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Topic Review
Outer Space
Outer space, or simply space, is the expanse that exists beyond the Earth and between celestial bodies. Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins (−270.45 °C; −454.81 °F). The plasma between galaxies accounts for about half of the baryonic (ordinary) matter in the universe; it has a number density of less than one hydrogen atom per cubic metre and a temperature of millions of kelvins. Local concentrations of matter have condensed into stars and galaxies. Studies indicate that 90% of the mass in most galaxies is in an unknown form, called dark matter, which interacts with other matter through gravitational but not electromagnetic forces. Observations suggest that the majority of the mass-energy in the observable universe is dark energy, a type of vacuum energy that is poorly understood. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems consist almost entirely of empty space. Outer space does not begin at a definite altitude above the Earth's surface. However, the Kármán line, an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping. The framework for international space law was established by the Outer Space Treaty, which entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space. Despite the drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit. Humans began the physical exploration of space during the 20th century with the advent of high-altitude balloon flights. This was followed by manned rocket flights and, then, manned Earth orbit, first achieved by Yuri Gagarin of the Soviet Union in 1961. Due to the high cost of getting into space, manned spaceflight has been limited to low Earth orbit and the Moon. On the other hand, unmanned spacecraft have reached all of the known planets in the Solar System. Outer space represents a challenging environment for human exploration because of the hazards of vacuum and radiation. Microgravity also has a negative effect on human physiology that causes both muscle atrophy and bone loss. In addition to these health and environmental issues, the economic cost of putting objects, including humans, into space is very high.
  • 7.1K
  • 26 Oct 2022
Topic Review
Oregon Badlands Wilderness
The Oregon Badlands Wilderness is a 29,301-acre (11,858 ha) wilderness area located east of Bend in Deschutes and Crook counties in the U.S. state of Oregon. The wilderness is managed by the Bureau of Land Management as part of the National Landscape Conservation System and was created by the Omnibus Public Land Management Act of 2009, which was signed into law by President Barack Obama on 30 March 2009. The area is known for igneous castle-like rock formations, harsh terrain, ancient Juniper trees, sagebrush, and extensive arid land. Desert wildflowers, dry river canyons, and Native American pictographs can be found. The blind iditarod racer Rachel Scdoris trained in the area, and the wilderness is home to the western terminus of the Oregon Desert Trail.
  • 372
  • 08 Nov 2022
Topic Review
Ordnance Survey
Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose (see ordnance and surveying), which was to map Scotland in the wake of the Jacobite rising of 1745. There was also a more general and nationwide need in light of the potential threat of invasion during the Napoleonic Wars. Since 1 April 2015 Ordnance Survey has operated as Ordnance Survey Ltd, a government-owned company, 100% in public ownership. The Ordnance Survey Board remains accountable to the Secretary of State for Business, Energy and Industrial Strategy. It was also a member of the Public Data Group. Paper maps for walkers represent only 5% of OS' annual revenue. They produce digital map data, online route planning and sharing services and mobile apps, plus many other location-based products for business, government and consumers. Ordnance Survey mapping is usually classified as either "large-scale" (in other words, more detailed) or "small-scale". The Survey's large-scale mapping comprises 1:2,500 maps for urban areas and 1:10,000 more generally. (The latter superseded the 1:10,560 "six inches to the mile" scale in the 1950s.) These large scale maps are typically used in professional land-use contexts and were available as sheets until the 1980s, when they were digitised. Small-scale mapping for leisure use includes the 1:25,000 "Explorer" series, the 1:50,000 "Landranger" series and the 1:250,000 road maps. These are still available in traditional sheet form. Ordnance Survey maps remain in copyright for fifty years after their publication. Some of the Copyright Libraries hold complete or near-complete collections of pre-digital OS mapping.
  • 845
  • 14 Oct 2022
Topic Review
OpenMI Standard
The OpenMI (Open Modeling Interface) Standard defines an interface that allows models to exchange data in memory at run-time. When the standard is implemented, existing models can be run simultaneously and share information, for instance at each time step, making model integration feasible at the operational level. The OpenMI standard was created with the intent to facilitate model integration, which is helpful in understanding and predicting process interactions and achieving an integrated approach to environmental management. The OpenMI standard is owned and maintained by the OpenMI Association, an open, not for profit group of international organizations and people. On the 1st of July 2014 the Open Geospatial Consortium (OGC®) membership has approved the Open Modelling Interface Standard Version 2 (OpenMI) as an OGC standard.
  • 356
  • 15 Nov 2022
Topic Review
One Tree Hill (New Zealand)
Maungakiekie / One Tree Hill is a 182-metre (597 ft) volcanic peak in Auckland, New Zealand. It is an important memorial place for both Māori and other New Zealanders. The suburb around the base of the hill is also called One Tree Hill. It is surrounded by the suburbs of Royal Oak to the west, and clockwise, Epsom, Greenlane, Oranga, and Onehunga. The summit provides views across the Auckland area, and allows visitors to see both of Auckland's harbours. The hill's scoria cones were erupted from three craters – one is intact and two have been breached by lava flows that rafted away part of the side of the scoria cone. Lava flows went in all directions, many towards Onehunga, covering an area of 20 square kilometres (7.7 sq mi), making it the second largest (in area covered) of the Auckland volcanic field, behind Rangitoto Island. The volcano erupted approximately 60,000 years ago.
  • 1.5K
  • 10 Nov 2022
Topic Review
Ocean-bottom Seismometer
An ocean-bottom seismometer (OBS) is a seismometer that is designed to record the earth motion under oceans and lakes from man-made sources and natural sources. Sensors at the sea floor are used to observe acoustic and seismic events. Seismic and acoustic signals may be caused by different sources, by earthquakes and tremors as well as by artificial sources. Computing and analyzing the data yields information about the kind of source and, in case of natural seismic events, the geophysics and geology of the sea floor and the deeper crust. The deployment of OBS along a profile will give information about the deep structure of the Earth's crust and upper mantle in offshore areas. OBS may be equipped with a maximum of a three-component geophone in addition to a hydrophone, and thus it needs a capacity of more than 144 Mbytes, which would be the minimum for an adequate MCS profiling. In a typical survey, the instruments should be operational for several days (deployments can exceed 12 months), which requires a data storage capacity of more than 500 Mbyte. Other experiments, such as tomographic investigations within a 3D-survey or seismological monitoring, demand even larger capacities.
  • 534
  • 08 Oct 2022
Topic Review
Nostocyclopeptides
Nostocyclopeptides (Ncps) are a small class of bioactive nonribosomal peptides thus far identified only in cyanobacteria of the genus Nostoc. They are composed of six-seven amino acid residues and contain a unique imino linkage formed between C-terminal aldehyde and an N-terminal amine group of the conserved tyrosine. Nostocyclopeptides occur both in cyclic and linear form.
  • 433
  • 05 Nov 2021
Topic Review
Northwestern European People
Northwestern European people are a pan-ethnic group, or multi-ethnic regional grouping, and the inhabitants of Northwestern Europe. Northwest or Northwestern Europeans can usually trace back full or partial heritage to Great Britain and Ireland, Northern Germany, Denmark , Sweden, Norway , the Netherlands, Northern France, Belgium, and other places connected to Northwestern Europe geographically or culturally. As the pan-ethnic group is also a cultural category, rather than exclusively geographical; it often can include peoples with ancestry from bordering regions such as Austria, Finland , Southern Germany, and Switzerland . There is a large Northwestern European diaspora, with significant numbers within North America (Northwestern European Americans and Northwestern European Canadians), and Northwestern European Australians in Oceania. Other subgroupings of Europeans include Eastern European people and Southern European people.
  • 19.0K
  • 28 Oct 2022
Topic Review
Northern Cheyenne Indian Reservation
The Northern Cheyenne Tribe of the Northern Cheyenne Indian Reservation (Template:Lang-chy; formerly named the Tongue River) is the federally recognized Northern Cheyenne tribe. Located in southeastern Montana, the reservation is approximately 690 square miles (1,800 km2) in size and home to approximately 5,000 Cheyenne people. The tribal and government headquarters are located in Lame Deer, also the home of the annual Northern Cheyenne pow wow. The reservation is bounded on the east by the Tongue River and on the west by the Crow Reservation. There are small parcels of non-contiguous off-reservation trust lands in Meade County, South Dakota, northeast of the city of Sturgis. Its timbered ridges that extend into northwestern South Dakota are part of Custer National Forest and it is approximately 40 miles (64 km) east of the site of the 1876 Battle of the Little Bighorn. According to tribal enrollment figures as of March 2013, there were approximately 10,050 enrolled tribal members, of which about 4,939 were residing on the reservation,Template:Full short with approximately 91% of the population Native American (full or part blood quantum) and 72.8% identifying as Cheyenne. Slightly more than a quarter of the population five years or older spoke a language other than English. Members of the Crow Nation also live on the reservation.
  • 434
  • 23 Nov 2022
Topic Review
Normal Gravity Formula
Normal gravity formulas are mathematical expressions, with which the free-fall acceleration at a point in vicinity to the surface of the earth can be estimated. Along with the mass (known or predicted) of a body, the weight is calculated.
  • 4.2K
  • 10 Nov 2022
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