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APOD
Astronomy Picture of the Day (APOD) is a website provided by NASA and Michigan Technological University (MTU). According to the website, "Each day a different image or photograph of our universe is featured, along with a brief explanation written by a professional astronomer." The photograph does not necessarily correspond to a celestial event on the exact day that it is displayed, and images are sometimes repeated. However, the pictures and descriptions often relate to current events in astronomy and space exploration. The text has several hyperlinks to more pictures and websites for more information. The images are either visible spectrum photographs, images taken at non-visible wavelengths and displayed in false color, video footage, animations, artist's conceptions, or micrographs that relate to space or cosmology. Past images are stored in the APOD Archive, with the first image appearing on June 16, 1995. This initiative has received support from NASA, the National Science Fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammatus Clouds
Mammatus (also called mamma or mammatocumulus, meaning "mammary cloud") is a cellular pattern of pouches hanging underneath the base of a cloud, typically a cumulonimbus raincloud, although they may be attached to other classes of parent clouds. The name ''mammatus'' is derived from the Latin ''mamma'' (meaning "udder" or "breast"). According to the WMO International Cloud Atlas, ''mamma'' is a cloud supplementary feature rather than a genus, species or variety of cloud. The distinct "lumpy" undersides are formed by cold air sinking down to form the pockets contrary to the puffs of clouds rising through the convection of warm air. These formations were first described in 1894 by William Clement Ley. Characteristics Mammatus are most often associated with anvil clouds and also severe thunderstorms. They often extend from the base of a cumulonimbus, but may also be found under altostratus, and cirrus clouds, as well as volcanic ash clouds. When occurring in cumulonimbus, mamm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trifid Nebula
The Trifid Nebula (catalogued as Messier 20 or M20 and as NGC 6514) is an H II region in the north-west of Sagittarius in a star-forming region in the Milky Way's Scutum-Centaurus Arm. It was discovered by Charles Messier on June 5, 1764. Its name means 'three-lobe'. The object is an unusual combination of an open cluster of stars, an emission nebula (the relatively dense, reddish-pink portion), a reflection nebula (the mainly NNE blue portion), and a dark nebula (the apparent 'gaps' in the former that cause the trifurcated appearance, also designated Barnard 85). Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favorite of amateur astronomers. The most massive star that has formed in this region is HD 164492A, an O7.5III star with a mass more than 20 times the mass of the Sun. This star is surrounded by a cluster of approximately 3100 young stars. Characteristics The Trifid Nebula was the subject of an investiga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertext
Hypertext is text displayed on a computer display or other electronic devices with references ( hyperlinks) to other text that the reader can immediately access. Hypertext documents are interconnected by hyperlinks, which are typically activated by a mouse click, keypress set, or screen touch. Apart from text, the term "hypertext" is also sometimes used to describe tables, images, and other presentational content formats with integrated hyperlinks. Hypertext is one of the key underlying concepts of the World Wide Web, where Web pages are often written in the Hypertext Markup Language (HTML). As implemented on the Web, hypertext enables the easy-to-use publication of information over the Internet. Etymology The English prefix "hyper-" comes from the Greek prefix "ὑπερ-" and means "over" or "beyond"; it has a common origin with the prefix "super-" which comes from Latin. It signifies the overcoming of the previous linear constraints of written text. The term " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opportunity (rover)
''Opportunity'', also known as MER-B (Mars Exploration Rover – B) or MER-1, is a robotic rover that was active on Mars from 2004 until 2018. ''Opportunity'' was operational on Mars for sols (). Launched on July 7, 2003, as part of NASA's Mars Exploration Rover program, it landed in Meridiani Planum on January 25, 2004, three weeks after its twin, '' Spirit'' (MER-A), touched down on the other side of the planet. With a planned 90-sol duration of activity (slightly less than 92.5 Earth days), ''Spirit'' functioned until it got stuck in 2009 and ceased communications in 2010, while ''Opportunity'' was able to stay operational for sols after landing, maintaining its power and key systems through continual recharging of its batteries using solar power, and hibernating during events such as dust storms to save power. This careful operation allowed ''Opportunity'' to operate for 57 times its designed lifespan, exceeding the initial plan by (in Earth time). By June 10, 2018, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goddard Space Flight Center
The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory located approximately northeast of Washington, D.C. in Greenbelt, Maryland, United States. Established on May 1, 1959 as NASA's first space flight center, GSFC employs approximately 10,000 civil servants and contractors. It is one of ten major NASA field centers, named in recognition of American rocket propulsion pioneer Robert H. Goddard. GSFC is partially within the former Goddard census-designated place; it has a Greenbelt mailing address.CENSUS 2000 BLOCK MAP: GODDARD CDP " U.S. Census Bureau. Retrieved on September 1, 2018. 1990 Census map of Prince George's County [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation. It was founded in 1919 and is based in Paris, France. The IAU is composed of individual members, who include both professional astronomers and junior scientists, and national members, such as professional associations, national societies, or academic institutions. Individual members are organised into divisions, committees, and working groups centered on particular subdisciplines, subjects, or initiatives. As of 2018, the Union had over 13,700 individual members, spanning 90 countries, and 82 national members. Among the key activities of the IAU is serving as a forum for scientific conferences. It sponsors nine annual symposia and holds a triannual General Assembly that sets policy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klumpke-Roberts Award
The Klumpke-Roberts Award, one of seven international and national awards for service to astronomy and astronomy education given by the Astronomical Society of the Pacific, was established from a bequest by astronomer Dorothea Klumpke-Roberts Dorothea Klumpke Roberts (August 9, 1861 in San Francisco – October 5, 1942 in San Francisco) was an American astronomer. She was Director of the Bureau of Measurements at the Paris Observatory and was made a Chevalier de la Légion d'Honn ... to honor her husband Isaac Roberts and her parents. It recognizes outstanding contributions to the public understanding and appreciation of astronomy. It is open to "individuals involved in science, education, writing/publishing, broadcasting, astronomy popularization, the arts, or other pursuits" from all nations and is the most prestigious award of its kind. Award winners SourceAstronomical Society of the Pacific See also * List of astronomy awards References {{reflist Astron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirror Website
Mirror sites or mirrors are replicas of other websites or any network node. The concept of mirroring applies to network services accessible through any protocol, such as HTTP or FTP. Such sites have different URLs than the original site, but host identical or near-identical content. Mirror sites are often located in a different geographic region than the original, or upstream site. The purpose of mirrors is to reduce network traffic, improve access speed, ensure availability of the original site for technical or political reasons, or provide a real-time backup of the original site. Mirror sites are particularly important in developing countries, where internet access may be slower or less reliable. The maintainers of some mirrors choose not to replicate the entire contents of the upstream server they are mirroring because of technical constraints, or selecting only a subset relevant to their purpose, such as software written in a particular programming language, runnable on a si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Federal Government Shutdown Of 2013
From October 1 to October 17, 2013, the United States federal government entered a shutdown and curtailed most routine operations because neither legislation appropriating funds for fiscal year 2014 nor a continuing resolution for the interim authorization of appropriations for fiscal year 2014 was enacted in time. Regular government operations resumed October 17 after an interim appropriations bill was signed into law. During the shutdown, approximately 800,000 federal employees were indefinitely furloughed, and another 1.3 million were required to report to work without known payment dates. Only those government services deemed "excepted" under the Antideficiency Act were continued; and only those employees deemed "excepted" were permitted to report to work. The previous U.S. federal government shutdown was in 1995–96. The 16-day-long shutdown of October 2013 was the third-longest government shutdown in U.S. history, after the 35-day 2018–2019 shutdown and the 21-d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-Lib Magazine
''D-Lib Magazine'' was an online magazine dedicated to digital library research and development. Past issues are available free of charge. The publication was financially supported by contributions from the D-Lib Alliance. Prior to April 2006, the magazine was sponsored by the Defense Advanced Research Project Agency (DARPA) on behalf of the Digital Libraries Initiative and by the National Science Foundation (NSF). Despite its important role in shaping the then emerging digital library community, ''D-Lib Magazine'' eventually folded due in part to an unsustainable funding model, the maturity of the field, and the rise of social media and blogs. After 22 years, 265 issues and 1062 articles ''D-Lib Magazine'' ceased publication in July 2017. ''D-Lib Magazine'' was innovative in many ways, including: HTML-only publishing (no PDF versions), open access Open access (OA) is a set of principles and a range of practices through which research outputs are distributed online, free of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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