Observed Fall Research Articles

Россия в сверхкритической ситуации: управление восстановлением функций жизнеобеспечения для преодоления последствий природной макрокатастрофы

Supercritical fluid is a state of matter when its temperature and pressure are above the critical point. Supercritical situation is a state of the economy in its cumulative manifestations and mutual influence, whereby the state of key life-support profiles is below the critical point of controllability. Various forecasts are increasingly actualizing the probability of a natural (and man-made) macro-catastrophe (a large meteorite fall, an earthquake of 10–12 points and others, as well as a pandemic similar to COVID–19, but with more severe consequences). As the coronavirus pandemic has shown, modern civilization is becoming ever more vulnerable to such disasters. To overcome the destabilizing trends of a natural (and man-made) macro-catastrophe, it is necessary to adopt proactively a set of measures in Russia that will drastically increase the efficiency of public administration in relation to the list of regulated resource, economic, technical, social and other parameters incorporating mechanisms and procedures of public administration into market mechanisms and the budgeting structure with regard to external and internal factors of the supersystem's vital activities.

Bolide fragment detection in Doppler weather radar data using artificial intelligence/machine learning

AbstractUnsupervised machine learning methods present a promising approach for detecting fragments produced from meteors and bolides as distinct signatures within Doppler weather radar data. A method combining principal component analysis (PCA), t‐distributed statistical neighbor embedding (t‐SNE), and data point pruning based on the nearest neighbor algorithm is introduced as a process to detect outlier meteor signatures from terrestrial weather signatures using the national NOAA WSR‐88D Doppler radar network. This method is applied against unlabeled data from four weather radar sites during two bolide events: the KFWS radar for the Ash Creek bolide and the KDAX, KRGX, and KBBX radars for the Sutter’s Mill bolide. The combined algorithm results in an accuracy rate of 99.7% and can classify the data in <8 min for a 121,000 return sized data set. However, the classifier’s recall and precision rates remained low due to difficulties in correctly classifying true‐positive meteorite fall events. This method enables the expedited detection of materials from bolides and meteors that fall within the national radar network, leading to the faster confirmation of meteorite fall events and subsequent dispatch of recovery teams.

Genesis and Geoecological Changes of the South Caspian Depression after a Meteorite Fall

Genesis and Geoecological Changes of the South Caspian Depression after a Meteorite Fall

Recovery of meteorites using an autonomous drone and machine learning

AbstractThe recovery of freshly fallen meteorites from tracked and triangulated meteors is critical to determining their source asteroid families. Even though our ability to locate meteorite falls continues to improve, the recovery of meteorites remains a challenge due to large search areas with terrain and vegetation obscuration. To improve the efficiency of meteorite recovery, we have tested the hypothesis that meteorites can be located using machine learning techniques and an autonomous drone. To locate meteorites autonomously, a quadcopter drone first conducts a grid survey acquiring top‐down images of the strewn field from a low altitude. The drone‐acquired images are then analyzed using a machine learning classifier to identify meteorite candidates for follow‐up examination. Here, we describe a proof‐of‐concept meteorite classifier that deploys off‐line a combination of different convolution neural networks to recognize meteorites from images taken by drones in the field. The system was implemented in a conceptual drone setup and tested in the suspected strewn field of a recent meteorite fall near Walker Lake, Nevada.

To be or not to be, that is the question: The Marsala meteorite (Italy, 1834) and the role of the doubtful meteorites in the history of meteoritics

AbstractThis work focuses on the historical and scientific investigation of a presumed meteorite fall that occurred in the Sicilian township of Marsala in 1834. Preliminary studies have classified this phenomenon as a “doubtful meteorite.” This term describes, according to the Nomenclature Committee of the Meteoritical Society, an object for which there was significant uncertainty over whether it was a real meteorite or, in some cases, whether it ever existed. Thanks to the analysis of untapped sources, the first objective of this work is to clarify the nature of the event. Subsequently, the results of the minero‐chemical analyses that were performed, in 1835, on two fragments recovered after the event are discussed for the first time. This work then shows the collecting history of one of the presumed meteorite specimens. Based on the results presented here, this work highlights the role of doubtful meteorites as a fundamental resource for the history of meteoritics and meteorite collecting as well as for studying the processes that have led to the scientific study of meteorites.

An investigation of the 27 July 2018 bolide and meteorite fall over Benenitra, southwestern Madagascar

Several dozen stones of an ordinary chondrite meteorite fell in and around the town of Benenitra in southwestern Madagascar during the early evening of 27 July 2018, minutes after a widely observed meteor fireball (bolide) transit and detonation. The event was confirmed by low-frequency infrasound recordings received at ~17h15 UTC (Coordinated Universal Time; 19h15 local time) at the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) infrasound station I33MG near Antananarivo, 542 km north-northeast of Benenitra. An energy release equivalent to 2.038 kt of TNT was calculated from the infrasound signals. Seismograph readings at the SKRH station 77 km north-northwest of Benenitra recorded a twostage signal consistent with the arrivals of an initial air-coupled ground wave at 16h48:08 UTC and a stronger pulse at 16h49:22 UTC linked directly to the atmospheric pressure wave. The infrasound and seismic signal arrival times suggest that the bolide entry and detonation occurred at approximately 18h46 local time (16h46 UTC), entry was from the northwest, and the detonation hypocentre was located within ~20 km of Benenitra. Despite meteorite debris being found among buildings within Benenitra, there was no damage to structures or injuries reported. Eyewitness accounts and photographic records indicate that approximately 75 mostly intact stones were collected; however, the remoteness of the area, the rugged nature of the terrain and sales of fragments to meteorite collectors have limited scientific analysis of the fall and the extent of the strewn field. The total mass of recovered stones is estimated at between 20 kg and 30 kg, with one fragment of 11.2 kg and several of ~1 kg. Petrographic and mineral chemical analyses indicate that the stones belong to the L6 class of ordinary chondrites. Cosmogenic radionuclide analysis confirms that the fall is linked to the bolide event. The name Benenitra has been officially accepted by the Meteoritical Bulletin Database.Significance:
 
 Eyewitness reports, CTBTO infrasound records, seismograph records and cosmogenic radionuclide analysis confirm a meteorite fall over Benenitra on 27 July 2018.
 Petrographic and geochemical analyses confirm that the meteorite is an L6 ordinary chondrite.
 Recovery of meteorite falls is rare; this is Madagascar’s second known meteorite fall and the first that can be linked to a bolide.
 Regional and global science monitoring networks can be interrogated to improve the understanding of bolide events.
 Interaction of scientists with local communities is important to dispel misunderstandings around scientific phenomena, and can improve collection of data.

Determination of strewn fields for meteorite falls

ABSTRACTWhen an object enters the atmosphere it may be detected as a meteor. A bright meteor, called a fireball, may be a sign of a meteorite fall. Instrumentally observed meteorite falls provide unique opportunities to recover and analyse unweathered planetary samples supplemented with the knowledge on the Solar system orbit they had. To recover a meteorite from a fireball event, it is essential that recovery teams can be directed to a well-defined search area. Until recently, simulations showing the realistic mapping of a strewn field were difficult, in particular due to the large number of unknowns not directly retrieved from the fireball observations. These unknowns include the number of fragments and their aerodynamic properties, for which the masses of the fragments need to be assumed in a traditional approach. Here, we describe a new Monte Carlo model, which has already successfully assisted in several meteorite recoveries. The model is the first of its kind as it provides an adequate representation of the processes occurring during the luminous trajectory coupled together with the dark flight. In particular, the model comprises a novel approach to fragmentation modelling that leads to a realistic fragment mass distribution on the ground. We present strewn field simulations for the well-documented Košice and Neuschwanstein meteorite falls, which demonstrate good matches to the observations. We foresee that our model can be used to revise the flux of extra-terrestrial matter onto the Earth, as it provides a possibility of estimating the terminal mass of meteorite fragments reaching the ground.

Mineralogy, petrology, geochemistry, and chronology of the Murrili (H5) meteorite fall: The third recovered fall from the Desert Fireball Network

AbstractMurrili, the third meteorite recovered by the Desert Fireball Network, is analyzed using mineralogy, oxygen isotopes, bulk chemistry, physical properties, noble gases, and cosmogenic radionuclides. The modal mineralogy, bulk chemistry, magnetic susceptibility, physical properties, and oxygen isotopes of Murrili point to it being an H5 ordinary chondrite. It is heterogeneously shocked (S2–S5), depending on the method used to determine it, although Murrili is not obviously brecciated in texture. Cosmogenic radionuclides yield a cosmic ray exposure age of 6–8 Ma, and a pre‐atmospheric meteoroid size of 15–20 cm in radius. Murrili’s fall and subsequent month‐long embedment into the salt lake Kati Thanda significantly altered the whole rock, evident in its Mössbauer spectra, and visual inspection of cut sections. Murrili may have experienced minor, but subsequent, impacts after its formation 4475.3 ± 2.3 Ma, which left it heterogeneously shocked.

The polymict carbonaceous breccia Aguas Zarcas: A potential analog to samples being returned by the OSIRIS‐REx and Hayabusa2 missions

AbstractOn April 23, 2019, a meteorite fall occurred in Aguas Zarcas, Costa Rica. According to the Meteoritical Bulletin, Aguas Zarcas is a brecciated CM2 chondrite dominated by two lithologies. Our X‐ray computed tomography (XCT) results show many different lithologies. In this paper, we describe the petrographic and mineralogical investigation of five different lithologies of the Aguas Zarcas meteorite. The bulk oxygen isotope compositions of some lithologies were also measured. The Aguas Zarcas meteorite is a breccia at all scales. From two small fragments, we have noted five main lithologies, including (1) Met‐1: a metal‐rich lithology; (2) Met‐2: a second metal‐rich lithology which is distinct from Met‐1; (3) a brecciated CM lithology with clasts of different petrologic subtypes; (4) a C1/2 lithology; and (5) a C1 lithology. The Met‐1 lithology is a new and unique carbonaceous chondrite which bears similarities to CR and CM chondrite groups, but is distinct from both based on oxygen isotope data. Met‐2 also represents a new type of carbonaceous chondrite, but it is more similar to the CM chondrite group, albeit with a very high abundance of metal. We have noted some similarities between the Met‐1 and Met‐2 lithologies and will explore possible genetic relationships. We have also identified a brecciated CM lithology with two primary components: a chondrule‐poor lithology and a chondrule‐rich lithology showing different petrologic subtypes. The other two lithologies, C1 and C1/2, are very altered and possibly related to the CM chondrite group. In this article, we describe all the lithologies in detail and attempt a classification of each in order to understand the origin and the history of formation of the Aguas Zarcas parent body.

FRIPON: a worldwide network to track incoming meteoroids

Context.Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile – hence precious – meteorites must be recovered rapidly to avoid their alteration.Aims.The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receivers and covers an area of about 1.5 × 106km2.Methods.The FRIPON network, fully operational since 2018, has been monitoring meteoroid entries since 2016, thereby allowing the characterization of their dynamical and physical properties. In addition, the level of automation of the network makes it possible to trigger a meteorite recovery campaign only a few hours after it reaches the surface of the Earth. Recovery campaigns are only organized for meteorites with final masses estimated of at least 500 g, which is about one event per year in France. No recovery campaign is organized in the case of smaller final masses on the order of 50 to 100 g, which happens about three times a year; instead, the information is delivered to the local media so that it can reach the inhabitants living in the vicinity of the fall.Results.Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag < –5; meteoroid size ≥~1 cm) amounts to 1250/yr/106km2. This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020) thanks to the PRISMA network, a component of the FRIPON science project.

ALTERNATIVE SOURCES OF ENERGY IN GREEN TOURISM

The article considers promising areas of green tourism development in Vinnytsia region. Describes a number of extremely unique and interesting objects that are little known to tourists. These include the «Illinets astroblem» ˗ craters at the site of a meteorite fall 400 million years ago. The crater is located between the villages of Ivanky, Lypovets district and Luhovo, Illinets district. They arose as a result of the fall to Earth of a cosmic body with an approximate weight of 40 million tons. The diameter of the meteorite is about 230 - 300 m. At the time of the fall, the meteorite was divided into 3 parts. As a result, 13 craters appeared. The largest of them have diameters of 7-10 km. According to experts, the initial depth of the largest crater was about 800 m. The local places are witnesses of a unique phenomenon of planetary scale and are interesting for the tourist business. There are no analogues to Ilyinets Crater in the world. The problems of exhaustion of traditional energy sources are analyzed, and in this connection the inevitable increase in their price. The necessity of wide introduction of alternative energy in the field of green rural tourism is proved. The use of autonomous, network and hybrid solar semiconductor power plants is. promising. Grid-connected solar power plants as an object of solar energy can be used both to generate electricity for household consumption and for the purpose of further sale to the national grid at a green tariff. It is shown that the introduction of solar energy by tourism businesses significantly increases their profits and competitiveness, reduces electricity costs, significantly improves the quality of services, increases the level of tourist service in rural areas. The need for state support and investment for the development of renewable energy sources in rural areas and green rural tourism is substantiated.

A 60‐Year Cycle in the Meteorite Fall Frequency Suggests a Possible Interplanetary Dust Forcing of the Earth's Climate Driven by Planetary Oscillations

AbstractOne of the most famous climate oscillations has a period of about 60 years. Although this oscillation might emerge from internal variability, increasing evidence points toward a solar or astronomical origin, as also argued herein. We highlight that the orbital eccentricity of Jupiter presents prominent oscillations with a period of quasi 60 years due to its gravitational coupling with Saturn. This oscillation is found to be well correlated with quite a number of climatic records and also with a 60‐year oscillation present in long meteorite fall records relative to the periods 619–1943 CE. Since meteorite falls are the most macroscopic aspect of incoming space dust and their motion is mostly regulated by Jupiter, we propose that the interplanetary dust influx also presents a 60‐year cycle and could be forcing the climate to oscillate in a similar manner by modulating the formation of the clouds and, therefore, the Earth's albedo.

Two Strengths of Ordinary Chondritic Meteoroids as Derived from Their Atmospheric Fragmentation Modeling

Abstract The internal structure and strength of small asteroids and large meteoroids is poorly known. Observation of bright fireballs in the Earth’s atmosphere can explore meteoroid structure by studying meteoroid fragmentation during the flight. Earlier evaluations showed that the meteoroid’s strength is significantly lower than that of the recovered meteorites. We present a detailed study of atmospheric fragmentation of seven meteorite falls, all ordinary chondrites, and 14 other fireballs, where meteorite fall was predicted but the meteorites, probably also ordinary chondrites, were not recovered. All observations were made by the autonomous observatories of the European Fireball Network and include detailed radiometric light curves. A model, called the semiempirical fragmentation model, was developed to fit the light curves and decelerations. Videos showing individual fragments were available in some cases. The results demonstrated that meteoroids do not fragment randomly but in two distinct phases. The first phase typically corresponds to low strengths of 0.04–0.12 MPa. In two-thirds of cases, the first phase was catastrophic or nearly catastrophic with at least 40% of mass lost. The second phase corresponds to 0.9–5 MPa for confirmed meteorite falls and somewhat lower strengths, from about 0.5 MPa, for smaller meteoroids. All of these strengths are lower than the tensile strengths of ordinary chondritic meteorites cited in the literature, 20–40 MPa. We interpret the second phase as being due to cracks in meteoroids and the first phase as a separation of weakly cemented fragments, which reaccumulated at the surfaces of asteroids after asteroid collisions.

The Rate of Falls of Meteorites and Bolides

We perform a statistical analysis of 926 confirmed falls of meteorites that occurred in the period 1860 to 2017. The distribution of meteorites over masses is approximated with a lognormal law. It has been shown that the mean interval between the detections of falls of Chelyabinsk-like meteorites is ~25 years. The time dependence of the annual number of meteorite falls is analyzed with the autocorrelation method. The (10–11)-year periodicity has been found for a group of H-chondrites and iron and iron-stone meteorites in the interval 1860 to 1960. The distributions of the number of recorded falls of meteorites over years, months, and time of day are compared to the respective distributions for bolides. The number of bolides is largest in 2005 and 2015, which suggests that there is a cycle 10−11 years long in the distribution of the bolide numbers over years. It has been noticed that more meteorites fall during the time interval from noon to midnight and in the spring-and-summer season. The number of recorded bolides does not depend on the time of day and season.

The meteorite of Barcelona (1704): History, discovery, and classification

AbstractOn Christmas Day 1704, at 17 h (UT), a meteorite fell in Terrassa (about 25 km NW of Barcelona). The meteorite fall was seen and heard by many people over an area of several hundred kilometers and it was recorded in several historical sources. In fact, it was interpreted as a divine sign and used for propaganda purposes during the War of the Spanish Succession. Although it was believed that meteorite fragments were never preserved, here we discuss the recent discovery of two fragments (49.8 and 33.7 g) of the Barcelona meteorite in the Salvador Cabinet collection (Botanic Institute of Barcelona). They are very well preserved and partially covered by a fresh fusion crust, which suggests a prompt recovery, shortly after the fall. Analysis of the fragments has revealed that the Barcelona meteorite is an L6 ordinary chondrite. These fragments are among the oldest historical meteorites preserved in the world.

Structural transformations and magnetic properties of plastically deformed FeNi-based alloys synthesized from meteoritic matter

In this work we investigated FeNi-based alloys synthesized from the cosmic matter of Morasko Meteorite (MM). The fall of Morasko iron meteorite is one of the biggest known in Central Europe and it has been dated to take place about five thousand years ago. It is known that iron meteorites contain hard magnetic tetrataenite phase (L10 FeNi), which has not been synthesized on the Earth in significant amount in the bulk form yet, because of very sluggish diffusion of Fe and Ni atoms below the disorder-order temperature of 320 °C. Firstly we doped the metallic part of Morasko Meteorite with Ni to obtain nearly equiatomic composition Fe51Ni49, which is the composition of pure tetrataenite.Further synthesis steps (melt-spinning, high pressure torsion, isothermal annealing at Ta = 320 °C for τa = 720 h) were undertaken to induce structural disorder and to observe changes in the structure/microstructure of the meteorite melt with nickel and its magnetic behavior. The presence of fcc FeNi with slightly varying lattice constant was confirmed at each step of the treatment. It evolved from the initial value of a = 3.589 ± 0.001 Å in the as-quenched state, through 3.591 ± 0.001 Å after 10 revolutions in the high pressure torsion process, to the maximum value of 3.593 ± 0.001 Å after 30 revolutions of anvils. No significant impact of further application of stress (50 revolutions) was noted, as the lattice parameter changed within the uncertainty limit. After annealing, the lattice parameter decreased to the initial value of the as-quenched sample (a = 3.589 ± 0.001 Å). The observed broadening of the peaks in the X-ray diffraction patterns may be attributed to the presence of microstrains and refinement of crystallites. Both contributions were determined using the Williamson-Hall method. In the initial state, the domain sizes were of about 100 ± 17 nm and diminished to 36 ± 11 nm after application of stress. Further isothermal annealing did not change the crystallites size, which was evaluated to be 35 ± 9 nm. Microstrains in the initial state were determined as (0.039 ± 0.017)10−3 and increased significantly to (0.562 ± 0.060)10−3 after 30 revolutions of anvils. Isothermal annealing decreased microstrains to (0.215 ± 0.071)10−3. After application of stress, the coercivity and remanence were enhanced, while subsequent isothermal annealing caused their decrease. Moreover, severe plastic deformation facilitated saturation of magnetization. As-quenched sample reached saturation at a magnetic field of about 2 T, while for high pressure torsion processed alloy this value was significantly reduced.

The Žďár nad Sázavou meteorite fall: Fireball trajectory, photometry, dynamics, fragmentation, orbit, and meteorite recovery

AbstractWe report a comprehensive analysis of the instrumentally observed meteorite fall Žďár nad Sázavou, which occurred in the Czech Republic on December 9, 2014, at 16:16:45–54 UT. The original meteoroid with an estimated initial mass of 150 kg entered the atmosphere with a speed of 21.89 km s−1 and began a luminous trajectory at an altitude of 98.06 km. At the maximum, it reached −15.26 absolute magnitude and terminated after a 9.16 s and 170.5 km long flight at an altitude of 24.71 km with a speed of 4.8 km/s. The average slope of the atmospheric trajectory to the Earth's surface was only 25.66°. Before its collision with Earth, the initial meteoroid orbited the Sun on a moderately eccentric orbit with perihelion near Venus orbit, aphelion in the outer main belt, and low inclination. During the atmospheric entry, the meteoroid severely fragmented at a very low dynamic pressure 0.016 MPa and further multiple fragmentations occurred at 1.4–2.5 MPa. Based on our analysis, so far three small meteorites classified as L3.9 ordinary chondrites totaling 87 g have been found almost exactly in the locations predicted for a given mass. Because of very high quality of photographic and radiometric records, taken by the dedicated instruments of the Czech part of the European Fireball Network, Žďár nad Sázavou belongs to the most reliably, accurately, and thoroughly described meteorite falls in history.

Josef Stepling a Royal Society ještě jednou

This contribution offers an analysis and edition of the Latin original and Czech translation of already the second letter sent by Josef Stepling to James Short. The letters were found in the Archives of the Royal Society in London. The first dealt with the fall of meteorites in southern Bohemia, the second (subject of the current study) describes how the impact of Lisbon earthquake that took place on 1 November 1755 was felt in the west Bohemian spa town of Teplice. The author also traces Stepling’s later interest in this natural phenomenon.

Elemental composition, mineralogy and orbital parameters of the Porangaba meteorite

The main objective of this study is to provide data on the bulk elemental composition, mineralogy and the possible origin of the Porangaba meteorite, whose fall was observed at 17:35 UT on 9 January 2015 on several sites of the state of São Paulo in Brazil. The surface of the meteorite was mapped by Scanning Electron Microscopy (SEM) and optical microscopy. The mineralogy and the bulk elemental composition of the meteorite were studied using Energy-Dispersive and Wavelength-Dispersive X-ray Spectroscopy (EDS/WDS) together with Electron Back Scatter Diffraction (EBSD). The bulk elemental composition was also independently analysed by Atomic Absorption Spectrometry (AAS), Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Laser Ablation ICP MS (LA ICP-MS) and Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS). Based on the available visual camera records of the Porangaba meteorite fall, its orbit was tentatively calculated, and possible candidates for the source bodies in the Solar system were proposed. We also present a laboratory simulation of a Porangaba-like (L4 Ordinary Chondrite) meteor emission spectra. These can be used as benchmark spectra for the identification of meteor rock types through their comparison with meteor spectra recorded by high-speed video-cameras equipped with simple grating spectrographs.

Characterization of the matrix and fusion crust of the recent meteorite fall Ozerki L6

AbstractWe studied the interior and the fusion crust of the recently recovered Ozerki L6 meteorite using optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy, X‐ray diffraction (XRD), magnetization measurements, and Mössbauer spectroscopy. The phase composition of the interior and of the fusion crust was determined by means of SEM, XRD, and Mössbauer spectroscopy. The unit cell parameters for silicate crystals were evaluated from the X‐ray diffractograms and were found the same for the interior and the fusion crust. Magnetization measurements revealed a decrease of the saturation magnetic moment in the fusion crust due to a decrease of Fe‐Ni‐Co alloy content. Both XRD and Mössbauer spectroscopy show the presence of magnesioferrite in the fusion crust. The temperatures of cation equilibrium distribution between the M1 and M2 sites in silicates calculated using the data obtained from XRD and Mössbauer spectroscopy appeared to be in a good consistency: 553 and 479 K for olivine and 1213 and 1202 K for orthopyroxene.