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Airburst: A Powerful Phenomenon

An airburst is the detonation of an explosive device or a meteor in the air instead of on contact with the ground or target. The principal military advantage of an airburst 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.

Airburst artillery has a long history, dating back to the Napoleonic wars, when shrapnel shells were invented to increase the effectiveness of canister shot. Modern shells, though sometimes called “shrapnel shells”, actually produce fragments and splinters, not shrapnel. Air bursts were used in the First World War to shower enemy positions and men with shrapnel balls to kill the largest possible number with a single burst.

Air bursts are also used for nuclear weapons, as they create a larger blast wave and thermal radiation than ground bursts. The air burst is usually 100 to 1,000 m (330 to 3,280 ft) above the hypocenter to allow the shockwave of the fission or fusion driven explosion to bounce off the ground and back into itself, combining two wave fronts and creating a shockwave that is more forceful than the one resulting from a detonation at ground level.

The most powerful meteor air burst in the modern era was the 1908 Tunguska event. During this event a stony 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 Siberia. The resulting shock wave flattened an estimated 80 million trees over a 2,150 km2 (830 sq mi) area. 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 over Russia. If the bolide is large enough fragments may survive, as from both such meteorites.

Airbursts are a fascinating and powerful phenomenon that can have both destructive and awe-inspiring effects.

The effects of airbursts depend on the type and size of the device or meteor, the altitude of the detonation, and the distance from the target. Some of the main effects are:

• Thermal radiation: This is the emission of light and heat that can cause skin burns, eye injuries, and fires at considerable distances. Thermal radiation accounts for about 35 percent of the total energy yield of an airburst.
• Shock wave: This is the blast of air that travels outward from the explosion, creating a sudden change in pressure and wind speed. Shock waves can damage buildings, vehicles, and people by crushing, shattering, or hurling them. Shock waves also spread fires further by creating firestorms.
• Ionizing radiation: This is the emission of alpha, beta, gamma, and neutron rays that can penetrate matter and cause damage to living cells and DNA. Ionizing radiation can cause acute radiation sickness, cancer, and genetic mutations. Ionizing radiation accounts for about 5 percent of the total energy yield of an airburst.
• Electromagnetic pulse (EMP): This is a burst of electromagnetic radiation that can disrupt or damage electronic devices and systems. EMP can affect communication, navigation, power grids, and satellites. EMP is more pronounced for high-altitude airbursts.

Airbursts can have both immediate and long-term effects on the environment and human health. The extent of these effects depends on various factors such as weather conditions, terrain features, population density, and emergency response capabilities.