Sunday 31 March 2019

Kashmir farmer injured by Leopard.

A farmer from Budgam District in Jammu and Kashmir, India, is being treated in Chadoora Hospital after being attacked by a Leopard on Sunday 31 March 2019. Shameem Ahmad Bhat, from Madbal Village was attacked by a female Leopard shortly after finding two cubs, which he initially assumed to be domestic Cats. The cubs were later captured by Wildlife Department officers, who report they were both severely undernourished, and steps attempts are still being made to capture the mother. It is possible that the animals had come onto the farmers property searching for food.

A female Leopard in the Dachigam Wildlife Sanctuary near Srinagar in Jammu and Kashmir in 2014. Deccan Chronicle.

Leopards are considered to be Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, with the Indian subspecies, Panthera pardus fusca, considered to be particularly vulnerable due to India's rapidly rising Human population, which has resulted in agriculture and other Human activities expanding into many former wilderness areas. For this reason the Indian Forest Service usually try to relocate Leopards that come into conflict with Humans to more remote areas, preferably within national parks, though the extent to which local people co-operate is variable.

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Asteroid 2019 FC1 passes the Earth.

Asteroid 2019 FC1 passed by the Earth at a distance of about 103 200 km (0.27 times the average distance between the Earth and the Moon, or 0.07% of the distance between the Earth and the Sun), slightly after 5.45 am GMT on Thursday 28 March 2019. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2019 FC1 has an estimated equivalent diameter of 14-45 m (i.e. it is estimated that a spherical object with the same volume would be 14-45 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 28 and 10 km above the ground, with only fragmentary material reaching the Earth's surface.

 The calculated orbit of 2019 FC1. JPL Small Body Database.

2019 FC1 was discovered on 29 March 2019 (the day after 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 2019 FC1 implies that the asteroid was the 27th object (object C1 - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 24, so that M5 = (24 x 1) + 3 = 27) discovered in the second half of March 2019 (period 2019 F).

2019 FC1 has an 1202 day orbital period and an eccentric orbit tilted at an angle of 1.98° to the plane of the Solar System, which takes it from 0.43 AU from the Sun (i.e. 43% of the the average distance at which the Earth orbits the Sun, and slightly outside the orbit of Mercury) to 3.99 AU from the Sun (i.e. 399% of the average distance at which the Earth orbits the Sun, and somewhat more than twice the distance at which 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 close encounters between the asteroid and Earth are common, with the last having occurred in October 1981  and the next predicted in October 2071.

2019 FC1 also has frequent close encounters with the planets Venus, which it last came close to in November 1984 and is next predicted to pass in December 2071, Mars, which it last passed in October 1984 and Jupiter, which it last came close to in October 1983 and is next predicted to pass in January 2067. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.

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Gujarat man wakes to find Crocodile under his bed.

A farmer in Anand District, Gujarat, had a nasty surprise this week when he woke to find a two-and-a-half metre Mugger Crocodile, Crocodylus palustris, lurking under his bed. Babubhai Parmar, 30, discovered the animal in his home in Malataj Village, at about 1.30 am local time on Monday 25 March 2018, when he was woken by barking Dogs. Usually villagers in the area would have felt confident to remove the Crocodile himself, but realising it was likely to be a gravid female (Mugger Crocodiles typically begin to lay their eggs in April in India, and start to look for suitable nesting sites some weeks before this), they called for help and the animal was eventually removed by Forest Department officials.

 A Mugger Crocodile, Crocodylus palustris, beneath a bed in Malataj Village, Gujarat, this week. Times of India.

Mugger Crocodiles were formerly found across South Asia from Iran to Myanmar and Nepal to Sri Lanka, but they are thought to be extinct in Myanmar, Bhutan, and Bangladesh, and is considered to be Vulnerable under the terms of the International Union for the Conservation of Nature’s Red List of  Threatened Species. Muggers are smaller that Saltwater and Nile Crocodiles, with males reaching about 3.5 m and females about 2.5 m, and are generally less considered less dangerous, as their preferred prey is animals smaller than Humans. However, as with other Crocodylians, the females can be highly aggressive during the nesting season (April to June), and people are occasionally killed by these animals.

The village of Malataj lies on a lake of the same name which is home to a population of about 140 Muggers, with the villagers and the Crocodiles typically co-existing peacefully, with some villagers even tolerating Crocodiles nesting in their gardens. Despite this local tolerance, conservationists in the area have warned that the Crocodiles are currently at risk due to a number of Human activities, from increasingly busy roads to increasing use of pesticides. 

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Magnitude 6.2 Earthquake off the coast of Santa Elena, Ecuador.

The United States Geological Survey recorded a Magnitude 6.2 Earthquake at a depth of 18.5 km, roughly 27 km off the coast of Santa Elana Province, Ecuador, slightly before 2.05 am local time (slightly before 7.05 am GMT) on Sunday 31 March 2019. There are no reports of any damage or casualties associated with this event, but the event was felt across much of western Ecuador.

The approximate location of the 31 March 2019 Santa Elena Earthquake. USGS.

Ecuador is on the west coast of South America and the western margin of the South American Plate, close to where the Nazca Plate, which underlies part of the east Pacific, is being subducted along the Peru-Chile Trench. The Nazca Plate passes under the South American Plate as it sinks into the Earth, this is not a smooth process and the plates repeatedly stick together then break apart as the pressure builds up, causing Earthquakes. As the Nazca Plate sinks further it is melted by the heat of the Earth's interior. Some of this melted material then rises through the overlying South American Plate, fuelling the volcanoes of Ecuador and neighbouring countries.

The subduction of the Nazca Plate beneath the South American Plate, and how it causes Earthquakes and volcanoes. SIO SEARCH.

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.

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Fireball meteor over New York State.

The American Meteor Society has received reports of a bright fireball meteor being seen over the eastern New York State, slightly before 6.15 am Eastern Standard Time (slightly before 10.15 am GMT) on Thursday 28 March 2019. The meteor was also seen from Connecticut, Delaware, Maryland, Pennsylvania, Vermont, New Jersey, Virginia, Maine, Rhode Island, New Hampshire, Florida, Massachusetts, West Virginia, and Washington DC, though the majority of the reports came from New York. 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. 

Stack image (image made up of several different photographs) of the 28 March 2019 New York meteor, taken from Douglassville, Pennsylvania. Peter Deterline/American Meteor Society.

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. This object appeared to move southeast-to-northwest, disappearing to the northwest of Pine Hill in Ulster County, New York.

 Map showing areas where sightings of the meteor were reported, and the apparent path of the object (blue arrow). 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).
Estimated 3D trajectory of the 28 March 2019 New York Meteor. 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
Witness reports can help astronomers to understand these events. If you witness a fireball-type meteor over the US you can report it to the American Meteor Society here.   
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Possible second large impact crater beneath the Greenland Ice Sheet.

The discovery of large impact craters is now a rare event in even the most remote locations on Earth, and it is highly unlikely that any such structures larger than about 6 km in diameter are left to be discovered exposed on the Earth's surface. However such structures are not always exposed at the surface, and large impact craters are still sometimes discovered beneath desert sands, shallow seas or polar ice sheets. One such discovery was announced in a paper published in the journal Science Advances on 14 November 2018, by a team of scientists led by Kurt Kjær of the Centre for GeoGenetics at the Natural History Museum of Denmark at the University of Copenhagen, who described a 31 km diameter impact crater beneath the Hiawatha Glacier in northwest Greenland.

In a paper published in the journal Geophysical Research Letters on 11 February 2019, Joseph MacGregor of the Cryospheric Sciences Laboratory at NASA's Goddard Space Flight Center, William Bottke of the Department of Space Studies at the Southwest Research Institute, Mark Fahnestock of the Geophysical Institute at the University of Alaska Fairbanks, Jeremy Harbeck, also of the Cryospheric Sciences Laboratory at NASA's Goddard Space Flight Center, and of ADNET Systems, Inc., Kurt Kjær of the Centre for GeoGenetics at the Natural History Museum of Denmark at the University of Copenhagen, John Paden of the Center for Remote Sensing of Ice Sheets at the University of Kansas, and Michael Studinger, again of the Cryospheric Sciences Laboratory at NASA's Goddard Space Flight Center, describe a possible second large impact crater beneath the Greenland Ice Sheet.

MacGregor et al. examined commercial satellite data from the ArcticDEM Polar Geospatial Center, as well as aerogeophysical surveys and satellite data produced by NASA over the past 25 years. Using this data they identify a structure roughly 183 to the southeast of the Hiawatha Crater, which they provisionally name the Peterson Crater, in honour of the eminent Scottish glaciologist Stan Paterson, who helped to survey the area during the 1953–1954 British North Greenland Expedition. The structure is approximately 36.5 km in diameter and is covered by up to 2180 m of ice. It has a maximum depth of 160 m, from the highest point on the rim to the lowest point in its basin, with an inner ring of peaks 23 km in diameter (inner rings of peaks are common in larger impact structures).

(a) Hillshaded ArcticDEM surface elevation across northwestern Greenland, showing both the Hiawatha impact crater along the ice margin and the presently identified structure farther inland to the southeast. Horizontal lines across the panel are mosaicking artifacts. Magenta arrows indicate location of both structures. Locations of 1953–1954 British North Greenland Expedition (BNGE) traverse stations, 1959–1967 Camp Century station, and 1995 Humboldt Glacier shallow ice core sites. (b) Map of Greenland with black box showing location of panels (a) and (c). (c) Gridded subglacial topography across northwestern Greenland. MacGregor et al. (2019).

Based upon ice cores measurements in the region, which enable the dating of reflective surfaces within the ice, MacGregor et al. conclude that the Paterson Crater is at least 79 000 years old. They also note that, given the crater's size, it must have had an original depth in excess of 1km, and that for this to have eroded down to the current profile would have taken at least 100 000 years. This in turn suggests that the structure is somewhat older than the Hiawatha Crater, which has a minimum age of about 11 700 years (though it is probably older than this), and which is much less eroded, ruling out the possibility of the two craters having originated from a double impact (where a single large object broke up as it entered the atmosphere and hit the ground in two pieces).

Finding two large impact craters within 183 km with separate origins at first seems somewhat unlikely, indeed MacGregor et al. calculate that the odds against  a crater-forming object hitting the ground within 183 km of any given point within 1.5 million years is 2.1 in 10 000. However, whilst this seems somewhat unlikely, MacGregor et al. also calculate that given a random distribution of impacts on Earth, and the amount of available stable terrain in which craters can be preserved, the Earth's surface should contain 1-2 craters of this size that lie within 183 km of one another by random chance, making the discovery significant, but less statistically implausible.

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Saturday 30 March 2019

Flash floods kill at least 39 in northern Afghanistan.

At least 39 people have died and thousands more have been made homeless in flash flooding following heavy rain across northern Afghanistan this week. A total of twelve people have been confirmed dead in the province of Jawzjan, with ten confirmed dead in Herat, eight in Faryab, eight in Badghis, and one in Sar-e Pul, with the number of unrecorded casualties likely to be larger in all these provinces. 

Flooding in the Enjil District of Herat Province this week. Jalil Ahmad/Reuters.

Flash floods and landslides are a frequent problem in northern Afghanistan, where a mostly dry climate is broken by occasional bouts of heavy rainfall. The dry nature of the climate means that little of the landscape is covered by extensive vegetation (which can stabilise hillsides with root-growth), making the area vulnerable to flash floods. This situation is made worse by the widespread use of dried mud bricks as a building material, resulting in buildings that offer little protection against flooding and are easily swept away. 

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