Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
Meteor air burst
A meteor air burst is an air burst caused by a meteoroid exploding within a planetary body's atmosphere after entering, before actually colliding with the planetary surface (lithosphere or hydrosphere). It is a type of impact event that generates a measurable shock wave but does not leave behind a typical crater or structure in the crust.
Aerodynamic heating causes meteoroids to become so-called fireballs or bolides, with the brightest air bursts known as superbolides. Such meteoroids were originally asteroids and comets of a few to several tens of meters in diameter, which separates them from the much smaller and far more common "shooting stars" that usually burn up quickly upon atmospheric entry. 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. If the bolide is large and dense enough, it may survive long enough into the atmospheric entry to build up a spectacular mid-air explosion (i.e. air burst), or to impact the planetary surface as a meteorite and leave behind a distinct impact crater.
Prior to the 20th century, only a very small number of meteor air bursts was ever detected, and even fewer documented. The most powerful known meteor air burst in the modern era was the 1908 Tunguska event, during which a rocky meteoroid about 50–60 m (160–200 ft) in size exploded at an altitude of 5–10 km (16,000–33,000 ft) over a sparsely populated forest in the Podkamennaya Tunguska region of Central Siberia. The resulting shock wave flattened an estimated 30 million trees over a 2,150 km2 (830 sq mi) area, and may have killed 3 people. 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 meteor air bursts.
Meteoroids enter the Earth's atmosphere from outer space traveling at speeds of at least 11 km/s (24,610 mph) and often much faster. Despite moving through the rarified upper reaches of Earth's atmosphere the immense speed at which a meteor travels rapidly compresses the air in its path. The meteoroid then experiences what is known as ram pressure. As the air in front of the meteoroid is compressed its temperature quickly rises. This is not due to friction, rather it is an adiabatic process, a consequence of many molecules and atoms being forced to occupy a smaller space. Ram pressure and the very high temperatures it causes are the reasons few meteoroids make it all the way to the ground. Most simply burn up or are ablated into tiny fragments. Larger or more solid meteorites may explode instead.
The use of the term explosion is somewhat loose in this context, and can be confusing. This confusion is exacerbated by the tendency for airburst energies to be expressed in terms of nuclear weapon yields, as when the Tunguska airburst is given a rating in megatons of TNT. Large meteoroids do not explode in the sense of chemical or nuclear explosives. Rather, at a critical moment in its atmospheric entry the enormous ram pressure experienced by the leading face of the meteoroid converts the body's immense momentum into a force blowing it apart over a nearly instantaneous span of time. That is, the mass of the meteoroid suddenly ceases to move at orbital speeds when it breaks up. Conservation of energy implies much of this orbital velocity is converted into heat.
In essence, the meteoroid is ripped apart by its own speed. This occurs when fine tendrils of superheated air force their way into cracks and faults in the leading face's surface. Once this high pressure plasma gains entry to the meteoroid's interior it exerts tremendous force on the body's internal structure. This occurs because the superheated air now exerts its pressure over a much larger surface area, as when the wind suddenly fills a sail. This sudden rise in the force exerted on the meteoroid overwhelms the body's structural integrity and it begins to break up. The breakup of the meteoroid yields an even larger total surface area for the superheated air to act upon and a cycle of amplification rapidly occurs. This is the explosion, and it causes the meteoroid to disintegrate with hypersonic velocity, a speed comparable to that of explosive detonation.
Air bursts have been recognized as a significant impact threat by the planetary defense community since at least 2010, when the National Academy of Sciences, citing Boslough and Crawford, recommended that "Because recent studies of meteor airbursts have suggested that near-Earth objects as small as 30 to 50 meters in diameter could be highly destructive, surveys should attempt to detect as many 30- to 50-meter-diameter objects as possible."
The table from Earth Impact Effects Program (EIEP) estimates the average frequency of airbursts and their energy yield in kilotons (kt) or megatons (Mt) of TNT equivalent.
Hub AI
Meteor air burst AI simulator
(@Meteor air burst_simulator)
Meteor air burst
A meteor air burst is an air burst caused by a meteoroid exploding within a planetary body's atmosphere after entering, before actually colliding with the planetary surface (lithosphere or hydrosphere). It is a type of impact event that generates a measurable shock wave but does not leave behind a typical crater or structure in the crust.
Aerodynamic heating causes meteoroids to become so-called fireballs or bolides, with the brightest air bursts known as superbolides. Such meteoroids were originally asteroids and comets of a few to several tens of meters in diameter, which separates them from the much smaller and far more common "shooting stars" that usually burn up quickly upon atmospheric entry. 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. If the bolide is large and dense enough, it may survive long enough into the atmospheric entry to build up a spectacular mid-air explosion (i.e. air burst), or to impact the planetary surface as a meteorite and leave behind a distinct impact crater.
Prior to the 20th century, only a very small number of meteor air bursts was ever detected, and even fewer documented. The most powerful known meteor air burst in the modern era was the 1908 Tunguska event, during which a rocky meteoroid about 50–60 m (160–200 ft) in size exploded at an altitude of 5–10 km (16,000–33,000 ft) over a sparsely populated forest in the Podkamennaya Tunguska region of Central Siberia. The resulting shock wave flattened an estimated 30 million trees over a 2,150 km2 (830 sq mi) area, and may have killed 3 people. 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 meteor air bursts.
Meteoroids enter the Earth's atmosphere from outer space traveling at speeds of at least 11 km/s (24,610 mph) and often much faster. Despite moving through the rarified upper reaches of Earth's atmosphere the immense speed at which a meteor travels rapidly compresses the air in its path. The meteoroid then experiences what is known as ram pressure. As the air in front of the meteoroid is compressed its temperature quickly rises. This is not due to friction, rather it is an adiabatic process, a consequence of many molecules and atoms being forced to occupy a smaller space. Ram pressure and the very high temperatures it causes are the reasons few meteoroids make it all the way to the ground. Most simply burn up or are ablated into tiny fragments. Larger or more solid meteorites may explode instead.
The use of the term explosion is somewhat loose in this context, and can be confusing. This confusion is exacerbated by the tendency for airburst energies to be expressed in terms of nuclear weapon yields, as when the Tunguska airburst is given a rating in megatons of TNT. Large meteoroids do not explode in the sense of chemical or nuclear explosives. Rather, at a critical moment in its atmospheric entry the enormous ram pressure experienced by the leading face of the meteoroid converts the body's immense momentum into a force blowing it apart over a nearly instantaneous span of time. That is, the mass of the meteoroid suddenly ceases to move at orbital speeds when it breaks up. Conservation of energy implies much of this orbital velocity is converted into heat.
In essence, the meteoroid is ripped apart by its own speed. This occurs when fine tendrils of superheated air force their way into cracks and faults in the leading face's surface. Once this high pressure plasma gains entry to the meteoroid's interior it exerts tremendous force on the body's internal structure. This occurs because the superheated air now exerts its pressure over a much larger surface area, as when the wind suddenly fills a sail. This sudden rise in the force exerted on the meteoroid overwhelms the body's structural integrity and it begins to break up. The breakup of the meteoroid yields an even larger total surface area for the superheated air to act upon and a cycle of amplification rapidly occurs. This is the explosion, and it causes the meteoroid to disintegrate with hypersonic velocity, a speed comparable to that of explosive detonation.
Air bursts have been recognized as a significant impact threat by the planetary defense community since at least 2010, when the National Academy of Sciences, citing Boslough and Crawford, recommended that "Because recent studies of meteor airbursts have suggested that near-Earth objects as small as 30 to 50 meters in diameter could be highly destructive, surveys should attempt to detect as many 30- to 50-meter-diameter objects as possible."
The table from Earth Impact Effects Program (EIEP) estimates the average frequency of airbursts and their energy yield in kilotons (kt) or megatons (Mt) of TNT equivalent.