de_dust2_2007_redone

Download this map   –    click here

In 1801, Joseph-Marie Jacquard developed a loom in which the pattern being woven was controlled by a paper tape constructed from punched cards. The paper tape could be changed without changing the mechanical design of the loom. This was a landmark achievement in programmability. His machine was an improvement over similar weaving looms. Punched cards were preceded by punch bands, as in the machine proposed by Basile Bouchon. These bands would inspire information recording for automatic pianos and more recently numerical control machine tools.

In the late 1880s, the American Herman Hollerith invented data storage on punched cards that could then be read by a machine. [21] To process these punched cards he invented the tabulator, and the key punch machine. His machines used electromechanical relays and digital counters. [22] Hollerith’s method was used in the 1890 United States Census and the completed results were “… finished months ahead of schedule and far under budget”. [23] Indeed, that census was processed two years faster than the prior census had been. [24] Hollerith’s company eventually became the core of IBM.

By 1920, the electromechanical tabulating machines could add, subtract and print accumulated totals. [25] Machine functions were directed by inserting dozens of wire jumpers into the removable control panels. When the United States instituted Social Security in 1935, IBM punched card systems were used to process records of 26 million workers. [26] Punched cards became ubiquitous in industry and government for accounting and administration.

Leslie Comrie’s articles on punched card methods and WJ Eckert’s publication of Punched Card Methods in Scientific Computation in 1940, described punched card techniques sufficiently advanced to solve some differential equations [27] or perform multiplication and division using floating point representations, all on punched cards and unit record machines. Such machines were used during World War II for cryptographic statistical processing, as well as a vast number of administrative uses. The Astronomical Computing Bureau, Columbia University performed astronomical calculations representing the state of the art in computing.

By the 20th century, earlier mechanical calculators, cash registers, accounting machines, and so on were redesigned to use electric motors, with gear position as the representation for the state of a variable. The word “computer” was a job title assigned to people who used these calculators to perform mathematical calculations. By the 1920s, British scientist Lewis Fry Richardson’s interest in weather prediction led him to propose human computers and numerical analysis to model the weather; to this day, the most powerful computers on Earth are needed to adequately model its weather using the Navier-Stokes equations. [30]

Companies like Friden, Marchant Calculator and Monroe made desktop mechanical calculators from the 1930s that could add, subtract, multiply and divide. [31] In 1948, the Curta was introduced by Austrian inventor, Curt Herzstark. It was a small, hand-cranked mechanical calculator and as such, a descendant of Gottfried Leibniz’s Stepped Reckoner and Thomas’s Arithmometer.

The world’s first all-electronic desktop calculator was the British ANITA Bell Punch, released in 1961. [32] [33] It used vacuum tubes, cold-cathode tubes and Dekatrons and its circuits, with 12 cold-cathode “Nixie” tubes for its display. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick. The tube technology was superseded in June 1963 by the US manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch (13 cm) CRT, and introduced reverse Polish notation (RPN).

A meteoroid (/ˈmiː.t̬i.ə.rɔɪd/)[1] is a small rocky or metallic body in outer space. Meteoroids are significantly smaller than asteroids, and range in size from small grains to 1 meter-wide objects.[2] Objects smaller than this are classified as micrometeoroids or space dust.[2][3][4] Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.[5][6][7]

When a meteoroid, comet, or asteroid enters the Earth’s atmosphere at a speed typically in excess of 20 km/s (72,000 km/h; 45,000 mph), aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or “shooting star”. A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower. If that object withstands ablation from its passage through the atmosphere as a meteor and impacts with the ground, it is then called a meteorite.

Around 15,000 tonnes of meteoroids, micrometeoroids and different forms of space dust enter Earth’s atmosphere each year.
In 1961, the International Astronomical Union defined a meteoroid as “a solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom”.[9][10] In 1995, Beech and Steel, writing in the Quarterly Journal of the Royal Astronomical Society, proposed a new definition where a meteoroid would be between 100 µm and 10 meters across.[11] In 2010, following the discovery of asteroids below 10 m in size, Rubin and Grossman revised the previous definition of meteoroid to objects between 10 µm and 1 m in diameter in order to maintain the distinction.[2] According to Rubin and Grossman, the minimum size of an asteroid is given by what can be discovered from Earth-bound telescopes, so the distinction between meteoroid and asteroid is fuzzy. Some of the smallest asteroids discovered (based on absolute magnitude H) are 2008 TS26 with H = 33.2[12] and 2011 CQ1 with H = 32.1[13] both with an estimated size of 1 meter.[14] Objects smaller than meteoroids are classified as micrometeoroids and cosmic dust. The Minor Planet Center does not use the term “meteoroid”.
Almost all meteoroids contain extraterrestrial nickel and iron. They have three main classifications: iron, stone, and stony-iron. Some stone meteoroids contain grain-like inclusions known as chondrules and are called chondrites. Stoney meteoroids without these features are called “achondrites”, which are typically formed from extraterrestrial igneous activity; they contain little or no extraterrestrial iron.[15] The composition of meteoroids can be inferred as they pass through the Earth’s atmosphere from their trajectories and the light spectra of the resulting meteor. Their effects on radio signals also give information, especially useful for daytime meteors, which are otherwise very difficult to observe. From these trajectory measurements, meteoroids have been found to have many different orbits, some clustering in streams (see meteor showers) often associated with a parent comet, others apparently sporadic. Debris from meteoroid streams may eventually be scattered into other orbits. The light spectra, combined with trajectory and light curve measurements, have yielded various compositions and densities, ranging from fragile snowball-like objects with density about a quarter that of ice,[16] to nickel-iron rich dense rocks. The study of meteorites also gives insights into the composition of non-ephemeral meteoroids.
Meteoroids travel around the Sun in a variety of orbits and at various velocities. The fastest ones move at about 42 kilometers per second through space in the vicinity of Earth’s orbit.[citation needed] The Earth travels at about 29.6 kilometers per second. Thus, when meteoroids meet Earth’s atmosphere head-on (which only occurs when meteors are in a retrograde orbit such as the Eta Aquarids, which are associated with the retrograde Halley’s Comet), the combined speed may reach about 71 kilometers per second. Meteoroids moving through Earth’s orbital space average about 20 km/s.[17]

On January 17, 2013 at 05:21 PST, a 1 meter-sized comet from the Oort cloud entered Earth atmosphere over a wide area in California and Nevada.[18] The object had a retrograde orbit with perihelion at 0.98 ± 0.03 AU. It approached from the direction of the constellation Virgo, and collided head-on with Earth atmosphere at 72 ± 6 km/s[18] vapourising more than 100 km above ground over a period of several seconds.