The Physics
An encyclopedia of scientific essays

Number of Nuclear Warheads

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Bibliographic Entry Result
(w/surrounding text)
Lamont-Havers, Melinda. Estimated Nuclear Weapons Stockpiles, 1990-2003. Coalition to Reduce Nuclear Dangers. "Nuclear Warheads:
1990, [US & USSR], 61,000
January 1997, Global Total, 35,300-38,000
2003 (projected) [US & Russia], 20,850"
(projected 2003)
The New York Times Almanac. New York: Penguin, 1999: 508. "Warheads Total 36,000" 36,000
Blackwill, Robert D. New Nuclear Nations: Consequences for US Policy. New York: Council on Foreign Relations, 1993: 36-37. "Potential New Nuclear Forces (Late 1990s-2000+) [total of entries on table, 234]" 234
(new nuclear nations ca. 2000)
Nuclear Weapons: Report of the Secretary-General. Cambridge, MA: Autumn Press, 1980: 27. "Total Warheads 37,000-50,000" 37,000–50,000
Table of US Nuclear Warheads, 1945-1996. Natural Resources Defence Council. "Year, 1969; Startegic Warheads, Total, 9,147;
Non-Strategic Warheads, 17,386;
Stockpiled Warheads, 26,533"
(US 1969)
"Year, 1987; Startegic Warheads, Total, 14,953;
Non-Strategic Warheads, 8,214;
Stockpiled Warheads, 23,167"
(US 1987)
"Year, 1996; Startegic Warheads, Total, 9,170;
Non-Strategic Warheads, 1,985;
Stockpiled Warheads, 11,155;
Awaiting Dismantlement, 2,542;
Intact, 13,697"
(US 1996)

A nuclear warhead is part of a missile that contains an atomic or hydorgen bomb. An atomic bombs explodes when fission occurs while a hydrogen bomb explodes when fusion occurs.

When a fission weapon explodes, one type of atom is split into new types with less total mass. The lost mass is transformed into energy according to Albert Einstein's famous equation, E = mc2, which shows that a little bit of mass is equivalent to a great deal of energy. (The constant c stands for the speed of light, 3 × 108 m/s.) The total energy released per fission is about 200 MeV, an tremendous amount of energy on the nuclear scale. The fission of one kilogram of uranium would release the energy equivalent to 17,000 metric tons of TNT.

In fusion weapons, two small atoms fuse together into a larger atom, releasing energy. This reaction occurs only at extremely high temperatures and is more expensive to make. The majority of nuclear weapons on earth are fusion weapons.

In 1979, OTA predicted the results of a nuclear warhead explosion. If a single megaton warhead exploded at ground level in a populous location, it could kill 220,000 people and injure 420,000. If it exploded in the air, the immediate death toll would be 470,000 people and the number injured would be 630,000. Those that survived would also be expose to radiaion. If an person is exposed to between 250 to 400 rems of radiation over a course of 7 days, there is a fifty percent chance they will die.

At present, the number of nuclear warheads on earth is on the order of 35,000. Most of these are owned by the United States and Russia, with China, France, and Great Britain contributing smaller numbers. Several new nations are known or suspected to have nuclear weapons.

Fanny Tsui -- 2000

Bibliographic Entry Result
(w/surrounding text)
Fact Sheet: Increasing Transparency in the U.S. Nuclear Weapons Stockpile [pdf]. Nuclear Posture Review. US Department of Defense. 3 May 2010. "As of September 30, 2009, the U.S. stockpile of nuclear weapons consisted of 5,113 warheads. This number represents an 84 percent reduction from the stockpile’s maximum (31,255) at the end of fiscal year 1967, and over a 75 percent reduction from its level (22,217) when the Berlin Wall fell in late 1989." 5,113
(US 2009)
(US 1967)
(US 1989)

Editor's Supplement -- 2010