions appeared in the northern part of this range, which are sometimes considered to be separate species, Panthera spelaea, the European Cave Lion, and Panthera atrox, the American Cave Lion. However, since modern Lions are, on average, smallest at the equator and largest at the northernmost and southernmost extent of their ranges, it is possible that these large European and American Lions are simply more extreme examples of this trend from a time when the species occupied a far larger range. This is made more complicated by the fact that very few fossil Lions are known from the Pleistocene of Africa, making comparisons difficult.

In a paper published in the Journal of Paleontology on 9 November 2017, Fredrick Manthi of the Department of Earth Sciences at the National Museums of Kenya, the late Francis Brown of the Department of Geology and Geophysics at the University of Utah, Michael Plavcan of the Department of Anthropology at the University of Arkansas, and Lars Werdelin of the Department of Palaeobiology at the Swedish Museum of Natural History, describe a new and exceptionally large Lion skull from the Middle Pleistocene Natodomeri Deposits of the Ilemi Triangle.

The Ilemi Triangle is a disputed territory located between Ethiopia, South Sudan and Kenya. It is claimed by both South Sudan and Kenya, but is currently controlled and administered by Kenya. The territory has no permanent residents, but is used seasonally by a variety of pastorialist groups (nomadic Cattle herders), whose ranges also include parts of Ethiopia, South Sudan and Kenya. The Natodomeri Deposits have been worked by archaeologists and palaeontologists since the 1960s. They comprise a former northward extension of Lake Natodomeri, producing material dating from about  205 000 to about 35 000 years ago.

The new specimen is a poorly preserved partial skull, but clearly that of a Lion. In the absence of any evidence to the contrary it is assigned to the modern Lion species, Panthera leo. It is estimated to have come from a fully grown young adult, based upon analysis of dental wear. Due to its worn and damaged state it is not possible to accurately state the size of the full skull, but the teeth, generally a good proxy for this size in Leonids, are comparable in size to those of the largest Cave Lions, suggesting that this Animal, which lived close to the equator, was as large as those northern Lions.

Partial skull of Panthera leo from Natodomeri in (top) right lateral and (bottom) occlusal views. Manthi et al. (2017).

See also...

http://sciencythoughts.blogspot.co.uk/2016/12/machairodus-horribilis-new-excepionally.htmlhttp://sciencythoughts.blogspot.co.uk/2014/11/a-pantherine-big-cat-from-late-miocene.html
http://sciencythoughts.blogspot.co.uk/2014/10/a-new-species-of-leopard-cat-from-brazil.htmlhttp://sciencythoughts.blogspot.co.uk/2014/09/the-newton-abbott-lynx.html
http://sciencythoughts.blogspot.co.uk/2014/04/the-origin-and-diversification-of.html
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