The 1930 Curuçá River event refers to the possible fall of objects on 13 August 1930 over the area of Curuçá River in Brazil. It is based on the account of a single investigator who interviewed witnesses to the purported event, who then wrote a letter to the Vatican Observatory.
The event received little attention until 1995, when British astronomer Mark E. Bailey found in the Vatican Library archives a 1931 issue of L'Osservatore Romano, which contained a dispatch from the Franciscan friar Fedele d'Alviano. D'Alviano had visited the region five days after the event and interviewed people from the region; they told him they were frightened of what had happened. According to Bailey, the Curuçá event was one of the most important impact events of the 20th century.
Inspired by Bailey's article and based on images from Landsat satellites, the Brazilian astrophysicist Ramiro de la Reza attempted to find an astrobleme—the remains of a meteorite impact crater. He explored a circular feature measuring 1 km in diameter, to the southeast of the village of Argemiro, but found no evidence for impact.
In the first week of June 1997, de la Reza led an expedition organized by Rede Globo and co-financed by ABC Television of Australia, to the region where the event is said to have occurred. Subsequent researchers have concluded that the circular feature is unrelated to the reported event, and is not an impact crater.
Assuming that the reported event was an air burst, various researchers have estimated the initial mass of the meteor at between 1,000 and 25,000 tons. Estimates for the energy released have varied from 9 kilotons, 100 kilotons, and 5 megatons, though most estimates place the energy at below 1 megaton.
Events in the year 1930 in Brazil.2018 LA
2018 LA, also known as ZLAF9B2, was a small Apollo near-Earth asteroid approximately 2.6–3.8 m (9–12 ft) in diameter that impacted Earth at roughly 16:44 UTC (18:44 local time) on 2 June 2018 near the border of Botswana and South Africa. It was discovered only 8 hours prior by the Mount Lemmon Survey, and based on an hour and a half of observations, it was calculated to have a roughly 85% chance of impacting Earth, likely somewhere between Australia and Madagascar. Hours later, a report arrived to the American Meteor Society that an observer from Botswana had seen a bright fireball. After the impact, the Asteroid Terrestrial-impact Last Alert System (ATLAS) released observations roughly 2 hours after the other reported observations which confirmed that the asteroid had indeed impacted Earth on a grazing path and near the location of the fireball. A preliminary analysis of the pre-impact evolution of this meteoroid suggests that it may be part of a dynamical grouping.Air burst
An air burst or airburst is the detonation of an explosive device such as an anti-personnel artillery shell or a nuclear weapon in the air instead of on contact with the ground or target or a delayed armor-piercing explosion. The principal military advantage of an air burst over a ground burst is that the energy from the explosion (as well as any shell fragments) is distributed more evenly over a wider area; however, the peak energy is lower at ground zero.
The term may also refer to naturally occurring air bursts arising from the explosions of incoming meteors as happened in the Tunguska event, the 1930 Curuçá River event, and the Chelyabinsk meteor event.Amazon River
The Amazon River (US: , UK: ; Spanish and Portuguese: Amazonas) in South America is the largest river by discharge volume of water in the world, and by some definitions it is the longest.The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon's most distant source, until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru. The Mantaro and Apurímac join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters (Portuguese: Encontro das Águas) at Manaus, the river's largest city.
At an average discharge of about 209,000 cubic metres per second (7,400,000 cu ft/s; 209,000,000 L/s; 55,000,000 USgal/s)—approximately 6,591 cubic kilometres per annum (1,581 cu mi/a), greater than the next seven largest independent rivers combined—the Amazon represents 20% of the global riverine discharge to the ocean. The Amazon basin is the largest drainage basin in the world, with an area of approximately 7,050,000 square kilometres (2,720,000 sq mi). The portion of the river's drainage basin in Brazil alone is larger than any other river's basin. The Amazon enters Brazil with only one-fifth of the flow it finally discharges into the Atlantic Ocean, yet already has a greater flow at this point than the discharge of any other river.Chelyabinsk meteor
The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over Russia on 15 February 2013 at about 09:20 YEKT (03:20 UTC). It was caused by an approximately 20 m (66 ft) near-Earth asteroid with a speed of 19.16 ± 0.15 kilometres per second (60,000–69,000 km/h or 40,000–42,900 mph). It quickly became a brilliant superbolide meteor over the southern Ural region. The light from the meteor was brighter than the Sun, visible up to 100 km (62 mi) away. It was observed over a wide area of the region and in neighbouring republics. Some eyewitnesses also felt intense heat from the fireball.
Due to its high velocity and shallow angle of atmospheric entry, the object exploded in an air burst over Chelyabinsk Oblast, at a height of around 29.7 km (18.5 mi; 97,000 ft). The explosion generated a bright flash, producing a hot cloud of dust and gas that penetrated to 26.2 km (16.3 mi), and many surviving small fragmentary meteorites, as well as a large shock wave. The bulk of the object's energy was absorbed by the atmosphere, with a total kinetic energy before atmospheric impact estimated from infrasound and seismic measurements to be equivalent to the blast yield of 400–500 kilotons of TNT (about 1.4–1.8 PJ) range – 26 to 33 times as much energy as that released from the atomic bomb detonated at Hiroshima.The object was undetected before its atmospheric entry, in part because its radiant was close to the Sun. Its explosion created panic among local residents, and about 1,500 people were injured seriously enough to seek medical treatment. All of the injuries were due to indirect effects rather than the meteor itself, mainly from broken glass from windows that were blown in when the shock wave arrived, minutes after the superbolide's flash. Some 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures.
With an estimated initial mass of about 12,000–13,000 metric tons (13,000–14,000 short tons, heavier than the Eiffel Tower), and measuring about 20 m (66 ft) in diameter, it is the largest known natural object to have entered Earth's atmosphere since the 1908 Tunguska event, which destroyed a wide, remote, forested, and very sparsely populated area of Siberia. The Chelyabinsk meteor is also the only meteor confirmed to have resulted in a large number of injuries. No deaths were reported.
The earlier-predicted and well-publicized close approach of a larger asteroid on the same day, the roughly 30 m (98 ft) 367943 Duende, occurred about 16 hours later; the very different orbits of the two objects showed they were unrelated to each other.Curuçá River (Javari River)
Curuçá River is a river of Amazonas state in northwestern Brazil. It is entirely within the municipality of Atalaia do Norte.List of meteor air bursts
Many explosions recorded in Earth's atmosphere are likely caused by the air burst that results from a meteor exploding as it hits the thicker part of the atmosphere. These types of meteors are also known as fireballs or bolides with the brightest known as superbolides. Before entering Earth's atmosphere, these larger meteors were originally asteroids and comets of a few to several tens of meters in diameter, contrasting with the much smaller and much more common "shooting stars".
The most powerful recorded air burst is the 1908 Tunguska event. Extremely bright fireballs traveling across the sky are often witnessed from a distance, such as the 1947 Sikhote-Alin meteor and the 2013 Chelyabinsk meteor, both in Russia. If the bolide is large enough, fragments may survive such as the Chelyabinsk meteorite. Modern developments in infrasound detection by the Comprehensive Nuclear-Test-Ban Treaty Organization and infrared Defense Support Program satellite technology have increased the likelihood of detecting airbursts.Timeline of Brazilian history
This is a timeline of Brazilian history, comprising important legal and territorial changes and political events in Brazil and its predecessor states. To read about the background to these events, see History of Brazil.Tunguska event
The Tunguska event was a large explosion that occurred near the Stony Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908 (NS). The explosion over the sparsely populated Eastern Siberian Taiga flattened 2,000 square kilometres (770 square miles) of forest, yet caused no known human casualties. The explosion is generally attributed to the air burst of a meteor. It is classified as an impact event, even though no impact crater has been found; the object is thought to have disintegrated at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than to have hit the surface of the Earth.The Tunguska event is the largest impact event on Earth in recorded history. Studies have yielded different estimates of the meteoroid's size, on the order of 60 to 190 metres (200 to 620 feet), depending on whether the body was a comet or a denser asteroid.Since the 1908 event, there have been an estimated 1,000 scholarly papers (most in Russian) published on the Tunguska explosion. In 2013, a team of researchers published analysis results of micro-samples from a peat bog near the center of the affected area showing fragments that may be of meteoritic origin.Early estimates of the energy of the air burst range from 10–15 megatons of TNT (42–63 petajoules) to 30 megatons of TNT (130 PJ), depending on the exact height of burst estimated when the scaling-laws from the effects of nuclear weapons are employed. However, modern supercomputer calculations that include the effect of the object's momentum find that more of the energy was focused downward than would be the case from a nuclear explosion and estimate that the airburst had an energy range from 3 to 5 megatons of TNT (13 to 21 PJ).The 15-megaton (Mt) estimate represents an energy about 1,000 times greater than that of the atomic bomb dropped on Hiroshima, Japan—roughly equal to that of the United States' Castle Bravo (15.2 Mt) ground-based thermonuclear detonation on 1 March 1954, and about one-third that of the Soviet Union's Tsar Bomba explosion on 30 October 1961 (which, at 50 Mt, is the largest nuclear weapon ever detonated).It is estimated that the Tunguska explosion knocked down some 80 million trees over an area of 2,150 km2 (830 sq mi), and that the shock wave from the blast would have measured 5.0 on the Richter magnitude scale. An explosion of this magnitude would be capable of destroying a large metropolitan area, but, due to the remoteness of the location, no human fatalities were officially documented. Several reports have indicated that two people may have died in the event, but those deaths remain unofficial. The Tunguska event has helped to spark discussion of asteroid impact avoidance.