Sciency Thoughts

Sunday, 10 April 2022

Asteroid 2022 GN1 passes the Earth.

Asteroid 2022 GN1 passed by the Earth at velocity of 15.51 km per second and a distance of about 125 600 km (0.33 times the average distance between the Earth and the Moon, or 0.08% of the distance between the Earth and the Sun, about 308 times the distance at which the International Space Station obits, and 35 times as far from the Earth than satellites in geostationary orbits), slightly after 3.00 am GMT on Wednesday 6 March 2022. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2022 GN1 has an estimated equivalent diameter of 5-17 m (i.e. it is estimated that a spherical object with the same volume would be 5-17 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 25 km above the ground, with only fragmentary material reaching the Earth's surface.

120 second image of 2022 GN2 taken with the Elena Planetwave 17" Telescope at Ceccano in Italy on 5 April 2020. 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. Gianluca Masi/Virtual Telescope Project.

2022 GN1 was discovered on 4 April 2022 (two days 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 2022 GN1 implies that the asteroid was the 38th object (asteroid N1 - 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 = 26, A2 = 51, etc., which means that N1 = 25 + 13 = 38) discovered in the first half of April 2022 (period 2022 G - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The relative positions of 2022 GN1 and the Earth on at 3.00 am on 6 March 2022. JPL Small Body Database.

2022 GN1 is calculated to have a 947 day (2.59 year) orbital period, with an elliptical orbit tilted at an angle of 2.70° to the plain of the Solar System which takes in to 0.78 AU from the Sun (78% of the distance at which the Earth orbits the Sun) and out to 3.00 AU (three times the distance at which the Earth orbits the Sun, or roughly twice 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 2022 GN1 has occasional close encounters with the Earth, with the last thought to have happened in September 1957 and the next predicted in September 2030.

The orbit and current position of 2022 GN1. The Sky Live 3D Solar System Simulator.

Canadian Salmon farm invaded by Sea Lions.

A Salmon farm on the coast of British Columbia has been invaded by a group of Sea Lions, raising alarm among conservation groups, who fear they may become habituated to the environment. The Rant Point Salmon Farm near Tofino was the subject of an 'invasion event' in mid-March, according to Cermaq, the Norwegian multinational that runs the site, along with several others on the coast of British Columbia, and at other sites in Norway and Chile. However, conservation groups were not informed of the event until Sunday 3 April, when a Whale-watching trip observed the Sea Lions moving in and out of pens.

A Sea Lion consuming a Salmon at the Rant Point Salmon Farm in British Columbia. Jérémy Mathieu/Clayoquot Action.

Several previous Sea Lion invasions have been recorded at Salmon Farms in British Columbia, resulting in heavy losses of Fish stocks (Sea Lions can consume up to three times their own bodymass in Fish each day, piling on fat which enables them to survive seasonal food shortages), and numerous Sea Lion deaths through entanglement. During a previous invasion at Rant Point in 2016, the Canadian Department of Fisheries allowed the company to shoot the offending Sea Lions, but this stance has not been repeated in 2022, with the same body insisting that only methods which remove the Animals without hurting them can be used. This is part of a wider change in policy on Salmon farming in Canada, which now wants to see the practice phased out by 2025, following years of campaigning by conservation and indigenous rights groups.

Sea Lions inside and outside Salmon Pens at the Rant Point Salmon Farm in British Columbia. Jérémy Mathieu/Clayoquot Action.

Salmon farming on the coast of British Columbia brings employment to the area, and enables farmers to access lucrative US markets easily, but, as in other areas where it is practiced, is strongly opposed by environmental groups. Farmed Salmon, which live at far higher densities than would naturally be the case, are seen as a reserve for Salmon diseases, which can go on to infect wild Salmon, with potentially devastating effects on wild populations. This has potential knock-on effects for many other species, including marine predators such as Sea Lions which rely upon them for food, but also Bears and even forest trees far from the shore. This is due to the complex life cycle of the Salmon, which spend much of their lives at sea, acquiring nutrients from marine sources, before swimming back up the rivers where they were born to mate, spawn, and die. Since most natural processes tend to wash nutrients downstream from the land to the sea, this makes Salmon important ecosystem engineers in British Colombia and other areas of natural temperate rainforests.

Salmon farms are also seen as highly poluting. This is because Salmon are predatory Fish, requiring farmed Salmon to be fed with Fish meal (generally made from wild-caught Fish species not favoured as food by Humans, raising further concerns about links between Salmon farming and overfishing), with the effect that both waste food and Salmon droppings are potential environment-changing pollutants. Furthermore, the problem of infections spreading easily within Salmon farms often results in farmers dosing the water with antibiotics and other medications, causing further environmental problems, and potentially leading to the spread of anti-biotic resistance in marine pathogens.

Saturday, 9 April 2022

Petalacmis triplehorni: A new species of Firefly from Bolivia.

Fireflies, Lampyridae, are Beetles closely related to Soldier and Click Beetles, noted for their remarkable light producing organs. These appear to have first developed in the larvae, which use them to warn potential predators of their unpleasant taste, but have been retained into adulthood in males of some species and co-opted for mating displays, with the females of one species also retaining these organs, and using them to attract members of other species, which are preyed on. The conspicuous nature of these Insects means that they have been observed since antiquity, with many cultures attributing supernatural significance to their appearance. However, they are relatively understudied from South America, with only two species described from South America, both placed within the genus Petalacmis, with only the males known from either species.

In a paper published in the journal ZooKeys on 4 April 2022, Luiz Lima da Silveira of the Department of Biology at Western Carolina University, and Marc Branham of the Department of Entomology and Nematology at the University of Florida, describe a new species of Petalacmis from the Santa Cruz Department of Bolivia.

The new species is named Petalacmis triplehorni, in honour of Charles 'Chuck' Triplehorn, Professor Emeritus of the Ohio State University, who collected the first specimens of Petalacmis praeclarus that Marc Branham first encountered as a graduate student while investigating the systematics of the family Lampyridae, and served as a mentor and an inspiration to him. The species is described from fifteen specimens, collected from different locations within Santa Cruz Department by different collectors between 2000 and 2005.

Petalacmis triplehorni, holotype (male, prior to dissection), habitus (A) dorsal (B) ventral. Scale bar is 1 mm. Da Silveira & Branham (2022).

Known male specimens of Petalacmis triplehorni are dark brown in colour, and vary between 5.06 and 5.81 mm in length. Their antennae are distinctive, with only nine antennomeres (antennal segments), the ninth of which is very elongate and paddle-shaped. The elytra (wing cases) are subparallel, the abdomen approximately diamond shaped.