The Northrop B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying wing with a crew of two, the plane was designed by Northrop as the prime contractor, with Boeing, Hughes, and Vought as principal subcontractors, and was produced from 1987 to 2000. The bomber can drop conventional and thermonuclear weapons, such as up to eighty 500-pound class (230 kg) Mk 82 JDAM GPS-guided bombs, or sixteen 2,400-pound (1,100 kg) B83 nuclear bombs. The B-2 is the only acknowledged in-service aircraft that can carry large air-to-surface standoff weapons in a stealth configuration.
In mathematics, the Fibonacci sequence is a sequence in which each number is the sum of the two numbers that precede it. Numbers that are part of the Fibonacci sequence are known as Fibonacci numbers, commonly denoted Fn . Many writers begin the sequence with 0 and 1, although some authors start it from 1 and 1 and some from 1 and 2. Starting from 0 and 1, the sequence begins
In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities. Expressed algebraically, for quantities and with , is in a golden ratio to if
In probability theory and statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is The parameter is the mean or expectation of the distribution, while the parameter is the variance. The standard deviation of the distribution is (sigma). A random variable with a Gaussian distribution is said to be normally distributed, and is called a normal deviate.
Oxygen is a chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is the most abundant element in Earth's crust, and the third-most abundant element in the universe after hydrogen and helium.
The number π is a mathematical constant that is the ratio of a circle's circumference to its diameter, approximately equal to 3.14159. The number π appears in many formulae across mathematics and physics. It is an irrational number, meaning that it cannot be expressed exactly as a ratio of two integers, although fractions such as are commonly used to approximate it. Consequently, its decimal representation never ends, nor enters a permanently repeating pattern. It is a transcendental number, meaning that it cannot be a solution of an equation involving only finite sums, products, powers, and integers. The transcendence of π implies that it is impossible to solve the ancient challenge of squaring the circle with a compass and straightedge. The decimal digits of π appear to be randomly distributed, but no proof of this conjecture has been found.
A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself. However, 4 is composite because it is a product (2 × 2) in which both numbers are smaller than 4. Primes are central in number theory because of the fundamental theorem of arithmetic: every natural number greater than 1 is either a prime itself or can be factorized as a product of primes that is unique up to their order.
Quantum mechanics is a fundamental theory that describes the behavior of nature at and below the scale of atoms. It is the foundation of all quantum physics, which includes quantum chemistry, quantum field theory, quantum technology, and quantum information science.
In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its mean. A low standard deviation indicates that the values tend to be close to the mean of the set, while a high standard deviation indicates that the values are spread out over a wider range. The standard deviation is commonly used in the determination of what constitutes an outlier and what does not. Standard deviation may be abbreviated SD or Std Dev, and is most commonly represented in mathematical texts and equations by the lowercase Greek letter σ (sigma), for the population standard deviation, or the Latin letter s, for the sample standard deviation.
Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), that allows data exchange and delivery of power between many types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.
Voyager 2 is a space probe launched by NASA on August 20, 1977, as a part of the Voyager program. It was launched on a trajectory towards the gas giants Jupiter and Saturn and enabled further encounters with the ice giants Uranus and Neptune. It remains the only spacecraft to have visited either of the ice giant planets, and was the third of five spacecraft to achieve Solar escape velocity, which allowed it to leave the Solar System. Launched 16 days before its twin Voyager 1, the primary mission of the spacecraft was to study the outer planets and its extended mission is to study interstellar space beyond the Sun's heliosphere.
2 (two) is a number, numeral and digit. It is the natural number following 1 and preceding 3. It is the smallest and the only even prime number.
In mathematics, a function from a set X to a set Y assigns to each element of X exactly one element of Y. The set X is called the domain of the function and the set Y is called the codomain of the function.
4 (four) is a number, numeral and digit. It is the natural number following 3 and preceding 5.
The Portugal national football team has represented Portugal in men's international football competitions since 1921. The national team is controlled by the Portuguese Football Federation (FPF), the governing body for football in Portugal. Portugal's home games are played at the Estádio Nacional stadiums in Portugal, and its primary training ground and technical headquarters, Cidade do Futebol, is located in Oeiras. The head coach of the team is Roberto Martínez, and the captain is Cristiano Ronaldo, who also holds the team records for most caps and most goals.
Ashley Simon Young is an English professional footballer who plays as a full-back for Premier League club Everton.
The PlayStation 2 (PS2) is a home video game console developed and marketed by Sony Computer Entertainment. It was first released in Japan on 4 March 2000, in North America on 26 October 2000, in Europe on 24 November 2000, in Australia on 30 November 2000, and other regions thereafter. It is the successor to the PlayStation, as well as the second installment in the PlayStation brand of consoles. As a sixth-generation console, it competed with Nintendo's GameCube, Sega's Dreamcast, and Microsoft's Xbox. It is the best-selling video game console of all time, having sold over 160 million units worldwide, nearly triple the combined sales of its competing consoles.
The Academy Award for Best Actor is an award presented annually by the Academy of Motion Picture Arts and Sciences (AMPAS). It has been awarded since the 1st Academy Awards to an actor who has delivered an outstanding performance in a leading role in a film released that year. The award is traditionally presented by the previous year's Best Actress winner. However, in recent years, it has shifted towards being presented by previous years’ Best Actor winners instead.
The Academy Award for Best Actress is an award presented annually by the Academy of Motion Picture Arts and Sciences (AMPAS). It has been awarded since the 1st Academy Awards to an actress who has delivered an outstanding performance in a leading role in a film released that year. The award is traditionally presented by the previous year's Best Actor winner. However, in recent years, it has shifted towards being presented by previous years’ Best Actress winners instead.
The version history of the Android mobile operating system began with the public release of its first beta on November 5, 2007. The first commercial version, Android 1.0, was released on September 23, 2008. The operating system has been developed by Google on a yearly schedule since at least 2011. New major releases are announced at Google I/O in May along with beta testing with the stable version usually released to the public between August and October.
