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Pale Blue Dot
''Pale Blue Dot'' is a photograph of planet Earth taken on February 14, 1990, by the ''Voyager 1'' space probe from a record distance of about kilometers ( miles, 40.5 AU), as part of that day's ''Family Portrait'' series of images of the Solar System. In the photograph, Earth's apparent size is less than a pixel; the planet appears as a tiny dot against the vastness of space, among bands of sunlight reflected by the camera. ''Voyager 1'', which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and take one last photograph of Earth across a great expanse of space, at the request of astronomer and author Carl Sagan. The phrase "Pale Blue Dot" was coined by Sagan in his reflections on the photograph's significance, documented in his 1994 book of the same name. Background In September 1977, NASA launched ''Voyager 1'', a robotic spacecraft on a mission to study the outer Solar System and eventually inters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Sagan
Carl Edward Sagan (; ; November 9, 1934December 20, 1996) was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the hypothesis, accepted since, that the high surface temperatures of Venus can be attributed to, and calculated using, the greenhouse effect.Extract of page 14 Initially an assistant professor at |
Pale Blue Dot
''Pale Blue Dot'' is a photograph of planet Earth taken on February 14, 1990, by the ''Voyager 1'' space probe from a record distance of about kilometers ( miles, 40.5 AU), as part of that day's ''Family Portrait'' series of images of the Solar System. In the photograph, Earth's apparent size is less than a pixel; the planet appears as a tiny dot against the vastness of space, among bands of sunlight reflected by the camera. ''Voyager 1'', which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and take one last photograph of Earth across a great expanse of space, at the request of astronomer and author Carl Sagan. The phrase "Pale Blue Dot" was coined by Sagan in his reflections on the photograph's significance, documented in his 1994 book of the same name. Background In September 1977, NASA launched ''Voyager 1'', a robotic spacecraft on a mission to study the outer Solar System and eventually inters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moons
A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons'', a derivation from the Moon of Earth. In the Solar System, there are six planetary satellite systems containing 209 known natural satellites altogether. Seven objects commonly considered dwarf planets by astronomers are also known to have natural satellites: , Pluto, Haumea, , Makemake, , and Eris. , there are 442 other minor planets known to have natural satellites. A planet usually has at least around 10,000 times the mass of any natural satellites that orbit it, with a correspondingly much larger diameter. The Earth–Moon system is a unique exception in the Solar System; at 3,474 kilometres (2,158 miles) across, the Moon is 0.273 times the diameter of Earth and about of its mass. The next largest ratios are the Neptune– ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-exposure Photography
Long-exposure, time-exposure, or slow-shutter photography involves using a long-duration shutter speed to sharply capture the stationary elements of images while blurring, smearing, or obscuring the moving elements. Long-exposure photography captures one element that conventional photography does not: an extended period of time. The paths of bright moving objects become clearly visible—clouds form broad bands, vehicle lights draw bright streaks, stars leave trails in the sky, and water waves appear smooth. Only bright objects leave visible trails, whereas dark objects usually disappear. Boats in long exposures disappear during the daytime, but draw bright trails from their lights at night. Technique While there is no fixed definition of what constitutes "long", the intent is to create a photo that somehow shows the effect of passing time, be it smoother waters or light trails. A 30-minute photo of a static object and surrounding cannot be distinguished from a short expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vidicon
Video camera tubes were devices based on the cathode ray tube that were used in television cameras to capture television images, prior to the introduction of charge-coupled device (CCD) image sensors in the 1980s. Several different types of tubes were in use from the early 1930s, and as late as the 1990s. In these tubes, an electron beam was scanned across an image of the scene to be broadcast focused on a target. This generated a current that was dependent on the brightness of the image on the target at the scan point. The size of the striking ray was tiny compared to the size of the target, allowing 483 horizontal scan lines per image in the NTSC format, 576 lines in PAL, and as many as 1035 lines in Hi-Vision. Cathode ray tube Any vacuum tube which operates using a focused beam of electrons, originally called cathode rays, is known as a cathode ray tube (CRT). These are usually seen as display devices as used in older (i.e., non-flat panel) television receivers and computer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wide-angle Camera
In photography and cinematography, a wide-angle lens refers to a lens whose focal length is substantially smaller than the focal length of a normal lens for a given film plane. This type of lens allows more of the scene to be included in the photograph, which is useful in architectural, interior and landscape photography where the photographer may not be able to move farther from the scene to photograph it. Another use is where the photographer wishes to emphasise the difference in size or distance between objects in the foreground and the background; nearby objects appear very large and objects at a moderate distance appear small and far away. This exaggeration of relative size can be used to make foreground objects more prominent and striking, while capturing expansive backgrounds. A wide angle lens is also one that projects a substantially larger image circle than would be typical for a standard design lens of the same focal length. This large image circle enables either la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PARADE Magazine
''Parade'' was an American nationwide Sunday newspaper magazine, distributed in more than 700 newspapers in the United States until 2022. The most widely read magazine in the U.S., ''Parade'' had a circulation of 32 million and a readership of 54.1 million. Anne Krueger has been the magazine's editor since 2015. The Nov. 13, 2022 issue was the final edition printed and inserted in newspapers nationwide. According to its final edition, ''Parade'' will continue as an e-magazine on newspaper websites. Company history The magazine was founded by Marshall Field III in 1941, with the first issue published May 31 as ''Parade: The Weekly Picture Newspaper'' for 5 cents per copy. It sold 125,000 copies that year. By 1946, ''Parade'' had achieved a circulation of 3.5 million. John Hay Whitney, publisher of the ''New York Herald Tribune'', bought ''Parade'' in 1958. Booth Newspapers purchased it in 1973. Booth was purchased by Advance Publications in 1976, and ''Parade'' became a separat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Truly
Richard Harrison Truly (born November 12, 1937) is a retired vice admiral in the United States Navy, a former fighter pilot, engineer, astronaut, and was the eighth administrator of the National Aeronautics and Space Administration (NASA) from 1989 to 1992. He was the first former astronaut to head the space agency. After his departure from NASA, he led the Georgia Tech Research Institute from 1992 to 1997, and the National Renewable Energy Laboratory from 1997 to 2005. Early life and education Born November 12, 1937, in Fayette, Mississippi, Truly attended segregated schools in Fayette and Meridian, Mississippi. He received a Bachelor of Science degree in aeronautical engineering from Georgia Institute of Technology in 1959. He was a member of the Kappa Alpha Order. He was active in the Boy Scouts of America, achieving its highest rank of Eagle Scout. Being a member of the Navy ROTC at Georgia Tech, Truly entered the U.S. Navy, where he was ordered to flight school and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA Administrator
The Administrator of the National Aeronautics and Space Administration is the highest-ranking official of NASA, the national space agency of the United States. The administrator is NASA's chief decision maker, responsible for providing clarity to the agency's vision and serving as a source of internal leadership within NASA. The office holder also has an important place within United States space policy, and is assisted by a deputy administrator. The administrator is appointed by the president of the United States, with the advice and consent of the United States Senate, and thereafter serves at the president’s pleasure. Former senator and astronaut Bill Nelson has served as the administrator since May 3, 2021. Duties and responsibilities The administrator serves as NASA's chief executive officer, accountable to the President for the leadership necessary to achieve the agency's mission. This leadership requires articulating the agency's vision, setting its programmatic and bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voyager Program
The Voyager program is an American scientific program that employs two robotic interstellar probes, ''Voyager 1'' and ''Voyager 2''. They were launched in 1977 to take advantage of a favorable alignment of Jupiter and Saturn, to fly near them while collecting data for transmission back to Earth. After launch the decision was taken to send ''Voyager 2'' near Uranus and Neptune to collect data for transmission back to Earth. As of 2022, the Voyagers are still in operation past the outer boundary of the heliosphere in interstellar space. They collect and transmit useful data to Earth. , ''Voyager 1'' was moving with a velocity of , or 17 km/s, relative to the Sun, and was from the Sun reaching a distance of from Earth as of February 10, 2022. On 25 August 2012, data from ''Voyager 1'' indicated that it had entered interstellar space. , ''Voyager 2'' was moving with a velocity of , or 15 km/s, relative to the Sun, and was from the Sun reaching a distance of from Ear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive. Saturn's interior is most likely composed of a core of iron–nickel alloy, iron–nickel and rock (silicon and oxygen compounds). Its core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally, a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's, but which has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's. The out ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
