or H-bomb or thermonuclear bomb

Weapon whose enormous explosive power is generated by the nuclear fusion of hydrogen isotopes. The high temperatures required for the fusion reaction are produced by detonating an atomic bomb (which draws its energy from nuclear fission). The bomb's explosion produces a blast that can destroy structures within a radius of several miles, an intense white light that can cause blindness, and heat fierce enough to set off firestorms. It also creates radioactive fallout that can poison living creatures and contaminate air, water, and soil. Hydrogen bombs, which may be thousands of times more powerful than atomic bombs, can be made small enough to fit in the warhead of a ballistic missile (see ICBM) or even in an artillery shell (see neutron bomb). Edward Teller and other U.S. scientists developed the first H-bomb and tested it at Enewetak atoll (Nov. 1, 1952). The Soviet Union first tested an H-bomb in 1953, followed by Britain (1957), China (1967), and France (1968). Most modern nuclear weapons employ both fusion and fission.

Learn more about hydrogen bomb with a free trial on Britannica.com.

A cobalt bomb, a type of salted bomb, is a nuclear weapon originally proposed by physicist Leó Szilárd, who suggested that it would be capable of destroying all life on Earth. The weapon's tamper would be made of ordinary cobalt metal, which would be transmuted into the radioactive isotope ⁶⁰Co, producing deadly fallout.

Mechanism

The cobalt tamper would be transmuted into the isotope ⁶⁰Co upon initiation and bombardment by neutron radiation. ⁶⁰Co decays into an excited ⁶⁰Ni by beta decay. The excited ⁶⁰Ni then transitions to a ground state ⁶⁰Ni, releasing gamma radiation.

Other isotopes could also be used for salted bombs, including gold-197, tantalum-181, and zinc-64.

Weapon of global destruction

The fallout would have a half-life of 5.27 years and would be intensely radioactive, a combination which caused Szilárd to suggest that such bombs could wipe out all life on the planet. Critics of the cobalt bomb concept point out that the mass needed would still be unreasonably large: 1 gram of ⁶⁰Co per square kilometer of Earth's surface is 510 tonnes, and fallout does not reach all areas in equal proportions and dispersement (winds, etc.) . The sheer size and cost of such a weapon makes it unlikely to be built, although it is technically possible because there is no maximum size limit for a thermonuclear bomb.

Notes

External links

• "Dr Strangelove and the real Doomsday machine": a review in the TLS by Christopher Coker, August 8, 2007
• Types of Nuclear Weapons Cobalt Bombs and other Salted Bombs, May 1998