Detection of Asteroid Impact Orbits Using Conditional Minimization of the Distance to the Earth

2020 ◽  
Vol 54 (6) ◽  
pp. 550-556
Author(s):  
A. P. Baturin
Keyword(s):  
Asteroid Impact ◽  
The Earth ◽  
Conditional Minimization

Chelyabinsk Meteorite

2021 ◽  
Author(s):  
Olga Popova
Keyword(s):  
Energy Deposition ◽  
Seismic Waves ◽  
The Body ◽  
Structure And Properties ◽  
Ural Mountains ◽  
Asteroid Impact ◽  
Unusual Event ◽  
The Earth ◽  
First Time

The asteroid impact near the Russian city of Chelyabinsk on February 15, 2013, was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding 1 million. On clear morning at 9:20 a.m. local time, an asteroid about 19 m in size entered the Earth atmosphere near southern Ural Mountains (Russia) and, with its bright illumination, attracted the attention of hundreds of thousands of people. Dust trail in the atmosphere after the bolide was tens of kilometers long and was visible for several hours. Thousands of different size meteorites were found in the areas south-southwest of Chelyabinsk. A powerful airburst, which was formed due to meteoroid energy deposition, shattered thousands of windows and doors in Chelyabinsk and wide surroundings, with flying glass injuring many residents. The entrance and destruction of the 500-kt Chelyabinsk asteroid produced a number of observable effects, including light and thermal radiation; acoustic, infrasound, blast, and seismic waves; and release of interplanetary substance. This unexpected and unusual event is the most well-documented bolide airburst, and it attracted worldwide attention. The airburst was observed globally by multiple instruments. Analyses of the observational data allowed determination of the size of the body that caused the superbolide, its velocity, its trajectory, its behavior in the atmosphere, the strength of the blast wave, and other characteristics. The entry of the 19-m-diameter Chelyabinsk asteroid provides a unique opportunity to calibrate the different approaches used to model meteoroid entry and to calculate the damaging effects. The recovered meteorite material was characterized as brecciated LL5 ordinary chondrite, in which three different lithologies can be distinguished (light-colored, dark-colored, and impact-melt). The structure and properties of meteorites demonstrate that before encountering Earth, the Chelyabinsk asteroid had experienced a very complex history involving at least a few impacts with other bodies and thermal metamorphism. The Chelyabinsk airburst of February 15, 2013, was exceptional because of the large kinetic energy of the impacting body and the damaging airburst that was generated. Before the event, decameter-sized objects were considered to be safe. With the Chelyabinsk event, it is possible, for the first time, to link the damage from an impact event to a well-determined impact energy in order to assess the future hazards of asteroids to lives and property.

The Biography of the Earth

2021 ◽  
pp. 200-213
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Small Mammals ◽  
Ecological Niche ◽  
Late Jurassic ◽  
Big Bang ◽  
Ecological Niches ◽  
Asteroid Impact ◽  
The Earth ◽  
The One ◽  
Extinction Events ◽  
The Universe

The story of the Phanerozoic Eon continues in this chapter with the Mesozoic Era. The first period in the Mesozoic, the Triassic, was bookended by two extinction events, the one at the beginning, discussed in the prior chapter at the end of the Permian Period, the Great Dying, and then another at the end of the period, related to the further breakup of Pangea. Dinosaurs evolved and diversified during the Mesozoic to occupy nearly each and every ecological niche on the planet, with large dinosaurs and small dinosaurs, ones that flew, those that ate vegetation, and those that preyed upon the herbivores—making this time a dino-dominated age. In the late Jurassic Period, small mammals, many of them insectivores, were starting to become prevalent. The era ended with a “big bang” of a different type than is theorized as the start of the universe—with the Chicxulub asteroid impact 66 million years ago that ended the lives of most of the dinosaurs, the non-avian lines, and opened up new ecological niches for the next “masters of the universe,” the mammals.

Biography of the Earth

2021 ◽  
pp. 214-228
Author(s):  
Elisabeth Ervin-Blankenheim
Keyword(s):  
Mass Extinction ◽  
Ice Sheets ◽  
Late Cenozoic ◽  
Ice Ages ◽  
Quaternary Period ◽  
Asteroid Impact ◽  
The Earth ◽  
Ecological Resources ◽  
Extinction Event ◽  
Cenozoic Era

The last era in the Phanerozoic Eon, the Cenozoic Era, is detailed in this chapter. The rise and radiation of the mammals occurred during Cenozoic after the devastation wrought by the Chicxulub Asteroid impact at the end of the Mesozoic Era. Ecological resources and niches vacated by the dinosaurs because of the mass extinction were filled by the mammals with concurrent developments in plants. Changes in climate and the mid-Miocene warming happened mid-era, then drying out and opening of grasslands followed by a plunge into ice ages and the Pleistocene extinction event. The late Cenozoic witnessed the development of humankind as the great ice sheets from the Pleistocene started to melt and the climate warm. The planet started to look similar to how it appears to humans today, and the current age of the Earth is the Cenozoic Era, Quaternary Period, Holocene Epoch, Meghalayan Age.

5. The threat from space

2014 ◽  
pp. 88-109
Author(s):  
Bill McGuire
Keyword(s):  
Circular Orbits ◽  
Asteroid Impact ◽  
The Earth ◽  
The Future ◽  
Near Earth Asteroids ◽  
Earth Potential ◽  
Asteroids And Comets

‘The Threat from Space’ considers the threat of asteroids and comets colliding with Earth. Potential impacts of Near Earth Asteroids, with almost circular orbits, have been identified, but the threat from comets, which follow strongly elliptical paths, is uncertain. The Mexican asteroid impact 65 million years ago is thought to have wiped out two-thirds of all species living at the time. The Earth will be hit again at some point in the future, but how will it affect us? This will depend upon three things: the size of the object, how quickly it is travelling, and whether it hits the land or the ocean.

Didymos Gravity Science through Ground-based and Satellite-to-Satellite Doppler Tracking

2020 ◽  
Author(s):  
Paolo Tortora ◽  
Igor Gai ◽  
Marco Lombardo ◽  
Marco Zannoni ◽  
Ian Carnelli ◽  
...  
Keyword(s):  
Gravity Field ◽  
Satellite Link ◽  
Asteroid Impact ◽  
Ground Station ◽  
The Earth ◽  
X Band ◽  
Post Impact ◽  
Doppler Tracking ◽  
Achievable Accuracy

<p>Hera is ESA’s contribution to an international effort supported by ESA and NASA named Asteroid Impact and Deflection Assessment (AIDA). NASA’s DART mission will first perform a kinetic impact on Didymos secondary, nicknamed Didymoon, then Hera will follow-up with a detailed post-impact survey, to fully characterize this planetary defense technique. Two CubeSats will be deployed by the Hera spacecraft once the Early Characterization Phase has completed.</p><p>The Hera spacecraft communicates with the ground station on the Earth by means of a standard two-way X-band system. The microwave signal is sent to the S/C from a ground antenna and coherently retransmitted back to Earth, where Doppler (the key observable for gravity science) and range measurements are obtained. In addition, Hera will track the two CubeSats by means of a space-to-space inter-satellite link (ISL). This represents a very nice add-on to the gravity investigation carried out by means of Hera tracking observables as the Doppler effect that affects the inter-satellite link contains the information on the dynamics of the system, i.e. masses and gravity field of Didymos primary and secondary.</p><p>We describe here the mission scenario for the gravity science experiments to be jointly carried out by the three mission elements, i.e. Hera, CubeSat#1 (named Juventas) and CubeSat#2, via Ground-based and Satellite-to-Satellite Doppler Tracking. Also, our results and achievable accuracy for the estimation of the mass and gravity field of Didymos primary and secondary are presented.</p>

A search for shocked quartz grains and impact ejecta in early Silurian sediments on Gotland, Sweden

1994 ◽  
Vol 131 (3) ◽  
pp. 361-367 ◽  
Author(s):  
Birger Schmitz ◽  
Lennart Jeppsson ◽  
Johan Ekvall
Keyword(s):  
Lateral Spreading ◽  
Asteroid Impact ◽  
The Earth ◽  
Planar Shock ◽  
Impact Ejecta ◽  
Single Grain ◽  
Shocked Quartz ◽  
Impact Events ◽  
Impact Origin ◽  
Quartz Grains

AbstractAll bentonite and bentonite-resembling layers thicker than a few millimetres from a 120m-thick Early Silurian sequence on Gotland, Sweden, were searched for shocked quartz grains of comet or asteroid impact origin. Although more than 200000 quartz grains from 86 bentonite samples were studied, not one single grain with multiple planar shock features was found. The studied sequence represents sedimentation during a period of about 2 million years. Impact frequencies, estimated from the cratering record and astronomical observations, indicate that during a 2-myr- period on average 20 comet or asteroid bodies larger than 0.5 km in diameter strike the Earth. The number of smaller impacting bodies is many times higher. In the light of this high frequency of impacts, the absence of any shocked-quartz-bearing fallout layer in our sequence indicates that lateral spreading of such ejecta is relatively restricted during small- and medium-scale impact events.The results also show that shocked quartz in general is absent or extremely rare in volcanic ash. This strengthens the case for an impact-related origin of shocked quartz grains in the Cretaceous–Tertiary boundary days.

Projecting Asteroid Impact Corridors onto the Earth

2019 ◽  
Author(s):  
Clemens M. Rumpf ◽  
Donovan Mathias ◽  
Davide Farnocchia ◽  
Steven Chesley
Keyword(s):  
Asteroid Impact ◽  
The Earth

scholarly journals Worlds in Collision and the Origin of Life

2019 ◽  
Author(s):  
Rainer Kühne
Keyword(s):  
Amino Acids ◽  
Gamma Ray ◽  
Rna World ◽  
Ice Age ◽  
Small Peptides ◽  
Primitive Earth ◽  
Asteroid Impact ◽  
The Earth ◽  
Terrestrial Life ◽  
Unicellular Organisms

Earth and Moon were formed 4.6 billion years ago by the collision of the two protoplanets Gaia and Theia. Afterwards the Earth formed a crust where colliding comets provided the water of the oceans. This Hadean Eon was terminated 3.9 billion years ago during the Late Heavy Bombardment when an eccentric orbit of Jupiter caused a bombardment of the Earth by asteroids. Soon thereafter, 3.8 billion years ago, there is geochemical evidence of terrestrial life which performed photosynthesis. The terrestrial life witnessed and survived several cataclysms including the snowball Earth 760 to 580 million years ago, an ice age 440 million years ago which was possibly caused by a gamma-ray burst, and an asteroid impact 65 million years ago which generated the Chicxulub crater and contributed to the extinction of the dinosaurs. The 1908 Tunguska explosion was caused by a small stony asteroid. Amino acids, purines, pyrimidines and sugars, but no proteins, nucleotides or extraterrestrial unicellular organisms were detected in meteorites. This argues against the hypothesis of panspermia. The synthesis of amino acids, small peptides, purines and pyrimidine ribonucleotides under conditions of the primitive Earth (Stanley Miller experiments) and the polymerization of RNA nucleotides on clay minerals suggests that viroids and an RNA world could have existed during the Hadean Eon.

The motion of a lunar orbiter

1966 ◽  
Vol 25 ◽  
pp. 373
Author(s):  
Y. Kozai
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Artificial Satellite ◽  
Equations Of Motion ◽  
Triaxial Ellipsoid ◽  
The Moon ◽  
Secular Motion ◽  
The Earth ◽  
Close Satellite ◽  
The Mean

The motion of an artificial satellite around the Moon is much more complicated than that around the Earth, since the shape of the Moon is a triaxial ellipsoid and the effect of the Earth on the motion is very important even for a very close satellite.The differential equations of motion of the satellite are written in canonical form of three degrees of freedom with time depending Hamiltonian. By eliminating short-periodic terms depending on the mean longitude of the satellite and by assuming that the Earth is moving on the lunar equator, however, the equations are reduced to those of two degrees of freedom with an energy integral.Since the mean motion of the Earth around the Moon is more rapid than the secular motion of the argument of pericentre of the satellite by a factor of one order, the terms depending on the longitude of the Earth can be eliminated, and the degree of freedom is reduced to one.Then the motion can be discussed by drawing equi-energy curves in two-dimensional space. According to these figures satellites with high inclination have large possibilities of falling down to the lunar surface even if the initial eccentricities are very small.The principal properties of the motion are not changed even if plausible values ofJ3andJ4of the Moon are included.This paper has been published in Publ. astr. Soc.Japan15, 301, 1963.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

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