A computer monitor or a computer display is an electronic visual display for computers. A monitor usually comprises the display device, casing, the display device in modern monitors is typically a thin film transistor liquid crystal display or a flat panel LED display, while older monitors used a cathode ray tubes. It can be connected to the computer via VGA, DVI, HDMI, DisplayPort, Thunderbolt, LVDS or other proprietary connectors, computer monitors were used for data processing while television receivers were used for entertainment. From the 1980s onwards, computers have used for both data processing and entertainment, while televisions have implemented some computer functionality. The common aspect ratio of televisions, and computer monitors, has changed from 4,3 to 16,10, to 16,9. Early electronic computers were fitted with a panel of light bulbs where the state of each particular bulb would indicate the state of a particular register bit inside the computer. This allowed the operating the computer to monitor the internal state of the machine.
As early monitors were only capable of displaying a limited amount of information. Instead, a printer was the primary output device, while the monitor was limited to keeping track of the programs operation. Multiple technologies have used for computer monitors. Until the 21st century most used cathode ray tubes but they have largely superseded by LCD monitors. The first computer monitors used cathode ray tubes, high-resolution CRT displays were developed for specialized military and scientific applications but they were far too costly for general use. Either computer could be connected to the terminals of an ordinary color TV set or used with a purpose-made CRT color monitor for optimum resolution. In 1984 IBM introduced the Enhanced Graphics Adapter which was capable of producing 16 colors and had a resolution of 640 x 350, by the end of the 1980s color CRT monitors that could clearly display 1024 x 768 pixels were widely available and increasingly affordable. During the following decade maximum display resolutions gradually increased and prices continued to fall, CRT technology remained dominant in the PC monitor market into the new millennium partly because it was cheaper to produce and offered viewing angles close to 180 degrees.
CRTs still offer some image quality advantages over LCDs but improvements to the latter have made much less obvious. There are multiple technologies that have used to implement liquid crystal displays. Commonly, the laptop would be offered with an assortment of display options at increasing price points, monochrome
Military colours, standards and guidons
The Roman Empire made battle standards a part of their vast armies. It was formalized in the armies of Europe in the High Middle Ages, as armies became trained and adopted set formations, each regiments ability to keep its formation was potentially critical to its, and therefore its armys, success. In the chaos of battle, not least due to the amount of dust and smoke on a battlefield, Regimental flags are generally awarded to a regiment by a head-of-State during a ceremony. They were therefore treated with reverence as they represented the honour, Colours may be inscribed with the names of battles or other symbols representing former achievements. Regiments tended to adopt colour guards, composed of experienced or élite soldiers, as a result, the capture of an enemys standard was considered as a great feat of arms. They are never capriciously destroyed – when too old to use they are replaced and laid-up in museums, religious buildings and other places of significance to their regiment. However, in most modern armies, standing orders now call for the Colours to be destroyed if they are ever in jeopardy of being captured by the enemy.
Due to the advent of modern weapons, and subsequent changes in tactics, Colours are no longer carried into battle, but continue to be used at events of formal character. The Armed Forces of the Argentine Republics military Colours of the Argentine Army, Argentine Navy and Argentine Air Force are the Flag of Argentina as the National War Colour and the Unit Colour. The National War Colour is a variation of the Argentine national flag made for use, while the Unit Colour differs per service arm. Only the Regiment of Patricians uses company colors, cadet squadron colours are used by the Argentine Air Force Academy. Units of the Brazilian Armed Forces carry a stand of two Colours, differing per service, the standard of the Army measures 80 ×120 cm, white with the Army coat of arms in the centre, trimmed with gold fringe. The name of the service is inscribed in letters on a green scroll beneath the shield. Above the shield is a helmet with red and sky blue mantling. The staff is topped by a nickel-plated lance-head finial,32 cm high, ten red streamers with campaign honours inscribed in sky blue letters are attached below the lance-head.
The staff is 212 cm long, not including the lance-head and it is covered in sky blue velvet with a red spiral strip. The colour belt is 10 cm in width, covered with sky blue velvet with red velvet stripes, the Navys flag uses dark blue colours, the Air Force flag ultramarine blue. Brazilian military units carry the flag as a National Colour
RGB color model
The RGB color model is an additive color model in which red and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three primary colors, red and blue. Before the electronic age, the RGB color model already had a theory behind it. Thus an RGB value does not define the same color across devices without some kind of color management, typical RGB input devices are color TV and video cameras, image scanners, video games, and digital cameras. Typical RGB output devices are TV sets of technologies and mobile phone displays, video projectors, multicolor LED displays. Color printers, on the hand are not RGB devices. This article discusses concepts common to all the different color spaces that use the RGB color model, to form a color with RGB, three light beams must be superimposed. Each of the three beams is called a component of color, and each of them can have an arbitrary intensity, from fully off to fully on. The RGB color model is additive in the sense that the three beams are added together, and their light spectra add, wavelength for wavelength.
This is essentially opposite to the color model that applies to paints, dyes. When the intensities for all the components are the same, the result is a shade of gray, darker or lighter depending on the intensity. When the intensities are different, the result is a colorized hue, a secondary color is formed by the sum of two primary colors of equal intensity, cyan is green+blue, magenta is red+blue, and yellow is red+green. The RGB color model itself does not define what is meant by red and blue colorimetrically, and so the results of mixing them are not specified as absolute, but relative to the primary colors. When the exact chromaticities of the red and blue primaries are defined, the normal three kinds of light-sensitive photoreceptor cells in the human eye respond most to yellow and violet light. As an example, suppose that light in the range of wavelengths enters the eye. Light of these wavelengths would activate both the medium and long wavelength cones of the retina, but not equally—the long-wavelength cells will respond more, the difference in the response can be detected by the brain, and this difference is the basis of our perception of orange.
Thus, the appearance of an object results from light from the object entering our eye and stimulating the different cones simultaneously. The first experiments with RGB in early color photography were made in 1861 by Maxwell himself, to reproduce the color photograph, three matching projections over a screen in a dark room were necessary
Ultraviolet is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the light output of the Sun. It is produced by electric arcs and specialized lights, such as lamps, tanning lamps. Consequently, the effects of UV are greater than simple heating effects. Suntan and sunburn are familiar effects of over-exposure, along with risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earths atmosphere. More-energetic, shorter-wavelength extreme UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground, Ultraviolet is responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has both beneficial and harmful to human health. Ultraviolet rays are invisible to most humans, the lens in a human eye ordinarily filters out UVB frequencies or higher, and humans lack color receptor adaptations for ultraviolet rays.
Under some conditions and young adults can see ultraviolet down to wavelengths of about 310 nm, near-UV radiation is visible to some insects and birds. Small birds have a fourth color receptor for ultraviolet rays, this gives birds true UV vision, reindeer use near-UV radiation to see polar bears, who are poorly visible in regular light because they blend in with the snow. UV allows mammals to see urine trails, which is helpful for animals to find food in the wild. The males and females of some species look identical to the human eye. Ultraviolet means beyond violet, violet being the color of the highest frequencies of visible light, Ultraviolet has a higher frequency than violet light. He called them oxidizing rays to emphasize chemical reactivity and to them from heat rays. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, in 1878 the effect of short-wavelength light on sterilizing bacteria was discovered. By 1903 it was known the most effective wavelengths were around 250 nm, in 1960, the effect of ultraviolet radiation on DNA was established.
The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is absorbed by air, was made in 1893 by the German physicist Victor Schumann
Messier 66 is an intermediate spiral galaxy about 36 million light-years away in the constellation Leo. It was discovered by Charles Messier in 1780, M66 is about 95 thousand light-years across with striking dust lanes and bright star clusters along sweeping spiral arms. M66 is part of the Leo Triplet, a group of galaxies that includes M65. As of 2015, four supernovae have been observed in M66, the latter feature shows up visually as an extremely prominent and unusual spiral arm and dust lane structures as originally noted in the Atlas of Peculiar Galaxies. SEDS, Spiral Galaxy M66 Spiral Galaxy M66 Astronomy Picture of the Day – Unusual Spiral Galaxy M66 from Hubble –2010 April 13 Merrifield, Szymanek, Nik. Messier 66 on WikiSky, DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Sky Map and images
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it is referred to as the Red Planet because the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the valleys and polar ice caps of Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System. The smooth Borealis basin in the northern hemisphere covers 40% of the planet, Mars has two moons and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan, there are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life.
Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers, liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is about 6⁄1000 that of the Earths, except at the lowest elevations for short periods. The two polar ice caps appear to be largely of water. The volume of ice in the south polar ice cap, if melted. On November 22,2016, NASA reported finding a large amount of ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior, Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.91, which is surpassed only by Jupiter, the Moon, optical ground-based telescopes are typically limited to resolving features about 300 kilometers across when Earth and Mars are closest because of Earths atmosphere. Mars is approximately half the diameter of Earth with an area only slightly less than the total area of Earths dry land.
Mars is less dense than Earth, having about 15% of Earths volume and 11% of Earths mass, the red-orange appearance of the Martian surface is caused by iron oxide, or rust. It can look like butterscotch, other common colors include golden, tan. Like Earth, Mars has differentiated into a metallic core overlaid by less dense materials. Current models of its interior imply a core with a radius of about 1,794 ±65 kilometers, consisting primarily of iron and this iron sulfide core is thought to be twice as rich in lighter elements than Earths. The core is surrounded by a mantle that formed many of the tectonic and volcanic features on the planet
Mars Science Laboratory
Mars Science Laboratory is a robotic space probe mission to Mars launched by NASA on November 26,2011, which successfully landed Curiosity, a Mars rover, in Gale Crater on August 6,2012. The overall objectives include investigating Mars habitability, studying its climate and geology, the rover carries a variety of scientific instruments designed by an international team. MSL successfully carried out the most accurate Martian landing of any spacecraft, hitting a small target landing ellipse of only 7 by 20 km. In the event, MSL achieved a landing 2.4 km east and 400 m north of the center of the target and this location is near the mountain Aeolis Mons. The rover mission is set to explore for at least 687 Earth days over a range of 5 by 20 km, the total cost of the MSL project is about US$2.5 billion. Mars rovers include Sojourner from the Mars Pathfinder mission and the Mars Exploration Rovers Spirit, Curiosity is about twice as long and five times as heavy as Spirit and Opportunity, and carries over ten times the mass of scientific instruments.
The MSL mission has four scientific goals, Determine the landing sites habitability including the role of water, the study of the climate and it is useful preparation for a future manned mission to Mars. This data would be important for a manned mission. The MSL spacecraft includes spaceflight-specific instruments, in addition to utilizing one of the rover instruments—Radiation assessment detector —during the spaceflight transit to Mars. MSL EDL Instrument, The MEDLI projects main objective is to measure aerothermal environments, sub-surface heat shield material response, vehicle orientation, the MEDLI instrumentation suite was installed in the heatshield of the MSL entry vehicle. The acquired data will support future Mars missions by providing measured atmospheric data to validate Mars atmosphere models, MEDLI instrumentation consists of three main subsystems, MEDLI Integrated Sensor Plugs, Mars Entry Atmospheric Data System and the Sensor Support Electronics. Each computers memory includes 256 KB of EEPROM,256 MB of DRAM and this compares to 3 MB of EEPROM,128 MB of DRAM, and 256 MB of flash memory used in the Mars Exploration Rovers.
The RCE computers use the RAD750 CPU operating at 200 MHz, the RAD750 CPU is capable of up to 400 MIPS, while the RAD6000 CPU is capable of up to 35 MIPS. Of the two computers, one is configured as backup, and will take over in the event of problems with the main computer. The rover has an Inertial Measurement Unit that provides 3-axis information on its position, the rovers computers are constantly self-monitoring to keep the rover operational, such as by regulating the rovers temperature. Activities such as taking pictures and operating the instruments are performed in a sequence that is sent from the flight team to the rover. The rovers computers function on VxWorks, an operating system from Wind River Systems. Once landed, the applications were replaced with software for driving on the surface, Curiosity is equipped with several means of communication, for redundancy
X-radiation is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz, X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. Spelling of X-ray in the English language includes the variants x-ray, xray, X-rays with high photon energies are called hard X-rays, while those with lower energy are called soft X-rays. Due to their ability, hard X-rays are widely used to image the inside of objects, e. g. in medical radiography. The term X-ray is metonymically used to refer to an image produced using this method. Since the wavelengths of hard X-rays are similar to the size of atoms they are useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air, the length of 600 eV X-rays in water is less than 1 micrometer. There is no consensus for a definition distinguishing between X-rays and gamma rays, one common practice is to distinguish between the two types of radiation based on their source, X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus.
This definition has problems, other processes can generate these high-energy photons. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m and this criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. Occasionally, one term or the other is used in specific contexts due to precedent, based on measurement technique. Thus, gamma-rays generated for medical and industrial uses, for radiotherapy, in the ranges of 6–20 MeV. X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds and this makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a period of time causes radiation sickness. In medical imaging this increased risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in treatment to kill malignant cells using radiation therapy.
It is used for material characterization using X-ray spectroscopy, hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects, the most often seen applications are in medical radiography and airport security scanners, but similar techniques are important in industry and research
It is the largest estuary in North America. With its northern portion in Maryland and the part in Virginia. More than 150 major rivers and streams flow into the bays 64, 299-square-mile drainage basin, the bay is approximately 200 miles long from its northern headwaters in the Susquehanna River to its outlet in the Atlantic Ocean. It is 2.8 miles wide at its narrowest and 30 miles at its widest, total shoreline including tributaries is 11,684 miles, circumnavigating a surface area of 4,479 square miles. Average depth is 21 feet, reaching a maximum of 174 feet, the bay is spanned twice, in Maryland by the Chesapeake Bay Bridge from Sandy Point to Kent Island and in Virginia by the Chesapeake Bay Bridge-Tunnel connecting Virginia Beach to Cape Charles. Known for both its beauty and bounty, the bay became emptier, with crabs, oysters. Recent restoration efforts begun in the 1990s have been ongoing and show potential for growth of the oyster population. The health of the Chesapeake Bay improved in 2015, marking three years of gains over the past four years, according to a new report by the University of Maryland, the word Chesepiooc is an Algonquian word referring to a village at a big river.
It is the seventh oldest surviving English place-name in the U. S. first applied as Chesepiook by explorers heading north from the Roanoke Colony into a Chesapeake tributary in 1585 or 1586. The name may refer to the Chesepian or Chesapeake people. They occupied an area which is now the Norfolk, Chesapeake, in 2005, Algonquian linguist Blair Rudes helped to dispel one of the areas most widely held beliefs, that Chesapeake means something like great shellfish bay. The name might actually have meant something like great water, or it might have just referred to a location at the bays mouth. In addition, the name is almost always prefixed by the in usage by local residents, The Chesapeake, The Chesapeake Bay, the Chesapeake Bay is an estuary to the North Atlantic, lying between the Delmarva Peninsula to the east and the North American mainland to the west. It is the ria, or drowned valley, of the Susquehanna River and it is not a fjord, because the Laurentide Ice Sheet never reached as far south as the northernmost point on the bay.
The large rivers entering the bay from the west have broad mouths and are extensions of the ria for miles up the course of each river. The bay was formed starting about 10,000 years ago when rising sea levels at the end of the last ice age flooded the Susquehanna River valley. Parts of the bay, especially the Calvert County and these cliffs, generally known as Calvert Cliffs, are famous for their fossils, especially fossilized shark teeth which are commonly found washed up on the beaches next to the cliffs. Scientists Cliffs is a community in Calvert County named for the desire to create a retreat for scientists when the community was founded in 1935
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called light or simply light. A typical human eye will respond to wavelengths from about 390 to 700 nm, in terms of frequency, this corresponds to a band in the vicinity of 430–770 THz. The spectrum does not, contain all the colors that the human eyes, unsaturated colors such as pink, or purple variations such as magenta, are absent, for example, because they can be made only by a mix of multiple wavelengths. Colors containing only one wavelength are called pure colors or spectral colors. Visible wavelengths pass through the window, the region of the electromagnetic spectrum that allows wavelengths to pass largely unattenuated through the Earths atmosphere. An example of this phenomenon is that clean air scatters blue light more than red wavelengths, the optical window is referred to as the visible window because it overlaps the human visible response spectrum.
The near infrared window lies just out of the vision, as well as the Medium Wavelength IR window. In the 13th century, Roger Bacon theorized that rainbows were produced by a process to the passage of light through glass or crystal. In the 17th century, Isaac Newton discovered that prisms could disassemble and reassemble white light and he was the first to use the word spectrum in this sense in print in 1671 in describing his experiments in optics. The result is red light is bent less sharply than violet as it passes through the prism. Newton divided the spectrum into seven named colors, orange, green, indigo, the human eye is relatively insensitive to indigos frequencies, and some people who have otherwise-good vision cannot distinguish indigo from blue and violet. For this reason, some commentators, including Isaac Asimov, have suggested that indigo should not be regarded as a color in its own right. However, the evidence indicates that what Newton meant by indigo, comparing Newtons observation of prismatic colors to a color image of the visible light spectrum shows that indigo corresponds to what is today called blue, whereas blue corresponds to cyan.
In the 18th century, Goethe wrote about optical spectra in his Theory of Colours, Goethe used the word spectrum to designate a ghostly optical afterimage, as did Schopenhauer in On Vision and Colors. Goethe argued that the spectrum was a compound phenomenon. Where Newton narrowed the beam of light to isolate the phenomenon, Goethe observed that a wider aperture produces not a spectrum but rather reddish-yellow, the spectrum appears only when these edges are close enough to overlap. Young was the first to measure the wavelengths of different colors of light, the connection between the visible spectrum and color vision was explored by Thomas Young and Hermann von Helmholtz in the early 19th century
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object and thus in contrast to on-site observation. It may be split into active remote sensing and passive remote sensing, passive sensors gather radiation that is emitted or reflected by the object or surrounding areas. Reflected sunlight is the most common source of radiation measured by passive sensors, examples of passive remote sensors include film photography, charge-coupled devices, and radiometers. Active collection, on the hand, emits energy in order to scan objects and areas whereupon a sensor detects. RADAR and LiDAR are examples of remote sensing where the time delay between emission and return is measured, establishing the location and direction of an object. Remote sensing makes it possible to data of dangerous or inaccessible areas. Remote sensing applications include monitoring deforestation in areas such as the Amazon Basin, glacial features in Arctic and Antarctic regions, military collection during the Cold War made use of stand-off collection of data about dangerous border areas.
Remote sensing replaces costly and slow data collection on the ground, the basis for multispectral collection and analysis is that of examined areas or objects that reflect or emit radiation that stand out from surrounding areas. For a summary of major remote sensing satellite systems see the overview table, conventional radar is mostly associated with aerial traffic control, early warning, and certain large scale meteorological data. Other types of active collection includes plasmas in the ionosphere, interferometric synthetic aperture radar is used to produce precise digital elevation models of large scale terrain. Laser and radar altimeters on satellites have provided a range of data. By measuring the bulges of water caused by gravity, they map features on the seafloor to a resolution of a mile or so, by measuring the height and wavelength of ocean waves, the altimeters measure wind speeds and direction, and surface ocean currents and directions. Ultrasound and radar tide gauges measure sea level and wave direction in coastal, light detection and ranging is well known in examples of weapon ranging, laser illuminated homing of projectiles.
Vegetation remote sensing is an application of LIDAR. Radiometers and photometers are the most common instrument in use, collecting reflected and emitted radiation in a range of frequencies. The most common are visible and infrared sensors, followed by microwave, gamma ray and rarely and they may be used to detect the emission spectra of various chemicals, providing data on chemical concentrations in the atmosphere. Simultaneous multi-spectral platforms such as Landsat have been in use since the 1970s and these thematic mappers take images in multiple wavelengths of electro-magnetic radiation and are usually found on Earth observation satellites, including the Landsat program or the IKONOS satellite. Landsat images are used by agencies such as KYDOW to indicate water quality parameters including Secchi depth, chlorophyll a density
A space telescope or space observatory is an instrument located in outer space to observe distant planets and other astronomical objects. Space telescopes avoid many of the problems of ground-based observatories, such as pollution and distortion of electromagnetic radiation. In addition, ultraviolet frequencies, X-rays and gamma rays are blocked by the Earths atmosphere, Space telescopes are distinct from other imaging satellites pointed toward Earth for purposes of espionage, weather analysis and other types of information gathering. Spitzers proposal called for a telescope that would not be hindered by Earths atmosphere. Performing astronomy from ground-based observatories on Earth is limited by the filtering, some terrestrial telescopes can reduce atmospheric effects with adaptive optics. A telescope orbiting Earth outside the atmosphere is subject neither to twinkling nor to light pollution from artificial light sources on Earth, as a result, the angular resolution of space telescopes is often much smaller than a ground-based telescope with a similar aperture.
Infrared and ultraviolet are largely blocked, all these advantages do come with a price. Space telescopes are much more expensive to build than ground-based telescopes, due to their location, space telescopes are extremely difficult to maintain. The Hubble Space Telescope was serviced by the Space Shuttle while many other space telescopes cannot be serviced at all, Space observatories can generally be divided into two classes, missions which map the entire sky, and observatories which focus on selected astronomical objects or parts of the sky. Many space observatories have already completed their missions, while others continue operating, satellites have been launched and operated by NASA, ISRO, ESA, Japanese Space Agency and the Soviet space program succeeded by Roskosmos of Russia. Many space telescopes have been launched, as of February 2017, over 20 telescopes are known to be operational