Thermonuclear weapon
A thermonuclear weapon, or fusion weapon, is a second-generation nuclear weapon design which affords vastly greater destructive power than first-generation atomic bombs. Modern fusion weapons consist of two main components: a nuclear fission primary stage and a separate nuclear fusion secondary stage containing thermonuclear fuel: the heavy hydrogen isotopes deuterium and tritium, or in modern weapons lithium deuteride. For this reason, thermonuclear weapons are colloquially called hydrogen bombs or H-bombs. A fusion explosion begins with the detonation of the fission primary stage, its temperature soars past one hundred million Kelvins, causing it to glow intensely with thermal x-radiation. These X-rays flood the void between the primary and secondary assemblies placed within an enclosure called a radiation case, which confines the X-ray energy and resists getting pressed outwards; the distance separating the two assemblies ensures that debris fragments from the fission primary cannot disassemble the secondary before the fusion explosion runs to completion.
The secondary fusion stage—consisting of pusher/tamper, fusion fuel, plutonium spark plug—is imploded by the X-ray energy pressing it inward. This drives up the density of the plutonium spark plug at its center; the density of the plutonium fuel rises to such an extent that the spark plug is driven into a supercritical state, it begins a nuclear fission chain reaction. The fission products so produced heat the compressed, thus superdense, thermonuclear fuel surrounding the spark plug to the region of some three hundred million Kelvins, igniting fusion reactions between fusion fuel nuclei. In modern weapons fueled by lithium deuteride, the fissioning plutonium spark plug emits free neutrons which collide with lithium nuclei and supply the tritium component of the thermonuclear fuel; the radiation implosion mechanism exploits the temperature difference between the secondary stage's hot, surrounding radiation channel and its cool interior. This temperature difference is maintained by a massive heat barrier called the "pusher"/"tamper", which serves as an implosion tamper and prolonging the compression of the secondary.
If made of uranium, enriched uranium or plutonium, it can capture fusion neutrons produced by the fusion reaction and undergo fission itself, increasing the overall explosive yield. In addition to that, some designs make the radiation case out of a fissile material that undergoes fission; as a result, such bombs get a third tertiary fission stage, the majority of current Teller–Ulam are fission-fusion-fission weapons. Fission of the tamper or radiation case is the main contribution to the total yield and produces radioactive fission product fallout; the first full-scale thermonuclear test was carried out by the United States in 1952. The design of all modern thermonuclear weapons in the United States is known as the Teller–Ulam configuration for its two chief contributors, Edward Teller and Stanislaw Ulam, who developed it in 1951 for the United States, with certain concepts developed with the contribution of physicist John von Neumann. Similar devices were developed by the Soviet Union, United Kingdom and China.
As thermonuclear weapons represent the most efficient design for weapon energy yield in weapons with yields above 50 kilotons of TNT all the nuclear weapons of this size deployed by the five nuclear-weapon states under the Non-Proliferation Treaty today are thermonuclear weapons using the Teller–Ulam design. Detailed knowledge of fission and fusion weapons is classified to some degree in every industrialized nation. In the United States, such knowledge can by default be classified as "Restricted Data" if it is created by persons who are not government employees or associated with weapons programs, in a legal doctrine known as "born secret". Born secret is invoked for cases of private speculation; the official policy of the United States Department of Energy has been not to acknowledge the leaking of design information, as such acknowledgment would validate the information as accurate. In a small number of prior cases, the U. S. government has attempted to censor weapons information in the public press, with limited success.
According to the New York Times, physicist Kenneth W. Ford defied government orders to remove classified information from his book, Building the H Bomb: A Personal History. Ford claims he used only pre-existing information and submitted a manuscript to the government, which wanted to remove entire sections of the book for concern that foreign nations could use the information. Though large quantities of vague data have been released, larger quantities of vague data have been unofficially leaked by former bomb designers, most public descriptions of nuclear weapon design details rely to some degree on speculation, reverse engineering from known information, or comparison with similar fields of physics; such processes have resulted in a body of unclassified knowledge about nuclear bombs, consistent with official unclassified information releases, related physics, is thought to be internally consistent, though there are some points of interpretation that are still considered open. The state of public knowledge about the Teller–Ulam design has been mos
Nuclear ethics
Nuclear ethics is a cross-disciplinary field of academic and policy-relevant study in which the problems associated with nuclear warfare, nuclear deterrence, nuclear arms control, nuclear disarmament, or nuclear energy are examined through one or more ethical or moral theories or frameworks. In contemporary security studies, the problems of nuclear warfare, proliferation, so forth are understood in political, strategic, or military terms. In the study of international organizations and law, these problems are understood in legal terms. Nuclear ethics assumes that the real possibilities of human extinction, mass human destruction, or mass environmental damage which could result from nuclear warfare are deep ethical or moral problems, it assumes that the outcomes of human extinction, mass human destruction, or environmental damage count as moral evils. Another area of inquiry concerns future generations and the burden that nuclear waste and pollution imposes on them; some scholars have concluded that it is therefore morally wrong to act in ways that produce these outcomes, which means it is morally wrong to engage in nuclear warfare.
Nuclear ethics is interested in examining policies of nuclear deterrence, nuclear arms control and disarmament, nuclear energy insofar as they are linked to the cause or prevention of nuclear warfare. Ethical justifications of nuclear deterrence, for example, emphasize its role in preventing great power nuclear war since the end of World War II. Indeed, some scholars claim that nuclear deterrence seems to be the morally rational response to a nuclear-armed world. Moral condemnation of nuclear deterrence, in contrast, emphasizes the inevitable violations of human and democratic rights which arise; the application of nuclear technology, both as a source of energy and as an instrument of war, has been controversial. 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. The public became concerned about nuclear weapons testing from about 1954, following extensive nuclear testing in the Pacific Ocean. In 1961, at the height of the Cold War, about 50,000 women brought together by Women Strike for Peace marched in 60 cities in the United States to demonstrate against nuclear weapons. In 1963, many countries ratified the Partial Test Ban Treaty which prohibited atmospheric nuclear testing; some local opposition to nuclear power emerged in the early 1960s, in the late 1960s some members of the scientific community began to express their concerns. In the early 1970s, there were large protests about a proposed nuclear power plant in Germany; the project was cancelled in 1975 and anti-nuclear success at Wyhl inspired opposition to nuclear power in other parts of Europe and North America. Nuclear power became an issue of major public protest in the 1970s.
Between 1949 and 1989, over 4,000 uranium mines in the Four Corner region of the American Southwest produced more than 225,000,000 tons of uranium ore. This activity affected a large number of Native American nations, including the Laguna, Zuni, Southern Ute, Ute Mountain, Hopi and other Pueblo cultures. Many of these peoples worked in the mines and processing plants in New Mexico, Arizona and Colorado; these workers were not only poorly paid, they were informed of dangers nor were they given appropriate protective gear. The government, mine owners and health communities were all well aware of the hazards of working with radioactive materials at this time. Due to the Cold War demand for destructive and powerful nuclear weapons, these laborers were both exposed to and brought home large amounts of radiation in the form of dust on their clothing and skin. Epidemiologic studies of the families of these workers have shown increased incidents of radiation-induced cancers, cleft palates and other birth defects.
The extent of these genetic effects on indigenous populations and the extent of DNA damage remains to be resolved. Uranium mining on the Navajo reservation continues to be a disputed issue as former Navajo mine workers and their families continue to suffer from health problems. February 13, 1950: a Convair B-36B crashed in northern British Columbia after jettisoning a Mark IV atomic bomb; this was the first such nuclear weapon loss in history. May 22, 1957: a 42,000-pound Mark-17 hydrogen bomb accidentally fell from a bomber near Albuquerque, New Mexico; the detonation of the device's conventional explosives destroyed it on impact and formed a crater 25-feet in diameter on land owned by the University of New Mexico. According to a researcher at the Natural Resources Defense Council, it was one of the most powerful bombs made to date. 7 June 1960: the 1960 Fort Dix IM-99 accident destroyed a Boeing CIM-10 Bomarc nuclear missile and shelter and contaminated the BOMARC Missile Accident Site in New Jersey.
24 January 1961: the 1961 Goldsboro B-52 crash occurred near Goldsboro, North Carolina. A B-52 Stratofortress carrying two Mark 39 nuclear bombs broke up in mid-air, dropping its nuclear payload in the process. 1965 Philippine Sea A-4 crash, where a Skyhawk attack aircraft with a nuclear weapon fell into the sea. The pilot, the aircraft, the B43 nuclear bomb were never recovered, it was not until the 1980s. January 17, 1966: the 1966 Palomares B-52 crash occurred when a B-52G bomber of the USAF col
High-altitude nuclear explosion
High-altitude nuclear explosions are the result of nuclear weapons testing. Several such tests were performed at high altitudes by the United States and the Soviet Union between 1958 and 1962; the strong electromagnetic pulse that results has several components. In the first few tenths of nanoseconds, about a tenth of a percent of the weapon yield appears as powerful gamma rays with energies of one to three mega-electron volts; the gamma rays penetrate the atmosphere and collide with air molecules, depositing their energy to produce huge quantities of positive ions and recoil electrons. The impacts create MeV-energy Compton electrons that accelerate and spiral along the Earth's magnetic field lines; the resulting transient electric fields and currents that arise generate electromagnetic emissions in the radio frequency range of 15 to 250 megahertz. This high-altitude EMP occurs between 50 kilometers above the Earth's surface; the potential as an anti-satellite weapon became apparent in August 1958 during Hardtack Teak.
The EMP observed at the Apia Observatory at Samoa was four times more powerful than any created by solar storms, while in July 1962 the Starfish Prime test, damaged electronics in Honolulu and New Zealand, fused 300 street lights on Oahu, set off about 100 burglar alarms, caused the failure of a microwave repeating station on Kauai, which cut off the sturdy telephone system from the other Hawaiian islands. The radius for an effective satellite kill for the various Compton radiation produced by such a nuclear weapon in space was determined to be 80 km. Further testing to this end was carried out, embodied in a Department of Defense program, Program 437. There are problems with nuclear weapons carried over to deployment scenarios, however; because of the large radius associated with nuclear events, it was nearly impossible to prevent indiscriminate damage to other satellites, including one's own satellites. Starfish Prime produced an artificial radiation belt in space; the radiation dose rate was at least 60 rads/day at four months after Starfish for a well-shielded satellite or manned capsule in a polar circular earth orbit, which caused NASA concern with regard to its manned space exploration programs.
In general, nuclear effects in space have a qualitatively different display. While an atmospheric nuclear explosion has a characteristic mushroom-shaped cloud, high-altitude and space explosions tend to manifest a spherical'cloud,' reminiscent of other space-based explosions until distorted by Earth's magnetic field, the charged particles resulting from the blast can cross hemispheres to create an auroral display which has led documentary maker Peter Kuran to characterize these detonations as'the rainbow bombs'; the visual effects of a high-altitude or space-based explosion may last longer than atmospheric tests, sometimes in excess of 30 minutes. Heat from the Bluegill Triple Prime shot, at an altitude of 50 kilometers, was felt by personnel on the ground at Johnston Atoll, this test caused retina burns to two personnel at ground zero who were not wearing their safety goggles; the Soviets detonated four high-altitude tests in 1961 and three in 1962. During the Cuban Missile Crisis in October 1962, both the US and the USSR detonated several high-altitude nuclear explosions as a form of saber rattling.
The worst effects of a Soviet high-altitude test occurred on 22 October 1962, in the Soviet Project K nuclear tests when a 300 kt missile-warhead detonated near Dzhezkazgan at 290-km altitude. The EMP fused 570 km of overhead telephone line with a measured current of 2,500 A, started a fire that burned down the Karaganda power plant, shut down 1,000-km of shallow-buried power cables between Tselinograd and Alma-Ata; the Partial Test Ban Treaty was passed the following year, ending atmospheric and exoatmospheric nuclear tests. The Outer Space Treaty of 1967 banned the use of nuclear weapons in space; the Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all kinds of nuclear explosions. Operation Argus Operation Fishbowl Outer Space Treaty Partial Test Ban Treaty Project Highwater Soviet Project K nuclear tests The Yekaterinburg Fireball is suspected by some of being a high altitude nuclear explosion "High-altitude nuclear explosions" Peter Kuran's Nukes in Space: The Rainbow Bombs – documentary film from 1999 United States high-altitude test experiences – A Review Emphasizing the Impact on the Environment Measured EMP waveform data and actual effects from high-altitude nuclear weapons tests by America and Russia American and British official analyses of photography from high-altitude nuclear explosionsUS Government Films: Operation Argus Operation Dominic Starfish Prime Operation Fishbowl Operation Dominic – Christmas Island Operation Dominic – Johnston Island High-Altitude Effects – Phenomenology High-Altitude Effects – Systems Interference
Alpha Centauri
Alpha Centauri is the closest star system and closest planetary system to the Solar System at 4.37 light-years from the Sun. It is a triple star system, consisting of three stars: α Centauri A, α Centauri B, α Centauri C. Alpha Centauri A and B are Sun-like stars, together they form the binary star Alpha Centauri AB. To the naked eye, the two main components appear to be a single star with an apparent magnitude of −0.27, forming the brightest star in the southern constellation of Centaurus and the third-brightest in the night sky, outshone only by Sirius and Canopus. Alpha Centauri A has 1.1 times the mass and 1.519 times the luminosity of the Sun, while Alpha Centauri B is smaller and cooler, at 0.907 times the Sun's mass and 0.445 times its luminosity. The pair orbit about a common centre with an orbital period of 79.91 years. Their elliptical orbit is eccentric, so that the distance between A and B varies from 35.6 astronomical units, or about the distance between Pluto and the Sun, to that between Saturn and the Sun.
Alpha Centauri C, or Proxima Centauri, is a faint red dwarf. Though not visible to the naked eye, Proxima Centauri is the closest star to the Sun at a distance of 4.24 light-years closer than Alpha Centauri AB. The distance between Proxima Centauri and Alpha Centauri AB is about 13,000 astronomical units, equivalent to about 430 times the radius of Neptune's orbit. Proxima Centauri b is an Earth-sized exoplanet in the habitable zone of Proxima Centauri. Α Centauri is the system's designation given by Johann Bayer in 1603. It once bore the name Rigil Kentaurus, a Latinisation of the Arabic name رجل القنطورس Rijl al-Qanṭūris, meaning'Foot of the Centaur'. Alpha Centauri C was discovered in 1915 by Robert T. A. Innes, who suggested that it be named Proxima Centaurus amended to Proxima Centauri; the name is from Latin, meaning'nearest of Centaurus'. In 2016, the Working Group on Star Names of the International Astronomical Union, having decided to attribute proper names to individual stars rather than entire multiple systems, approved the names Rigil Kentaurus for Alpha Centauri A and Proxima Centauri for Alpha Centauri C.
In 10 August 2018, IAU approved the name Toliman for Alpha Centauri B. Alpha Centauri is a triple star system, with its two main stars, Alpha Centauri A and Alpha Centauri B, being a binary component; the AB designation, or older A×B, denotes the mass centre of a main binary system relative to companion star in a multiple star system. AB-C refers to the component of Proxima Centauri in relation to the central binary, being the distance between the centre of mass and the outlying companion; because the distance between Proxima and either of Alpha Centauri A or B is similar, the AB binary system is sometimes treated as a single gravitational object. The A and B components of Alpha Centauri have an orbital period of 79.91 years. Their orbit is moderately eccentric, e = 0.5179. Viewed from Earth, the apparent orbit of A and B means that their separation and position angle are in continuous change throughout their projected orbit. Observed stellar positions in 2019 are separated by 4.92 arcsec through the PA of 337.1°, increasing to 5.49 arcsec through 345.3° in 2020.
The closest recent approach was in February 2016, at 4.0 arcsec through the PA of 300°. The observed maximum separation of these stars is about 22 arcsec, while the minimum distance is 1.7 arcsec. The widest separation occurred during February 1976, the next will be in January 2056; the most recent, true orbit, closest approach or periastron was in August 1955, the next will be in May 2035. The furthest orbital separation or apastron last occurred in May 1995, the next will be in 2075; the apparent distance between Alpha Centauri A and B is decreasing, at least until 2019. Alpha Centauri C is about 13,000 astronomical units away from Alpha Centauri AB; this is equivalent to 0.21 ly or 1.9 trillion km—about 5% the distance between Alpha Centauri AB and the Sun. For a long time, estimates of Proxima's small orbital speed around AB were insufficiently accurate to determine whether Proxima Centauri is bound to the Alpha Centauri system or an unrelated star that happens to be passing by at a low speed.
Radial velocity measurements made in 2017 were precise enough to show that Proxima Centauri and Alpha Centauri AB are gravitationally bound. The orbital period of Proxima Centauri is 547000+6600−4000 years, with an eccentricity of 0.50 ± 0.08, more eccentric than Mercury's. Proxima Centauri comes within 4300+1100−900 AU of AB at periastron, the apastron occurs at 13000+300−100 AU. Asteroseismic studies, chromospheric activity, stellar rotation are all consistent with the Alpha Centauri system being similar in age to, or older than, the Sun. Asteroseismic analyses that incorporate tight observational constraints on the stellar parameters for the Alpha Centauri stars have yielded age estimates of 4.85±0.5 Gyr, 5.0±0.5 Gyr, 5.2 ± 1.9 Gyr, 6.4 Gyr, 6.52±0.3 Gyr. Age estimates for the stars based on chromospheric activity yield 4.4 ± 2.1 Gyr, whereas gyrochronology yields 5.0±0.3 Gyr. Stellar evolution theory implies both stars are older than the Sun at 5 to 6 billion years, as derived by their mass and spectral characteristics.
From the orbital elements, th
Pulsed nuclear thermal rocket
A pulsed nuclear thermal rocket is a type of nuclear thermal rocket concept developed at the Polytechnic University of Catalonia and presented at the 2016 AIAA/SAE/ASEE Propulsion Conference for thrust and specific impulse amplification in a conventional nuclear thermal rocket. The pulsed nuclear thermal rocket is a bimodal rocket able to work in a stationary, as well as a pulsed mode as a TRIGA-like reactor, making possible the production of high power and an intensive neutron flux in short time intervals. In contrast to nuclear reactors where velocities of the coolant are no larger than a few meter per second and thus, typical residence time is on seconds, however, in rockets chambers with subsonic velocities of the propellant around hundreds of meters per second, residence time are around 10 − 2 s to: 10 − 3 s and a long power pulse translates into an important gain in energy in comparison with the stationary mode; the gained energy -by pulsing the nuclear core, can be used for thrust amplification by increasing the propellant mass flow, or using the intensive neutron flux to produce a high specific impulse amplification – higher than the fission-fragment rocket, where in the pulsed rocket the final propellant temperature is only limited by the radiative cooling after the pulsation.
A rough calculation for the energy gain by using a pulsed thermal nuclear rocket in comparison with the conventional stationary mode, is as follows. The energy stored into the fuel after a pulsation, is the sensible heat stored because the fuel temperature increase; this energy may be written as E pulse = c f M f Δ T where: E pulse is the sensible heat stored after pulsation, c f is the fuel heat capacity, M f is the fuel mass, Δ T is the temperature increase between pulsations. On the other hand, the energy generated in the stationary mode, i.e. when the nuclear core operates at nominal constant power is given by E stationary = χ l l t where: χ l is the linear power of the fuel, l is the length of the fuel, t is the residence time of the propellant in the chamber. For the case of cylindrical geometries for the nuclear fuel we have M f = π R f 2 l ρ l and the linear power given by χ l = 4 π κ f Where: R f is the radius of the cylindrical fuel, ρ f the fuel density, κ f the fuel thermal conductivity, T f is the fuel temperature at the center line, T s is the surface or cladding temperature.
Therefore, the energy ratio between the pulsed mode and the stationary mode, N = E pulse E stationary yields N = c f ρ f R f 2 4 π κ f Where the term inside the bracket, is the quenching rate. Typical average values of the parameters for common nuclear fuels as MOX fuel or uranium dioxide are: heat capacities, thermal conductivity and densities around c f ≃ 300 J /, κ f ≃ 6 W / and ρ f ≃ 10 4 k g /, respectively. With radius close to R f ≃ 10 − 2 m, the temperature drop between the center line and the cladding on T f − T
Nuclear fusion
In nuclear chemistry, nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles. The difference in mass between the reactants and products is manifested as either the release or absorption of energy; this difference in mass arises due to the difference in atomic "binding energy" between the atomic nuclei before and after the reaction. Fusion is other high magnitude stars. A fusion process that produces a nucleus lighter than iron-56 or nickel-62 will yield a net energy release; these elements have the smallest mass per nucleon and the largest binding energy per nucleon, respectively. Fusion of light elements toward these releases energy, while a fusion producing nuclei heavier than these elements will result in energy retained by the resulting nucleons, the resulting reaction is endothermic; the opposite is true for nuclear fission. This means that the lighter elements, such as helium, are in general more fusible.
The extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron. In 1920, Arthur Eddington suggested hydrogen-helium fusion could be the primary source of stellar energy. Quantum tunneling was discovered by Friedrich Hund in 1929, shortly afterwards Robert Atkinson and Fritz Houtermans used the measured masses of light elements to show that large amounts of energy could be released by fusing small nuclei. Building on the early experiments in nuclear transmutation by Ernest Rutherford, laboratory fusion of hydrogen isotopes was accomplished by Mark Oliphant in 1932. In the remainder of that decade, the theory of the main cycle of nuclear fusion in stars were worked out by Hans Bethe. Research into fusion for military purposes began in the early 1940s as part of the Manhattan Project. Fusion was accomplished in 1951 with the Greenhouse Item nuclear test. Nuclear fusion on a large scale in an explosion was first carried out on 1 November 1952, in the Ivy Mike hydrogen bomb test.
Research into developing controlled thermonuclear fusion for civil purposes began in earnest in the 1940s, it continues to this day. The release of energy with the fusion of light elements is due to the interplay of two opposing forces: the nuclear force, which combines together protons and neutrons, the Coulomb force, which causes protons to repel each other. Protons are positively charged and repel each other by the Coulomb force, but they can nonetheless stick together, demonstrating the existence of another, short-range, force referred to as nuclear attraction. Light nuclei are sufficiently small and proton-poor allowing the nuclear force to overcome repulsion; this is because the nucleus is sufficiently small that all nucleons feel the short-range attractive force at least as as they feel the infinite-range Coulomb repulsion. Building up nuclei from lighter nuclei by fusion releases the extra energy from the net attraction of particles. For larger nuclei, however, no energy is released, since the nuclear force is short-range and cannot continue to act across longer atomic length scales.
Thus, energy is not released with the fusion of such nuclei. Fusion powers stars and produces all elements in a process called nucleosynthesis; the Sun is a main-sequence star, and, as such, generates its energy by nuclear fusion of hydrogen nuclei into helium. In its core, the Sun fuses 620 million metric tons of hydrogen and makes 606 million metric tons of helium each second; the fusion of lighter elements in stars releases the mass that always accompanies it. For example, in the fusion of two hydrogen nuclei to form helium, 0.7% of the mass is carried away in the form of kinetic energy of an alpha particle or other forms of energy, such as electromagnetic radiation. It takes considerable energy to force nuclei to fuse those of the lightest element, hydrogen; when accelerated to high enough speeds, nuclei can overcome this electrostatic repulsion and brought close enough such that the attractive nuclear force is greater than the repulsive Coulomb force. The strong force grows once the nuclei are close enough, the fusing nucleons can "fall" into each other and the result is fusion and net energy produced.
The fusion of lighter nuclei, which creates a heavier nucleus and a free neutron or proton releases more energy than it takes to force the nuclei together. Energy released in most nuclear reactions is much larger than in chemical reactions, because the binding energy that holds a nucleus together is greater than the energy that holds electrons to a nucleus. For example, the ionization energy gained by adding an electron to a hydrogen nucleus is 13.6 eV—less than one-millionth of the 17.6 MeV released in the deuterium–tritium reaction shown in the adjacent diagram. The complete conversion of one gram of matter would release 9×1013 joules of energy. Fusion reactions have an energy density many times greater than nuclear fission. Only direct conversion of mass into energy, such as that caused by the annihilatory collision of matter and antimatter, is more energetic per unit of mass than nuclear fusion. Research into using fusion for the p
Deep Impact (film)
Deep Impact is a 1998 American science-fiction disaster film directed by Mimi Leder, written by Bruce Joel Rubin and Michael Tolkin, starring Robert Duvall, Téa Leoni, Elijah Wood, Vanessa Redgrave, Maximilian Schell, Morgan Freeman. Steven Spielberg served as an executive producer of this film, it was released by Paramount Pictures in the United States and by DreamWorks Pictures internationally on May 8, 1998. The film depicts the attempts to prepare for and destroy a 7-mile wide comet set to collide with Earth and cause a mass extinction. Deep Impact was released in the same summer as a themed film, which fared better at the box office, while astronomers described Deep Impact as being more scientifically accurate. Both films were received by critics, with Armageddon scoring 39% and Deep Impact scoring 44% on Rotten Tomatoes, with Deep Impact grossing over $349 million worldwide on an $80 million production budget, it was the final film by cinematographer Dietrich Lohmann. On May 10, 1998, teenaged amateur astronomer Leo Biederman discovers an unusual object near the stars Mizar and Alcor at a star party.
His teacher has Leo take a picture and sends it to astronomer Dr. Marcus Wolf. Wolf realizes. Wolf dies in a car accident on his way to try to alert the authorities. One year MSNBC journalist Jenny Lerner investigates the sudden resignation of Secretary of the Treasury Alan Rittenhouse and his connection to "Ellie" a mistress. After interviewing Rittenhouse, she is taken by the FBI to see President Tom Beck. After this, she finds out that Ellie is an acronym: "E. L. E.". Due to Lerner's investigation, President Beck makes an announcement earlier than planned: the comet, named Wolf-Biederman, is headed for Earth and it is 7 miles long, large enough to cause a mass extinction, wipe out humanity, he reveals that the United States and Russia have been constructing an Orion spacecraft called the Messiah in orbit that will transport a team, led by Mission Commander Oren Monash and including veteran astronaut Captain Spurgeon "Fish" Tanner, to the comet, hoping to alter its path with nuclear weapons. After landing on the comet, the crew plant nuclear bombs beneath the surface, but are caught in outgassing explosions when sunlight heats up the comet.
Monash is permanently blinded by unfiltered sunlight and suffers severe facial burns, while Dr. Gus Partenza is flung into space by an outflow of gas; when the bombs detonate, the ship is damaged by the blast and the team loses contact with Earth. President Beck announces that the bombs only split the comet into two smaller pieces, nicknamed "Biederman" and "Wolf", both still heading for Earth. Beck imposes martial law and reveals that governments worldwide have been building underground shelters; the United States' shelter is in the limestone caves of Missouri. A lottery selects 800,000 Americans under age 50 to join 200,000 selected individuals, as well as a massive supply of food, genetically viable populations of significant animals, the seeds of every plant species. Lerner and the Biederman family are chosen, but Leo's girlfriend Sarah Hotchner and her family are not. Leo marries Sarah to try to save her family. Sarah refuses to leave without her parents. A last-ditch effort to use ICBMs to deflect the comets fails.
Biederman will strike the Atlantic Ocean off Cape Hatteras and generate megatsunamis up to 3,500 ft high. Wolf will hit western Canada, creating a huge cloud of dust and molten particles that will block out the Sun for two years, killing all life on the surface in a matter of weeks. Leo returns home looking for Sarah, but her family has left for the Appalachian Mountains and are stuck in a massive traffic jam. Leo catches up to them on a motorcycle. Sarah's parents tell Leo to take her baby brother to high ground. Meanwhile, Lerner gives up her seat in the last evacuation helicopter to her friend Beth and Beth's young daughter, she joins her estranged father Jason at their family beach house. Biederman hits the water, creating a megatsunami that destroys the Eastern Seaboard of the United States. Lerner and Sarah's parents are among the thousands that are killed by the massive wave. Leo and her baby brother are able to reach the higher grounds of the Appalachian Mountains safely. Unable to safely attempt a second landing, the crew of Messiah decide to obliterate Wolf by undertaking a suicide mission.
After they say goodbye to their loved ones by video conference, they fly directly into a large deep crevasse created by out-gassing, use their remaining nuclear warheads to blow Wolf into smaller pieces that burn up harmlessly in Earth's atmosphere. After the waters recede, President Beck speaks to a large crowd at the US Capitol, being rebuilt, encouraging them to remember and honor the heroes for their sacrifice; the origins of Deep Impact started in the late 1970s when producers Richard Zanuck and David Brown approached Paramount Studios proposing a remake of the 1951 film When Worlds Collide. Although several screenplay drafts were completed, the producers were not happy with any of them and the project remained in "development hell" for many years. In the mid 1990s, they approached director Steven Spielberg, with whom they had made the 1975 blockbuster Jaws, to discuss their long-planned project. However, Spielberg had bought the film rights to the 1993 novel The Hammer of God by Arthur C.
Clarke, which dealt with a similar theme of an asteroid on a collision course for Earth and humanity's attempts to prevent its own extinction. Spielberg plann
