A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission ("atomic") bomb test released the same amount of energy as approximately 20,000 tons of TNT. The first thermonuclear ("hydrogen") bomb test released the same amount of energy as approximately 10,000,000 tons of TNT.

A modern thermonuclear weapon weighing little more than can produce an explosive force comparable to the detonation of more than 1.2 million tons (1.1 million metric tons) of TNT. Thus, even a small nuclear device no larger than traditional bombs can devastate an entire city by blast, fire and radiation. Nuclear weapons are considered weapons of mass destruction, and their use and control has been a major focus of international relations policy since their debut.

Only two nuclear weapons have been used in the course of warfare, both by the United States near the end of World War II. On 6 August 1945, a uranium gun-type device code-named "Little Boy" was detonated over the Japanese city of Hiroshima. Three days later, on 9 August, a plutonium implosion-type device code-named "Fat Man" was exploded over Nagasaki, Japan. These two bombings resulted in the deaths of approximately 200,000 Japanese people—mostly civilians—from acute injuries sustained from the explosions. The role of the bombings in Japan's surrender, and their ethical status, remain the subject of scholarly and popular debate.

Since the bombings of Hiroshima and Nagasaki, nuclear weapons have been detonated on over two thousand occasions for testing purposes and demonstrations. Only a few nations possess such weapons or are suspected of seeking them. The only countries known to have detonated nuclear weapons—and that acknowledge possessing such weapons—are (chronologically by date of first test) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, the People's Republic of China, India, Pakistan, and North Korea. In addition, Israel is also widely believed to possess nuclear weapons, though it does not acknowledge having them. One state, South Africa, has admitted to having previous fabricated nuclear weapons in the past, but has since disassembled their arsenal and submitted to international safeguards.

Types

There are two basic types of nuclear weapons: those which derive the majority of their energy from nuclear fission reactions alone, and those which use fission reactions to begin nuclear fusion reactions that produce a large amount of the total energy output.

Fission weapons

All existing nuclear weapons derive some of their explosive energy from nuclear fission reactions. Weapons whose explosive output is exclusively from fission reactions are commonly referred to as atomic bombs or atom bombs (abbreviated as A-bombs). This has long been noted as something of a misnomer, however, as their energy comes specifically from the nucleus of the atom.

In fission weapons, a mass of fissile material (enriched uranium or plutonium) is assembled into a supercritical mass—the amount of material needed to start an exponentially growing nuclear chain reaction—either by shooting one piece of sub-critical material into another (the "gun" method) or by compressing a sub-critical sphere of material using chemical explosives to many times its original density (the "implosion" method). The latter approach is considered more sophisticated than the former and only the latter approach can be used if the fissile material is plutonium.

A major challenge in all nuclear weapon designs is to ensure that a significant fraction of the fuel is consumed before the weapon destroys itself. The amount of energy released by fission bombs can range from the equivalent of less than a ton of TNT upwards of 500,000 tons (500 kilotons) of TNT.

Fusion weapons

The other basic type of nuclear weapon produces a large amount of its energy through nuclear fusion reactions. Such fusion weapons are generally referred to as thermonuclear weapons or more colloquially as hydrogen bombs (abbreviated as H-bombs), as they rely on fusion reactions between isotopes of hydrogen (deuterium and tritium). However, all such weapons derive a significant portion, and sometimes a majority, of their energy from fission. This is because a fission weapon is required as a "trigger" for the fusion reactions, and the fusion reactions can themselves trigger additional fission reactions.

Only six countries—United States, Russia, United Kingdom, People's Republic of China, France and India—have conducted thermonuclear weapon tests. (Whether India has detonated a "true", multi-staged thermonuclear weapon is controversial.) All thermonuclear weapons are considered to be much more difficult to successfully design and execute than primitive fission weapons.

Thermonuclear bombs work by using the energy of a fission bomb to compress and heat fusion fuel. In the Teller-Ulam design, which accounts for all multi-megaton yield hydrogen bombs, this is accomplished by placing a fission bomb and fusion fuel (tritium, deuterium, or lithium deuteride) in proximity within a special, radiation-reflecting container. When the fission bomb is detonated, gamma and X-rays emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. The ensuing fusion reaction creates enormous numbers of high-speed neutrons, which can then induce fission in materials not normally prone to it, such as depleted uranium. Each of these components is known as a "stage", with the fission bomb as the "primary" and the fusion capsule as the "secondary". In large hydrogen bombs, about half of the yield, and much of the resulting nuclear fallout, comes from the final fissioning of depleted uranium.

By chaining together numerous stages with increasing amounts of fusion fuel, thermonuclear weapons can be made to an almost arbitrary yield; the largest ever detonated (the Tsar Bomba of the USSR) released an energy equivalent of over 50 million tons (50 megatons) of TNT. Most thermonuclear weapons are considerably smaller than this, due to practical constraints arising from the space and weight requirements of missile warheads.

Other types

There are other types of nuclear weapons as well. For example, a boosted fission weapon is a fission bomb which increases its explosive yield through a small amount of fusion reactions, but it is not a fusion bomb. In the boosted bomb, the neutrons produced by the fusion reactions serve primarily to increase the efficiency of the fission bomb.

Some weapons are designed for special purposes; a neutron bomb is a thermonuclear weapon that yields a relatively small explosion but a relatively large amount of neutron radiation; such a device could theoretically be used to cause massive casualties while leaving infrastructure mostly intact and creating a minimal amount of fallout. The detonation of any nuclear weapon is accompanied by a blast of neutron radiation. Surrounding a nuclear weapon with suitable materials (such as cobalt or gold) creates a weapon known as a salted bomb. This device can produce exceptionally large quantities of radioactive contamination.

Most variation in nuclear weapon design is for the purpose of achieving different yields for different situations, and in manipulating design elements to attempt to minimize weapon size.

Weapons delivery

Nuclear weapons delivery—the technology and systems used to bring a nuclear weapon to its target—is an important aspect of nuclear weapons relating both to nuclear weapon design and nuclear strategy. Additionally, development and maintenance of delivery options is among the most resource-intensive aspects of a nuclear weapons program: according to one estimate, deployment costs accounted for 57% of the total financial resources spent by the United States in relation to nuclear weapons since 1940.

Historically the first method of delivery, and the method used in the two nuclear weapons actually used in warfare, was as a gravity bomb, dropped from bomber aircraft. This method is usually the first developed by countries as it does not place many restrictions on the size of the weapon and ''weapon miniaturization'' is something which requires considerable weapons design knowledge. It does, however, limit the range of attack, the response time to an impending attack, and the number of weapons which can be fielded at any given time.

With the advent of miniaturization, nuclear bombs can be delivered by both strategic bombers and tactical fighter-bombers, allowing an air force to use its current fleet with little or no modification. This method may still be considered the primary means of nuclear weapons delivery; the majority of U.S. nuclear warheads, for example, are free-fall gravity bombs, namely the B61.

More preferable from a strategic point of view is a nuclear weapon mounted onto a missile, which can use a ballistic trajectory to deliver the warhead over the horizon. While even short range missiles allow for a faster and less vulnerable attack, the development of long-range intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) has given some nations the ability to plausibly deliver missiles anywhere on the globe with a high likelihood of success.

More advanced systems, such as multiple independently targetable reentry vehicles (MIRVs), allow multiple warheads to be launched at different targets from one missile, reducing the chance of a successful missile defense. Today, missiles are most common among systems designed for delivery of nuclear weapons. Making a warhead small enough to fit onto a missile, though, can be a difficult task.

Tactical weapons have involved the most variety of delivery types, including not only gravity bombs and missiles but also artillery shells, land mines, and nuclear depth charges and torpedoes for anti-submarine warfare. An atomic mortar was also tested at one time by the United States. Small, two-man portable tactical weapons (somewhat misleadingly referred to as suitcase bombs), such as the Special Atomic Demolition Munition, have been developed, although the difficulty of combining sufficient yield with portability limits their military utility.

Nuclear strategy

Nuclear warfare strategy is a set of policies that deal with preventing or fighting a nuclear war. The policy of trying to prevent an attack by a nuclear weapon from another country by threatening nuclear retaliation is known as the strategy of nuclear deterrence. The goal in deterrence is to always maintain a second strike capability (the ability of a country to respond to a nuclear attack with one of its own) and potentially to strive for first strike status (the ability to completely destroy an enemy's nuclear forces before they could retaliate). During the Cold War, policy and military theorists in nuclear-enabled countries worked out models of what sorts of policies could prevent one from ever being attacked by a nuclear weapon.

Different forms of nuclear weapons delivery (see above) allow for different types of nuclear strategies. The goals of any strategy are generally to make it difficult for an enemy to launch a pre-emptive strike against the weapon system and difficult to defend against the delivery of the weapon during a potential conflict. Sometimes this has meant keeping the weapon locations hidden, such as deploying them on submarines or rail cars whose locations are very hard for an enemy to track and other times this means protecting them by burying them in hardened bunkers.

Other components of nuclear strategies have included using missile defense (to destroy the missiles before they land) or implementation of civil defense measures (using early-warning systems to evacuate citizens to safe areas before an attack).

Note that weapons which are designed to threaten large populations or to generally deter attacks are known as strategic weapons. Weapons which are designed to actually be used on a battlefield in military situations are known as tactical weapons.

There are critics of the very idea of nuclear strategy for waging nuclear war who have suggested that a nuclear war between two nuclear powers would result in mutual annihilation. From this point of view, the significance of nuclear weapons is purely to deter war because any nuclear war would immediately escalate out of mutual distrust and fear, resulting in mutually assured destruction. This threat of national, if not global, destruction has been a strong motivation for anti-nuclear weapons activism.

Critics from the peace movement and within the military establishment have questioned the usefulness of such weapons in the current military climate. According to an advisory opinion issued by the International Court of Justice in 1996, the use of (or threat of use of) such weapons would generally be contrary to the rules of international law applicable in armed conflict, but the court did not reach an opinion as to whether or not the threat or use would be lawful in specific extreme circumstances such as if the survival of the state were at stake.

Perhaps the most controversial idea in nuclear strategy is that nuclear proliferation would be desirable. This view argues that, unlike conventional weapons, nuclear weapons successfully deter all-out war between states, and they are said to have done this during the Cold War between the U.S. and the Soviet Union. Political scientist Kenneth Waltz is the most prominent advocate of this argument.

The threat of potentially suicidal terrorists possessing nuclear weapons (a form of nuclear terrorism) complicates the decision process. The prospect of mutually assured destruction may not deter an enemy who expects to die in the confrontation. Further, if the initial act is from a rogue group instead of a sovereign nation, there is no fixed nation or fixed military targets to retaliate against. It has been argued, especially after the September 11, 2001 attacks, that this complication is the sign of the next age of nuclear strategy, distinct from the relative stability of the Cold War. In 1996, the United States adopted a policy of allowing the targeting of its nuclear weapons at terrorists armed with weapons of mass destruction.

Governance, control, and law

Because of the immense military power they can confer, the political control of nuclear weapons has been a key issue for as long as they have existed; in most countries the use of nuclear force can only be authorized by the head of government or head of state.

In the late 1940s, lack of mutual trust was preventing the United States and the Soviet Union from making ground towards international arms control agreements, but by the 1960s steps were being taken to limit both the proliferation of nuclear weapons to other countries and the environmental effects of nuclear testing. The Partial Test Ban Treaty (1963) restricted all nuclear testing to underground nuclear testing, to prevent contamination from nuclear fallout, while the Nuclear Non-Proliferation Treaty (1968) attempted to place restrictions on the types of activities which signatories could participate in, with the goal of allowing the transference of non-military nuclear technology to member countries without fear of proliferation.

In 1957, the International Atomic Energy Agency (IAEA) was established under the mandate of the United Nations in order to encourage the development of the peaceful applications of nuclear technology, provide international safeguards against its misuse, and facilitate the application of safety measures in its use. In 1996, many nations signed the Comprehensive Test Ban Treaty which prohibits all testing of nuclear weapons, which would impose a significant hindrance to their development by any complying country. Due to the strict entry into force criterion of the convention however, it had as of 2011 not entered into force.

Additional treaties and agreements have governed nuclear weapons stockpiles between the countries with the two largest stockpiles, the United States and the Soviet Union, and later between the United States and Russia. These include treaties such as SALT II (never ratified), START I (expired), INF, START II (never ratified), SORT, and New START, as well as non-binding agreements such as SALT I and the Presidential Nuclear Initiatives of 1991. Even when they did not enter into force, these agreements helped limit and later reduce the numbers and types of nuclear weapons between the United States and the Soviet Union/Russia.

Nuclear weapons have also been opposed by agreements between countries. Many nations have been declared Nuclear-Weapon-Free Zones, areas where nuclear weapons production and deployment are prohibited, through the use of treaties. The Treaty of Tlatelolco (1967) prohibited any production or deployment of nuclear weapons in Latin America and the Caribbean, and the Treaty of Pelindaba (1964) prohibits nuclear weapons in many African countries. As recently as 2006 a Central Asian Nuclear Weapon Free Zone was established amongst the former Soviet republics of Central Asia prohibiting nuclear weapons.

In the middle of 1996, the International Court of Justice, the highest court of the United Nations, issued an Advisory Opinion concerned with the "Legality of the Threat or Use of Nuclear Weapons". The court ruled that the use or threat of use of nuclear weapons would violate various articles of international law, including the Geneva Conventions, the Hague Conventions, the UN Charter, and the Universal Declaration of Human Rights. In view of the unique, destructive characteristics of nuclear weapons, the International Committee of the Red Cross calls on States to ensure that these weapons are never used, irrespective of whether they consider them to be lawful or not.

Additionally, there have been other, specific actions meant to discourage countries from developing nuclear arms. In the wake of the tests by India and Pakistan in 1998, economic sanctions were (temporarily) levied against both countries, though neither were signatories with the Nuclear Non-Proliferation Treaty. One of the stated ''casus belli'' for the initiation of the 2003 Iraq War was an accusation by the United States that Iraq was actively pursuing nuclear arms (though this was soon discovered not to be the case as the program had been discontinued). In 1981, Israel had bombed a nuclear reactor being constructed in Osirak, Iraq, in what it called an attempt to halt Iraq's previous nuclear arms ambitions.

Disarmament

Nuclear disarmament refers to both the act of reducing or eliminating nuclear weapons and to the end state of a nuclear-free world, in which nuclear weapons are completely eliminated.

Beginning with the 1963 Partial Test Ban Treaty and continuing through the 1996 Comprehensive Test Ban Treaty, there have been many treaties to limit or reduce nuclear weapons testing and stockpiles. The 1968 Nuclear Non-Proliferation Treaty has as one of its explicit conditions that all signatories must "pursue negotiations in good faith" towards the long-term goal of "complete disarmament". However, no nuclear state has treated that aspect of the agreement as having binding force.

Only one country—South Africa—has ever fully renounced nuclear weapons they had independently developed. A number of former Soviet republics—Belarus, Kazakhstan, and Ukraine—returned Soviet nuclear arms stationed in their countries to Russia after the collapse of the USSR.

Proponents of nuclear disarmament say that it would lessen the probability of nuclear war occurring, especially accidentally. Critics of nuclear disarmament say that it would undermine deterrence and could lead to increased global instability. Various American government officials, who were in office during the Cold War period, have recently been advocating the elimination of nuclear weapons. These officials include Henry Kissinger, George Shultz, Sam Nunn, and William Perry. In January 2010, Lawrence M. Krauss stated that "no issue carries more importance to the long-term health and security of humanity than the effort to reduce, and perhaps one day, rid the world of nuclear weapons".

In the years after the end of the Cold War, there have been numerous campaigns to urge the abolition of nuclear weapons, such as that organized by the Global Zero movement, and the goal of a "world without nuclear weapons" was advocated by United States President Barack Obama in an April 2009 speech in Prague. A CNN poll from April 2010 indicated that the American public was nearly evenly split on the issue.

Controversy

Even before the first nuclear weapons had been developed, scientists involved with the Manhattan Project were divided over the use of the weapon. The role of the two atomic bombings of the country in Japan's surrender and the U.S.'s ethical justification for them has been the subject of scholarly and popular debate for decades. The question of whether nations should have nuclear weapons, or test them, has been continually and nearly universally controversial.

Radioactive fallout from nuclear weapons testing was first drawn to public attention in 1954 when the Castle Bravo hydrogen bomb test at the Pacific Proving Grounds contaminated the crew and catch of the Japanese fishing boat ''Lucky Dragon''. One of the fishermen died in Japan seven months later, and the fear of contaminated tuna led to a temporary boycotting of the popular staple in Japan. The incident caused widespread concern around the world, especially regarding the effects of nuclear fallout and atmospheric nuclear testing, and "provided a decisive impetus for the emergence of the anti-nuclear weapons movement in many countries".

Peace movements emerged in Japan and in 1954 they converged to form a unified "Japanese Council Against Atomic and Hydrogen Bombs". Japanese opposition to nuclear weapons tests in the Pacific Ocean was widespread, and "an estimated 35 million signatures were collected on petitions calling for bans on nuclear weapons".

In the United Kingdom, the first Aldermaston March organised by the Campaign for Nuclear Disarmament took place at Easter 1958, when several thousand people marched for four days from Trafalgar Square, London, to the Atomic Weapons Research Establishment close to Aldermaston in Berkshire, England, to demonstrate their opposition to nuclear weapons. The Aldermaston marches continued into the late 1960s when tens of thousands of people took part in the four-day marches.

In 1959, a letter in the ''Bulletin of Atomic Scientists'' was the start of a successful campaign to stop the Atomic Energy Commission dumping radioactive waste in the sea 19 kilometres from Boston. In 1962, Linus Pauling won the Nobel Peace Prize for his work to stop the atmospheric testing of nuclear weapons, and the "Ban the Bomb" movement spread.

In 1963, many countries ratified the Partial Test Ban Treaty prohibiting atmospheric nuclear testing. Radioactive fallout became less of an issue and the anti-nuclear weapons movement went into decline for some years. A resurgence of interest occurred amid European and American fears of nuclear war in the 1980s.

Between 1940 and 1996, the U.S. spent at least $}} in present day terms on nuclear weapons development. Over half was spent on building delivery mechanisms for the weapon. $}} in present day terms was spent on nuclear waste management and environmental remediation.

Non-weapons uses

Apart from their use as weapons, nuclear explosives have been tested and used for various non-military uses, and proposed, but not used for large-scale earth moving. When long term health and clean-up costs were included, there was no economic advantage over conventional explosives.

Synthetic elements, such as einsteinium and fermium, created by neutron bombardment of uranium and plutonium during thermonuclear explosions, were discovered in the aftermath of the first thermonuclear bomb test. In 2008 the worldwide presence of new isotopes from atmospheric testing beginning in the 1950s was developed into a reliable way of detecting art forgeries, as all paintings created after that period may contain traces of cesium-137 and strontium-90, isotopes that did not exist in nature before 1945.

Nuclear explosives have also been seriously studied as potential propulsion mechanisms for space travel (see Project Orion) and for asteroid deflection.

See also

Aftermath

Nuclear summer

Nuclear winter

History

History of nuclear weapons

*German nuclear energy project

*Japanese atomic program

*Manhattan Project

*Soviet atomic bomb project

Los Alamos National Laboratory

Lawrence Livermore National Laboratory

Lists of nuclear disasters and radioactive incidents

Nuclear and radiation accidents, including nuclear weapons accidents

Nuclear testing

*Nevada Test Site

*Project Gnome

Military strategy

*Civil Defense

*Fractional Orbital Bombardment System

*Mutual Assured Destruction

Weapon of mass destruction

*Nuclear strategy

*Nuclear warfare

More technical details

Effects of nuclear explosions

Intercontinental ballistic missile

Neutron bomb

Nuclear bombs and health

Nuclear weapon design

Nuclear weapon yield

Popular culture

Nuclear weapons in popular culture

The Butter Battle Book

Proliferation and politics

Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean

Comprehensive Test Ban Treaty

International Court of Justice advisory opinion on legality of nuclear weapons

List of states with nuclear weapons

List of nuclear weapons

Nth Country Experiment

Nuclear disarmament

Nuclear explosive

Nuclear Non-Proliferation Treaty

Nuclear peace

Nuclear proliferation

Nuclear weapons and the United Kingdom

The Letters of last resort (United Kingdom)

Nuclear weapons and Russia

Nuclear weapons and the United States

Paranuclear

Strategic Arms Limitation Talks

Three Non-Nuclear Principles, of Japan

References

Notes

Bibliography

Bethe, Hans Albrecht. ''The Road from Los Alamos''. New York: Simon and Schuster, 1991. ISBN 0-671-74012-1

DeVolpi, Alexander, Minkov, Vladimir E., Simonenko, Vadim A., and Stanford, George S. ''Nuclear Shadowboxing: Contemporary Threats from Cold War Weaponry''. Fidlar Doubleday, 2004 (Two volumes, both accessible on Google Book Search) (Content of both volumes is now available in the 2009 trilogy by Alexander DeVolpi: ''Nuclear Insights: The Cold War Legacy'' available on .

Glasstone, Samuel and Dolan, Philip J. ''The Effects of Nuclear Weapons (third edition).'' Washington, D.C.: U.S. Government Printing Office, 1977. Available online (PDF).

''NATO Handbook on the Medical Aspects of NBC Defensive Operations (Part I – Nuclear)''. Departments of the Army, Navy, and Air Force: Washington, D.C., 1996

Hansen, Chuck. ''U.S. Nuclear Weapons: The Secret History.'' Arlington, TX: Aerofax, 1988

Hansen, Chuck. ''The Swords of Armageddon: U.S. nuclear weapons development since 1945.'' Sunnyvale, CA: Chukelea Publications, 1995.

Holloway, David. ''Stalin and the Bomb''. New Haven: Yale University Press, 1994. ISBN 0-300-06056-4

The Manhattan Engineer District, "The Atomic Bombings of Hiroshima and Nagasaki" (1946)

Smyth, Henry DeWolf. ''Atomic Energy for Military Purposes.'' Princeton, NJ: Princeton University Press, 1945. (Smyth Report the first declassified report by the US government on nuclear weapons)

''The Effects of Nuclear War''. Office of Technology Assessment, May 1979.

Rhodes, Richard. ''Dark Sun: The Making of the Hydrogen Bomb''. New York: Simon and Schuster, 1995. ISBN 0-684-82414-0

Rhodes, Richard. ''The Making of the Atomic Bomb''. New York: Simon and Schuster, 1986 ISBN 0-684-81378-5

Weart, Spencer R. ''Nuclear Fear: A History of Images''. Cambridge, MA: Harvard University Press, 1988.

External links

Current World Nuclear Arsenals has estimates of nuclear arsenals in the respective countries.

General

Nuclear Weapon Archive from Carey Sublette is a reliable source of information and has links to other sources and an informative FAQ.

The Federation of American Scientists provide solid information on weapons of mass destruction, including nuclear weapons and their effects

Alsos Digital Library for Nuclear Issues—contains many resources related to nuclear weapons, including a historical and technical overview and searchable bibliography of web and print resources.

Everything you wanted to know about nuclear technology—Provided by ''New Scientist''.

Congressional Research Service (CRS) Reports regarding Nuclear weapons

Video archive of US, Soviet, UK, Chinese and French Nuclear Weapon Testing at sonicbomb.com

The National Museum of Nuclear Science & History (United States)—located in Albuquerque, New Mexico; a Smithsonian Affiliate Museum

Historical

The Manhattan Project: Making the Atomic Bomb at AtomicArchive.com

Los Alamos National Laboratory: History (U.S. nuclear history)

''Race for the Superbomb'', PBS website on the history of the H-bomb

U.S. nuclear test photographs from the DOE Nevada Site Office

U.S. nuclear test film clips from the DOE Nevada Site Office

Recordings of recollections of the victims of Hiroshima and Nagasaki

Category:American inventions Category:Articles containing video clips

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Arjun Makhijani is an electrical and nuclear engineer who is President of the Institute for Energy and Environmental Research. Makhijani has written many books and reports analyzing the safety, economics, and efficiency of various energy sources. He has testified before Congress and has served as an expert witness in Nuclear Regulatory Commission proceedings.

Professional experience

Arjun Makhijani is an electrical and nuclear engineer with 37 years experience in energy and nuclear issues. He is President of the Institute for Energy and Environmental Research. IEER has been doing nuclear-related studies for twenty years and is an independent non-profit organization located in Takoma Park, Maryland. Makhijani has a Ph.D. (Engineering), from the Department of Electrical Engineering and Computer Sciences of the University of California, Berkeley, where he specialized in the application of plasma physics to controlled nuclear fusion.

Makhijani has extensive professional experience and is qualified in radioactive waste disposal, standards for protection of human health from radiation, and the relative costs and benefits of nuclear energy and other energy sources. He has testified before Congress and has served as a consultant on energy issues to utilities and other organizations, including the Tennessee Valley Authority, the Lower Colorado River Authority, the Edison Electric Institute, the Lawrence Berkeley Laboratory, the Congressional Office of Technology Assessment, and several agencies of the United Nations. He has also served as an expert witness in Nuclear Regulatory Commission proceedings on nuclear facilities and in numerous lawsuits and has testified on a variety of issues including releases of radioactivity from nuclear facilities. He has testified before Congress on several occasions regarding issues related to nuclear waste, reprocessing, environmental releases of radioactivity, and regulation of nuclear weapons plants.

Makhijani has studied the French reprocessing and nuclear energy system and was the director of a team that analyzed ANDRA’s plans for a geological repository for high level radioactive waste in France on behalf of a French government-sponsored stakeholder committee (2004).

Publications

Arjun Makhijani has written a number of books and other publications analyzing the safety, economics, and efficiency of various energy sources, including nuclear power and renewable energy sources such as wind power and solar energy. He was the principal author of the first evaluation of energy end-uses and energy efficiency potential in the U.S. economy (published by the Electronics Research Laboratory, University of California at Berkeley in 1971). He was also the principal author of the first overview study on ''Energy and Agriculture in the Third World'' (Ballinger 1975). He was one of the principal technical staff of the Ford Foundation Energy Policy Project, and a co-author of its final report, ''A Time to Choose'', which helped shape U.S. energy policy during the mid-to-late 1970s. He is a co-author of ''Investment Planning in the Electricity Sector'', published by the Lawrence Berkeley Laboratory in 1976. He is also the principal author of ''Nuclear Power Deception'' (Apex Books 1999), an analysis of the costs of nuclear power in the United States and a co-author and principal editor of the first global assessment of the health and environmental effects of nuclear weapons production (''Nuclear Wastelands'', 1995 and 2000), which was nominated for a Pulitzer Prize by MIT Press. Most recently, Makhijani has authored ''Carbon-Free and Nuclear-Free'' (RDR Books and IEER Press 2007), the first analysis of a transition to a U.S. economy based completely on renewable energy, without any use of fossil fuels or nuclear power. He has many published articles in journals such as ''The Bulletin of the Atomic Scientists'' and ''The Progressive'', as well as in newspapers, including the ''Washington Post''. Arjun Makhijani has appeared on ABC World News Tonight, the CBS Evening News, CBS 60 Minutes, NPR, CNN, and BBC, among others.

Awards

In 1989, Dr Makhijani received The John Bartlow Martin Award for Public Interest Magazine Journalism of the Medill School of Journalism, Northwestern University, with Robert Alvarez; was awarded the Josephine Butler Nuclear Free Future Award in 2001; the 2007/2008 Jane Bagley Lehman Award for Excellence in Public Advocacy by the Tides Foundation; and was named a Ploughshares Hero, by the Ploughshares Fund (2006). In 2007, he was elected a Fellow of the American Physical Society.

See also

Anti-nuclear movement in the United States

References

External links

Nuclear isn’t necessary

Atomic Myths, Radioactive Realities

Category:Living people Category:American anti–nuclear power activists Category:American anti–nuclear weapons activists Category:American nuclear engineers Category:University of California, Berkeley alumni

Coordinates	21°40′11″N158°2′58″N
name	Bill Gates
birth date	October 28, 1955
birth place	Seattle, Washington, U.S.
birth name	William Henry Gates III
occupation	Chairman of MicrosoftChairman of CorbisCo-Chair of the Bill & Melinda Gates FoundationDirector of Berkshire HathawayCEO of Cascade Investment
years active	1975–present
nationality	American
net worth	US$56 billion (2011)
religion	Agnostic
spouse
children	3
residence	Medina, Washington, U.S.
alma mater	Harvard University (Dropout)
website	Bill Gates
signature	BillGates Signature.svg
parents	William H. Gates, Sr.Mary Maxwell Gates }}

William Henry "Bill" Gates III (born October 28, 1955) is an American business magnate, philanthropist, author and chairman of Microsoft, the software company he founded with Paul Allen. He is consistently ranked among the world's wealthiest people and was the wealthiest overall from 1995 to 2009, excluding 2008, when he was ranked third. During his career at Microsoft, Gates held the positions of CEO and chief software architect, and remains the largest individual shareholder, with more than 8 percent of the common stock. He has also authored or co-authored several books.

Gates is one of the best-known entrepreneurs of the personal computer revolution. Although he is admired by many, a number of industry insiders criticize his business tactics, which they consider anti-competitive, an opinion which has in some cases been upheld by the courts. In the later stages of his career, Gates has pursued a number of philanthropic endeavors, donating large amounts of money to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation, established in 2000.

Gates stepped down as chief executive officer of Microsoft in January 2000. He remained as chairman and created the position of chief software architect. In June 2006, Gates announced that he would be transitioning from full-time work at Microsoft to part-time work, and full-time work at the Bill & Melinda Gates Foundation. He gradually transferred his duties to Ray Ozzie, chief software architect, and Craig Mundie, chief research and strategy officer. Gates' last full-time day at Microsoft was June 27, 2008. He remains at Microsoft as non-executive chairman.

Early life

Gates was born in Seattle, Washington, to William H. Gates, Sr. and Mary Maxwell Gates, of English, German, and Scotch-Irish descent. His family was upper middle class; his father was a prominent lawyer, his mother served on the board of directors for First Interstate BancSystem and the United Way, and her father, J. W. Maxwell, was a national bank president. Gates has one elder sister, Kristi (Kristianne), and one younger sister, Libby. He was the fourth of his name in his family, but was known as William Gates III or "Trey" because his father had the "II" suffix. Early on in his life, Gates' parents had a law career in mind for him. When Gates was young, his family regularly attended a Congregational church.

At 13 he enrolled in the Lakeside School, an exclusive preparatory school. When he was in the eighth grade, the Mothers Club at the school used proceeds from Lakeside School's rummage sale to buy an Teletype Model 33 ASR terminal and a block of computer time on a General Electric (GE) computer for the school's students. Gates took an interest in programming the GE system in BASIC, and was excused from math classes to pursue his interest. He wrote his first computer program on this machine: an implementation of tic-tac-toe that allowed users to play games against the computer. Gates was fascinated by the machine and how it would always execute software code perfectly. When he reflected back on that moment, he said, "There was just something neat about the machine." After the Mothers Club donation was exhausted, he and other students sought time on systems including DEC PDP minicomputers. One of these systems was a PDP-10 belonging to Computer Center Corporation (CCC), which banned four Lakeside students—Gates, Paul Allen, Ric Weiland, and Kent Evans—for the summer after it caught them exploiting bugs in the operating system to obtain free computer time.

At the end of the ban, the four students offered to find bugs in CCC's software in exchange for computer time. Rather than use the system via Teletype, Gates went to CCC's offices and studied source code for various programs that ran on the system, including programs in FORTRAN, LISP, and machine language. The arrangement with CCC continued until 1970, when the company went out of business. The following year, Information Sciences, Inc. hired the four Lakeside students to write a payroll program in COBOL, providing them computer time and royalties. After his administrators became aware of his programming abilities, Gates wrote the school's computer program to schedule students in classes. He modified the code so that he was placed in classes with mostly female students. He later stated that "it was hard to tear myself away from a machine at which I could so unambiguously demonstrate success." At age 17, Gates formed a venture with Allen, called Traf-O-Data, to make traffic counters based on the Intel 8008 processor. In early 1973, Bill Gates served as a congressional page in the U.S. House of Representatives.

Gates graduated from Lakeside School in 1973. He scored 1590 out of 1600 on the SAT and enrolled at Harvard College in the autumn of 1973. While at Harvard, he met Steve Ballmer, who later succeeded Gates as CEO of Microsoft.

In his sophomore year, Gates devised an algorithm for pancake sorting as a solution to one of a series of unsolved problems presented in a combinatorics class by Harry Lewis, one of his professors. Gates' solution held the record as the fastest version for over thirty years; its successor is faster by only one percent. His solution was later formalized in a published paper in collaboration with Harvard computer scientist Christos Papadimitriou.

Gates did not have a definite study plan while a student at Harvard and spent a lot of time using the school's computers. Gates remained in contact with Paul Allen, joining him at Honeywell during the summer of 1974. The following year saw the release of the MITS Altair 8800 based on the Intel 8080 CPU, and Gates and Allen saw this as the opportunity to start their own computer software company. He had talked this decision over with his parents, who were supportive of him after seeing how much Gates wanted to start a company.

Microsoft

BASIC

After reading the January 1975 issue of ''Popular Electronics'' that demonstrated the Altair 8800, Gates contacted Micro Instrumentation and Telemetry Systems (MITS), the creators of the new microcomputer, to inform them that he and others were working on a BASIC interpreter for the platform. In reality, Gates and Allen did not have an Altair and had not written code for it; they merely wanted to gauge MITS's interest. MITS president Ed Roberts agreed to meet them for a demo, and over the course of a few weeks they developed an Altair emulator that ran on a minicomputer, and then the BASIC interpreter. The demonstration, held at MITS's offices in Albuquerque, was a success and resulted in a deal with MITS to distribute the interpreter as Altair BASIC. Paul Allen was hired into MITS, and Gates took a leave of absence from Harvard to work with Allen at MITS in Albuquerque in November 1975. They named their partnership "Micro-Soft" and had their first office located in Albuquerque. Within a year, the hyphen was dropped, and on November 26, 1976, the trade name "Microsoft" was registered with the Office of the Secretary of the State of New Mexico. Gates never returned to Harvard to complete his studies.

Microsoft's BASIC was popular with computer hobbyists, but Gates discovered that a pre-market copy had leaked into the community and was being widely copied and distributed. In February 1976, Gates wrote an Open Letter to Hobbyists in the MITS newsletter saying that MITS could not continue to produce, distribute, and maintain high-quality software without payment. This letter was unpopular with many computer hobbyists, but Gates persisted in his belief that software developers should be able to demand payment. Microsoft became independent of MITS in late 1976, and it continued to develop programming language software for various systems. The company moved from Albuquerque to its new home in Bellevue, Washington on January 1, 1979.

During Microsoft's early years, all employees had broad responsibility for the company's business. Gates oversaw the business details, but continued to write code as well. In the first five years, Gates personally reviewed every line of code the company shipped, and often rewrote parts of it as he saw fit.

IBM partnership

In 1980, IBM approached Microsoft to write the BASIC interpreter for its upcoming personal computer, the IBM PC. When IBM's representatives mentioned that they needed an operating system, Gates referred them to Digital Research (DRI), makers of the widely used CP/M operating system. IBM's discussions with Digital Research went poorly, and they did not reach a licensing agreement. IBM representative Jack Sams mentioned the licensing difficulties during a subsequent meeting with Gates and told him to get an acceptable operating system. A few weeks later Gates proposed using 86-DOS (QDOS), an operating system similar to CP/M that Tim Paterson of Seattle Computer Products (SCP) had made for hardware similar to the PC. Microsoft made a deal with SCP to become the exclusive licensing agent, and later the full owner, of 86-DOS. After adapting the operating system for the PC, Microsoft delivered it to IBM as PC-DOS in exchange for a one-time fee of $50,000. Gates did not offer to transfer the copyright on the operating system, because he believed that other hardware vendors would clone IBM's system. They did, and the sales of MS-DOS made Microsoft a major player in the industry.

Gates oversaw Microsoft's company restructuring on June 25, 1981, which re-incorporated the company in Washington state and made Gates President of Microsoft and the Chairman of the Board.

Windows

Microsoft launched its first retail version of Microsoft Windows on November 20, 1985, and in August, the company struck a deal with IBM to develop a separate operating system called OS/2. Although the two companies successfully developed the first version of the new system, mounting creative differences undermined the partnership. Gates distributed an internal memo on May 16, 1991, announcing that the OS/2 partnership was over and Microsoft would shift its efforts to the Windows NT kernel development.

Management style

From Microsoft's founding in 1975 until 2006, Gates had primary responsibility for the company's product strategy. He aggressively broadened the company's range of products, and wherever Microsoft achieved a dominant position he vigorously defended it. He gained a reputation for being distant to others; as early as 1981 an industry executive complained in public that "Gates is notorious for not being reachable by phone and for not returning phone calls."

As an executive, Gates met regularly with Microsoft's senior managers and program managers. Firsthand accounts of these meetings describe him as verbally combative, berating managers for perceived holes in their business strategies or proposals that placed the company's long-term interests at risk. He often interrupted presentations with such comments as, "That's the stupidest thing I've ever heard!" and, "Why don't you just give up your options and join the Peace Corps?" The target of his outburst then had to defend the proposal in detail until, hopefully, Gates was fully convinced. When subordinates appeared to be procrastinating, he was known to remark sarcastically, "I'll do it over the weekend."

Gates' role at Microsoft for most of its history was primarily a management and executive role. However, he was an active software developer in the early years, particularly on the company's programming language products. He has not officially been on a development team since working on the TRS-80 Model 100, but wrote code as late as 1989 that shipped in the company's products. On June 15, 2006, Gates announced that he would transition out of his day-to-day role over the next two years to dedicate more time to philanthropy. He divided his responsibilities between two successors, placing Ray Ozzie in charge of day-to-day management and Craig Mundie in charge of long-term product strategy.

Antitrust litigation

Many decisions that led to antitrust litigation over Microsoft's business practices have had Gates' approval. In the 1998 ''United States v. Microsoft'' case, Gates gave deposition testimony that several journalists characterized as evasive. He argued with examiner David Boies over the contextual meaning of words like "compete", "concerned" and "we". ''BusinessWeek'' reported:

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Gates later said he had simply resisted attempts by Boies to mischaracterize his words and actions. As to his demeanor during the deposition, he said, "Did I fence with Boies? ... I plead guilty. Whatever that penalty is should be levied against me: rudeness to Boies in the first degree." Despite Gates's denials, the judge ruled that Microsoft had committed monopolization and tying, and blocking competition, both in violation of the Sherman Antitrust Act.

Appearance in ads

Gates appeared in a series of ads to promote Microsoft in 2008. The first commercial, co-starring Jerry Seinfeld, is a 90-second talk between strangers as Seinfeld walks up on a discount shoe store (Shoe Circus) in a mall and notices Gates buying shoes inside. The salesman is trying to sell Mr. Gates shoes that are a size too big. As Gates is buying the shoes, he holds up his discount card, which uses a slightly altered version of his own mugshot of his arrest in New Mexico in 1977 for a traffic violation. As they are walking out of the mall, Seinfeld asks Gates if he has melded his mind to other developers, after getting a yes, he then asks if they are working on a way to make computers edible, again getting a yes. Some say that this is an homage to Seinfeld's own show about "nothing" (''Seinfeld''). In a second commercial in the series, Gates and Seinfeld are at the home of an average family trying to fit in with normal people.

Post-Microsoft

Since leaving Microsoft, Gates continues his philanthropy and, among other projects, purchased the video rights to the Messenger Lectures series called ''The Character of Physical Law'', given at Cornell University by Richard Feynman in 1964 and recorded by the BBC. The videos are available online to the public at Microsoft's Project Tuva.

In April 2010, Gates was invited to visit and speak at the Massachusetts Institute of Technology where he asked the students to take on the hard problems of the world in their futures.

Personal life

Gates married Melinda French on January 1, 1994. They have three children: daughter Jennifer Katharine Gates (born 1996), son Rory John Gates (born 1999), and daughter Phoebe Adele Gates (born 2002). The Gates's home is an earth-sheltered house in the side of a hill overlooking Lake Washington in Medina. According to King County public records, as of 2006 the total assessed value of the property (land and house) is $125 million, and the annual property tax is $991,000.

His estate has a swimming pool with an underwater music system, as well as a gym and a dining room.

Also among Gates' private acquisitions is the Codex Leicester, a collection of writings by Leonardo da Vinci, which Gates bought for $30.8 million at an auction in 1994. Gates is also known as an avid reader, and the ceiling of his large home library is engraved with a quotation from ''The Great Gatsby''. He also enjoys playing bridge, tennis, and golf.

Gates was number one on the Forbes 400 list from 1993 through to 2007 and number one on ''Forbes'' list of The World's Richest People from 1995 to 2007 and 2009. In 1999, Gates's wealth briefly surpassed $101 billion, causing the media to call him a "centibillionaire". Since 2000, the nominal value of his Microsoft holdings has declined due to a fall in Microsoft's stock price after the dot-com bubble burst and the multi-billion dollar donations he has made to his charitable foundations. In a May 2006 interview, Gates commented that he wished that he were not the richest man in the world because he disliked the attention it brought. Gates has several investments outside Microsoft, which in 2006 paid him a salary of $616,667 and $350,000 bonus totalling $966,667. He founded Corbis, a digital imaging company, in 1989. In 2004 he became a director of Berkshire Hathaway, the investment company headed by long-time friend Warren Buffett. In March 2010 Bill Gates was bumped down to the second wealthiest man behind Carlos Slim.

Philanthropy

Gates began to appreciate the expectations others had of him when public opinion mounted suggesting that he could give more of his wealth to charity. Gates studied the work of Andrew Carnegie and John D. Rockefeller, and in 1994 sold some of his Microsoft stock to create the William H. Gates Foundation. In 2000, Gates and his wife combined three family foundations into one to create the charitable Bill & Melinda Gates Foundation, which is the largest transparently operated charitable foundation in the world. The foundation allows benefactors access to information regarding how its money is being spent, unlike other major charitable organizations such as the Wellcome Trust. The generosity and extensive philanthropy of David Rockefeller has been credited as a major influence. Gates and his father met with Rockefeller several times, and modeled their giving in part on the Rockefeller family's philanthropic focus, namely those global problems that are ignored by governments and other organizations. As of 2007, Bill and Melinda Gates were the second-most generous philanthropists in America, having given over $28 billion to charity.

The foundation was at the same time criticized because it invests assets that it has not yet distributed with the exclusive goal of maximizing return on investment. As a result, its investments include companies that have been charged with worsening poverty in the same developing countries where the Foundation is attempting to relieve poverty. These include companies that pollute heavily, and pharmaceutical companies that do not sell into the developing world. In response to press criticism, the foundation announced in 2007 a review of its investments, to assess social responsibility. It subsequently canceled the review and stood by its policy of investing for maximum return, while using voting rights to influence company practices.

Gates's wife urged people to learn a lesson from the philanthropic efforts of the Salwen family, which had sold its home and given away half of its value, as detailed in ''The Power of Half''. Gates and his wife invited Joan Salwen to Seattle to speak about what the family had done, and on December 9, 2010, Gates, investor Warren Buffett, and Mark Zuckerberg (Facebook's CEO) signed a promise they called the "Gates-Buffet Giving Pledge", in which they promised to donate to charity at least half of their wealth over the course of time.

Recognition

In 1987, Gates was officially declared a billionaire in the pages of Forbes' 400 Richest People in America issue, just days before his 32nd birthday. As the world's youngest self-made billionaire, he was worth $1.25 billion, over $900 million more than he'd been worth the year before, when he'd debuted on the list.

''Time'' magazine named Gates one of the 100 people who most influenced the 20th century, as well as one of the 100 most influential people of 2004, 2005, and 2006. ''Time'' also collectively named Gates, his wife Melinda and U2's lead singer Bono as the 2005 Persons of the Year for their humanitarian efforts. In 2006, he was voted eighth in the list of "Heroes of our time". Gates was listed in the ''Sunday Times'' power list in 1999, named CEO of the year by ''Chief Executive Officers magazine'' in 1994, ranked number one in the "Top 50 Cyber Elite" by ''Time'' in 1998, ranked number two in the ''Upside'' Elite 100 in 1999 and was included in ''The Guardian'' as one of the "Top 100 influential people in media" in 2001.

In 1994, he was honoured as the twentieth Distinguished Fellow of the British Computer Society. Gates has received honorary doctorates from Nyenrode Business Universiteit, Breukelen, The Netherlands, in 2000; the Royal Institute of Technology, Stockholm, Sweden, in 2002; Waseda University, Tokyo, Japan, in 2005; Tsinghua University, Beijing, China, in April 2007; Harvard University in June 2007; the Karolinska Institutet, Stockholm, in January 2008, and Cambridge University in June 2009. He was also made an honorary trustee of Peking University in 2007. Gates was also made an honorary Knight Commander of the Order of the British Empire (KBE) by Queen Elizabeth II in 2005, in addition to having entomologists name the Bill Gates flower fly, ''Eristalis gatesi'', in his honor.

In November 2006, he and his wife were awarded the Order of the Aztec Eagle for their philanthropic work around the world in the areas of health and education, particularly in Mexico, and specifically in the program "''Un país de lectores"''. In October 2009, it was announced that Gates will be awarded the 2010 Bower Award for Business Leadership of The Franklin Institute for his achievements in business and for his philanthropic work. In 2010 he was honored with the Silver Buffalo Award by the Boy Scouts of America, its highest award for adults, for his service to youth.

Investments

Cascade Investments LLC, a private investment and holding company, incorporated in United States, is controlled by Bill Gates, and is headquartered in the city of Kirkland, Washington.

bgC3, a new think-tank company founded by Bill Gates.

Corbis, a digital image licensing and rights services company.

TerraPower, a nuclear reactor design company.

Bibliography

Gates has authored two books:

''The Road Ahead'' (1995)

''Business @ the Speed of Thought'' (1999)

Filmography

Gates has appeared in at least one film: ''Waiting For Superman''

See also

List of billionaires (also see List of college dropout billionaires and List of wealthiest non-inflated historical figures)

Paul Allen – Microsoft's co-founder, friend, and fellow billionaire

Books

References

Further reading

"The Meaning of Bill Gates: As his reign at Microsoft comes to an end, so does the era he dominated", ''The Economist'', June 28, 2008.

External links

The Gates Notes ''official site''

Bill & Melinda Gates Foundation

Profile at Microsoft

Profile at Forbes

How I Work: Bill Gates, ''Fortune'', March 30, 2006

Category:1955 births Category:American billionaires Category:American computer businesspeople Category:American chief executives Category:American computer programmers Category:American philanthropists Category:American technology writers Category:Bill & Melinda Gates Foundation people Category:Businesspeople in software Category:Harvard University people Category:Honorary Knights Commander of the Order of the British Empire Category:Members of the United States National Academy of Engineering Category:Microsoft employees Category:History of Microsoft Category:National Medal of Technology recipients Category:Living people Category:People from Seattle, Washington Category:People from King County, Washington Category:Windows people Category:Fellows of the British Computer Society Category:American people of Scottish descent

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