File Name: article about comets asteroids and meteors .zip
November 20, Asteroids and comets have a few things in common. They are both celestial bodies orbiting our Sun, and they both can have unusual orbits, sometimes straying close to Earth or the other planets. They are both "leftovers"—made from materials from the formation of our Solar System 4.
The study of asteroidal and cometary material entering into Earth's atmosphere has scientific and social importance. The observation and study of the impact of meteoroids with our planet is a way of studying geophysics and planetary geology without spaceships. This article describes the progress of the installation of the Mexican Meteor Network Citlalin Tlamina. At medium and long term, the aim of this network is to cover the entire national territory with stations that allow us to record the entry of meteoroids into Earth's atmosphere.
This seeks to: a study the meteoroid-atmosphere interaction, b determine impactor's physical properties; c analyze flows and Radiant deviations of known meteor showers, d find or ratify new meteor showers; e recover and study meteorites, f study the interaction of the shock wave with the ground by analyzing seismograms; g report people in real time or near the occurrence of fireballs and fragmentation of meteoroids in the atmosphere, avoiding the fear of this phenomenon and provide support for Civil Protection, h find areas of opportunity that can use the images captured by the cameras weather, bird migration, etc.
When a comet, asteroid or meteoroid collides with a planet several things can happen depending on the mass, velocity and composition of the object, if the planet or moon has an atmosphere or not, and the angle of impact. In airless bodies, like Mercury or the Moon, all objects that strike their surfaces produce impact craters whose sizes range from centimeters to hundreds and even thousands of kilometers across.
In bodies with atmosphere, the encounter with a meteoroid or small body asteroid or comet can produce impact craters, meteorites, meteors and fragmentation of the original body, depending on the kinetic energy of the object.
Meteors, also called shooting stars, are bright trails in the sky produced by the heating and incandescence of micrometeorites and meteoroids in the terrestrial atmosphere. A meteoroid is asteroidal o cometary material whose size is between 2 mm and meters long Ceplecha et al. These objects generally evaporate at heights between 80 and km Glass, Objects of less than 2 mm are known as micrometeorites Hutchinson, Objects between 0.
If a meteoroid, or a fragment of it, survives atmospheric ablation and can be recovered on the ground, that piece is called a meteorite. Meteorites can be classified according to their materials or according to their origin. Following the first criterion, they fall into one of three types: iron iron-nickel , stone silicates and stony-iron iron, nickel and silicates Weisber, According to their origin, meteorites are classified into two groups; differentiated and undifferentiated meteorites.
Each one of these groups has subdivisions. Undifferentiated meteorites can be chondrites which in turn are divided into 5 types and primitive achondrites. Differentiated meteorites are divided into achondrites, iron meteorites and stony-iron meteorites Cervantes, The study of meteorites has been and will be very important for understanding the physical and chemical conditions that existed inside the primitive solar nebula, to estimate the age of formation of the solar system and to model the interiors of planets and moons Hutchinson, ; Taylor ; Pater and Lissauer, The impact velocity of a meteoroid or a small body with another planetary body depends on the escape velocity of the latter, its heliocentric orbital velocity and velocity of the impactor at the heliocentric distance of the impacted body.
For Earth, the minimum speed of impact is the escape velocity When meteoroids and asteroids up to a few tens of meters in diameter interact with the Earth's atmosphere, they slow down as they go into more dense layers. The friction between a meteoroid or asteroid or comet and air, heat the object up to the material is ablated.
The aerodynamic pressure of the atmosphere on small asteroids or meteoroids can be greater or equal to their internal strength; in this case the object fragment suddenly in the atmosphere producing shock waves. The fragmentation of the object is not immediate; the pressure wave must be transmitted into the body. It occurs fairly quickly because the propagation velocity of such waves is between m s -1 and m s -1 , even m s -1 in iron meteorites Flynn et al. At first, the fragments have the same shock wave, but as they separate laterally, more space is among them until each fragment acquires its own shock wave.
When this sudden separation occurs it is said that the object explodes Melosh, ; Hills and Goda, When the object that is broken is tens of meters long, its fragments may hit the ground with enough kinetic energy to create several impact craters Passey and Melosh, On our planet there are around a dozen of such structures, which are known as fields of craters.
During the XX and XXI centuries, a series of events showed the importance of collisions between planets and minor planets comets and asteroids.
On the morning of June 30, , an object of between 50 and m suddenly broken at a height of km with an energy of Mt TNT Svetsov and Shuvalov, The blast completely destroyed the material so none impact crater was formed, but the shock wave produced during the fragmentation had the enough energy to break down trees inside an area of km 2 Farinella et al. That same shock wave produced an earthquake of magnitude 4. This event did not created impact craters, at least not recognizable currently but the energy of the explosion was much more modest than Tunguska's, probably some few kilotons of TNT.
At this point, it is important to emphasize that this event is known thanks to a catholic missionary who arrived at the scene a few days after, and made a report that was published in the Vatican newspaper in Cordero and Poveda, A more recent event occurred on 15 February, on Chelyabinsk region, Russia.
It is estimated that a rocky chondritic asteroid of about The shock wave, produced by the explosion of this asteroid in the atmosphere, caused cracks in walls and broken windows.
Shattered glasses hurt more than one thousand and five hundred persons Popova et al. On February 10, , near the border between Puebla and Hidalgo States, Mexico, people heard an explosion that alarmed the population. Some kilometers away, some persons observed a bolide. This event may have been the sudden fragmentation of an object in the atmosphere. It is estimated that the explosion could have released an energy of a few kilotons. While studying this event we realized the social value of alerting the population about such phenomena because it cause great fear and can represent many hours of lost work for members of Civil Protection Cordero et al.
On February 22, another fireball was observed in Mexico, this time near the border between Aguascalientes and Zacatecas. This last event reaffirmed the need for a continuous monitoring system of meteors and fireballs. There are several ways to detect the entry of meteoroids and small bodies in the Earth's atmosphere: naked eye, photographs, videos, radar, lidar and infrasound. Putting aside the observations with the naked eye, which is obviously the oldest technique Yang, et al.
The next step was the use of networks of video cameras that allow monitoring the sky in a more systematic way, among such networks are the European meteor video observation network EDMON and the IMO Video Meteor Network that include networks in several European countries. Currently, we are working to have the Mexican Meteor Network whose informal name is Citlalin Tlamina " meteor " in nahuatl language.
With this network, we want to a Determine values of meteoroid's parameters to be used in numerical modeling of the dynamics of these objects through Earth's atmosphere, b determine the conditions under which seismic waves are created due to the shock wave that is produced by the fragmentation of a meteoroid in the atmosphere; c understand the coupling of atmospheric shock wave with the ground, and the information that can be obtained about height and energy of the explosion, d know the region meteoroids come from main belt asteroids, Earth's neighborhood, etc.
Buil gives a series of recommendations to choose the most suitable photographic equipment and lenses to observe meteors.
Once we have this equipment, the next action was to design a base to protect the cameras. We chose to form a station with 6 cameras because, during previous observation campaigns, we realized that 4 cameras were not enough to cover the entire free sky.
According to our observations, we needed 6 cameras to get it. The fields of vision of these 6 cameras overlap a bit, but this, far from being a problem is an advantage as it is likely that a meteor can be seen by two or more cameras at each station.
Conditions of high temperature and humidity were considered in our design. The aim was then design the mechanical interface of the monitoring station used to observe meteors and fireballs entering the Earth's atmosphere.
At first, it was thought to use the cameras to observe meteors at night, but in the near future the base will be modify to perform daytime observations. No other factors were considered, but more constraints can be regarded according to how the system works. We generated some conceptual solutions for each requirement.
After evaluating, the following solutions were selected because of their simplicity, low cost and easy manufacture:. In order to protect the cameras from the environment, acrylic cages were used, because it is a low cost and simple manufacture material Figure 2.
Another solution, perhaps more aesthetic, was to use a dome made of acrylic, but it was about 3 times more expensive and more difficult to solve the problem of condensation inside. In order to keep a functional temperature for the cameras, they were attached to an aluminum plate that dissipates heat. Besides, this plate is cooled by a fan that produces forced convection Figure 3. Also we implemented over the cages a cover of reflective material to reduce heating because of Sun light.
The first option was to implement an environmental conditioning system but, once again, the cost was the main issue. Silica gel was used to absorb humidity and to avoid condensation inside cages. The mass quantity of silica that is necessary to absorb humidity inside the cage is 15 mg.
To prevent ingress of water vapor, joints between the acrylic cages and glass were sealed with silicone, and joints between acrylic cages and their metal base were sealed placing a plastic seal and silicone. We thought to use an electric air dryer system but it was more complicated for maintenance. Each camera is connected to a single PC to prevent interference of signals from two or more cameras.
At the moment, all data is stored in internal disks of each PC, then this information is down into an external disk. After that, videos are classified clouds, rain, lightning, insects, etc.
We only analyzed videos of meteors. The monitoring station designed has: a Individual compartments or cages for each camera, b humidity cages that contain silica gel, c individual and independent elevation of each horizontal camera, and d cooling system Figure 5. This arrangement allows to move and provide maintenance of each camera independently Figure 6. These particles ablate totally in the atmosphere at the same time they produce easily detectable meteors.
The maximum flow of the fall of these particles occurred this year on the morning of May 6 th. Taking the advantage of this event, we used the instrument described above. Due to weather conditions, we recorded only two meteors, one of them is shown in the Figure 8. To obtain this figure, we use the Maxim DL software. Since that day, we have made a series of night observations. This has allowed us to realize about the strengths and weaknesses of the design, and it has shown us the direction of future work.
The monitoring station design protects the cameras from environment, ensuring their correct operation and allowing the observation of meteors and fireballs produced by meteoroids and small asteroids that enter into the Earth's atmosphere. The covers of reflective material used over the acrylic cages improve their durability despite the sun light.
The fans and the silica gel maintain the environment inside the cages in adequate conditions for the cameras performance. It should be mentioned that our main constraint was cost and, as a consequence of that, the station needs to be monitored as regularly as possible in order to decide when to change the acrylic cages or to add or replace the silica gel. The cost of the monitoring station is very low, because of the low cost materials used and its simple configuration.
The monitoring stations could be located almost anywhere due to cameras are completely isolated from the external environment, avoiding inclement weather inside the cages. The design is being tested since May 6, , day when we observed the eta Aquarids. On this occasion only two meteors were recorded because bad weather conditions very cloudy sky. In the coming months, the current base will be improved to solve some problems and a new base will be design based on experience.
All authors thank anonymous reviewers for their helpful and thoughtful comments and suggestions. One of the authors, G.
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Jump to navigation. Could a meteorite collision really mean the end of life on Earth? Read this to find out what happens when small meteorites collide with Earth, and just how much damage a big one could do. But on 15 February , we were lucky. Although many people were injured by falling glass, the damage was nothing compared to what had happened in Siberia nearly one hundred years ago. Another relatively small object approximately 50 metres in diameter exploded in mid-air over a forest region, flattening about 80 million trees. If it had exploded over a city such as Moscow or London, millions of people would have been killed.
Planetary scientists sharing ideas and discoveries. Bennu—Active Asteroid by Linda M. Martel CosmoSparks Report - Researchers support naming a new CY group of carbonaceous chondrite meteorites that may be similar to near-Earth asteroid Ryugu, the target of sample return in December Martel CosmoSparks Report - Laboratory heating experiments track the release of labile elements in meteorite samples to better understand asteroid evolution, with relevance to future handling of samples returned from asteroid Bennu. Active Asteroids by Linda M.
In our solar system there are billions, possibly trillions, of rogue objects orbiting the sun. These spacefarers are too small to be called planets and are given the names of comets, asteroids, meteoroids, and if they reach Earth, meteors or meteorites. With so many labels, it's easy to forget which is which. Asteroids: These are the rocky and airless leftovers from the formation of planets in our solar system.
Comets Reading Answers While comets observed in our time only accent the irrationality of ancient fears, the worldwide portent symbolism of the comet answers so completely to the archetypal Great Comet Venus as to logically preclude the customary explanations of these fears. Benefits of playing Spelling With Comet: - Enrich your vocabulary.
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