Why do atomic bombs explode in the air

The heart of a nuclear explosion reaches a temperature of several million degrees centigrade. Over a wide area the resulting heat flash literally vaporises all human tissue. People inside buildings or otherwise shielded will be indirectly killed by the blast and heat effects as buildings collapse and all inflammable materials burst into flames. Those in underground shelters who survive the initial heat flash will die as all the oxygen is sucked out of the atmosphere.

Outside the area of total destruction there will be a gradually increasing percentage of immediate survivors. However most of these will suffer from fatal burns, will be blinded, bleeding and suffering massive internal injuries. Survivors will be affected within a matter of days by radioactive fall-out. Radiation-induced cancers will affect many, often over twenty years later.

Nuclear weapons cause severe damage to the climate and environment on a scale incomparable to any other weapon: the Red Cross estimates that a billion people around the world could face starvation as a result of nuclear war.

Taking into account the effects a nuclear bomb would have, it is no surprise that CND campaigns against nuclear weapons. They are immoral and expensive weapons of mass destruction, which have no military or strategic function in the face of 21st century threats. Fires more likely to spread are those caused by thermal radiation passing through windows to ignite beds and overstuffed furniture inside houses.

Another possible source of fires, which might be more damaging in urban areas, is indirect. Blast damage to Stores, water heaters, furnaces, electrical circuits or gas lines would ignite fires where fuel is plentiful. Direct radiation occurs at the time of the explosion. It can be very intense, but its range is limited. For large nuclear weapons, the range of intense direct radiation is less than the range of lethal blast and thermal radiation effects.

However, in the case of smaller weapons, direct radiation may be the lethal effect with the greatest range. Direct radiation did substantial damage to the residents of Hiroshima and Nagasaki.

Human response to ionizing radiation is subject to great scientific uncertainty and intense controversy. It seems likely that even small doses of radiation do some harm. Fallout radiation is received from particles that are made radioactive by the effects of the explosion, and subsequently distributed at varying distances from the site of the blast. While any nuclear explosion in the atmosphere produces some fallout, the fallout is far greater if the burst is on the surface, or at least low enough for the firebalI to touch the ground.

The significant hazards come from particles scooped up from the ground and irradiated by the nuclear explosion. The radioactive particles that rise only a short distance those in the "stem" of the familiar mushroom cloud will fall back to earth within a matter of minutes, landing close to the center of the explosion.

Such particles are unlikely to cause many deaths, because they will fall in areas where most people have already been killed. However, the radioactivity will complicate efforts at rescue or eventual reconstruction. The radioactive particles that rise higher will be carried some distance by the wind before returning to Earth, and hence the area and intensity of the fallout is strongly influenced by local weather conditions.

Much of the material is simply blown downwind in a long plume. Rainfall also can have a significant influence on the ways in which radiation from smaller weapons is deposited, since rain will carry contaminated particles to the ground. The areas receiving such contaminated rainfall would become "hot spots," with greater radiation intensity than their surroundings. Animals This frog mysteriously re-evolved a full set of teeth.

Animals Wild Cities Wild parakeets have taken a liking to London. Animals Wild Cities Morocco has 3 million stray dogs. Meet the people trying to help. Animals Whales eat three times more than previously thought. Environment Planet Possible India bets its energy future on solar—in ways both small and big. Environment As the EU targets emissions cuts, this country has a coal problem. Paid Content How Hong Kong protects its sea sanctuaries. History Magazine These 3,year-old giants watched over the cemeteries of Sardinia.

Magazine How one image captures 21 hours of a volcanic eruption. Science Why it's so hard to treat pain in infants. Science The controversial sale of 'Big John,' the world's largest Triceratops. Science Coronavirus Coverage How antivirals may change the course of the pandemic. Science Coronavirus Coverage U. Travel A road trip in Burgundy reveals far more than fine wine.

Travel My Hometown In L. Travel The last artists crafting a Thai royal treasure. Subscriber Exclusive Content. Why are people so dang obsessed with Mars? How viruses shape our world. The era of greyhound racing in the U. See how people have imagined life on Mars through history. See More.