The Very Large Telescope Project (VLT) consists of a system of four separate optical telescopes (the Antu telescope, the Kueyen telescope, the Melipal telescope, and the Yepun telescope) organized in an array formation. Each telescope has an 8.2 m aperture. The project is organized by the European Southern Observatory. VLT is located at the Paranal Observatory on Cerro Paranal, a 2,635 m high mountain in the Atacama desert in northern Chile. Very Large Telescope - General informa ...

Including:

• Very Large Telescope - General information
• Very Large Telescope - Interferometry and the VLTI

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A karyotype is the complete set of all chromosomes of a cell of any living organism. The chromosomes are arranged and displayed (often on a photo) in a standard format: in pairs, ordered by size. Karyotypes are examined in searches for chromosomal aberrations, and may be used to determine other macroscopically visible aspects of an individual's genotype, such as sex (XX vs. XY pair). The s ...

Including:

• Karyotype - Classic karyotype
• Karyotype - Spectral karyotype SKY technique

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The metre (Commonwealth English) or meter (American English) (symbol: m) is the SI base unit of length. It is defined as the length of the path travelled by light in absolute vacuum during a time interval of 1/299,792,458 of a second. Adding SI prefixes to metre creates multiples and submultiples; for example kilometre (1000 metres; kilo- = 1000) and millimetre (one thousandth of a metre; milli- = 1 / 1 000). Metre - SI prefixes applied to the metre. The metr ...

Including:

• Metre - SI prefixes applied to the metre
• Metre - Conversions
• Metre - History
• Metre - Timeline of definition

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Very Long Baseline Interferometry (VLBI) is a type of interferometry in which the data received at each antenna in the array is paired with timing information, usually from a local atomic clock, and then stored for later analysis on magnetic tape or hard disk. At that later time, the data are correlated with data from other antennas similarly recorded, to produce the resulting image. The resolution achievable using interferometry is proportional to the distance between the antennas furthest apart in the array. The VLBI technique enabl ...

Including:

• Very Long Baseline Interferometry - Space VLBI
• Very Long Baseline Interferometry - How VLBI Works

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Betelgeuse (Alpha (α) Orionis) is a semiregular variable star located about 450 light-years away [1]. It is the second brightest star in the constellation Orion, and the tenth brightest star in the nighttime sky. Although it has the Bayer designation "alpha", it is not as bright as Rigel (Beta Orionis). It is a vertex of the Winter Triangle asterism. Betelgeuse is a red supergiant, one of the physically largest stars known. If it was placed at the center of our solar system, its outer surface would extend well beyond the orbit ...

Including:

• Betelgeuse - Origin of the name Betelgeuse
• Betelgeuse - Distinguishing characteristics
• Betelgeuse - References in fiction

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In physics, VIRGO is a project of France and Italy, a Michelson laser interferometer that is analogous to LIGO. VIRGO physics - External link. Virgo - description ...

Including:

• VIRGO physics - External link

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Aperture Masking Interferometry is a form of speckle interferometry, allowing diffraction limited imaging from ground based telescopes. This technique allows ground based telescopes to reach the maximum possible resolution, allowing ground-based telescopes with large diameters to produce far sharper images than the Hubble Space Telescope. The principle limitation of the technique is that it is limited to relatively bright astronomical objects. A mask is placed over the telescope which only allows light through a small number of holes. ...

Including:

• Aperture Masking Interferometry - External links
• Aperture Masking Interferometry - References

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For other uses, see vacuum cleaner and Vacuum (musical group). The root of the word vacuum is the Latin word vacuus (pl. vacua) which means "empty." In physics, a vacuum is a volume of space that is empty of matter and radiation, including air, so that gaseous pressure is much less than standard atmospheric pressure. Vacuum - Vacuum ranges. Vacuum ranges do not have universally agreed definitions and often depend on the size of the vacuum chamber, but a typical distr ...

Including:

• Vacuum - Vacuum ranges
• Vacuum - Perfect vacuum
• Vacuum - Partial vacuum
• Vacuum - Degrees of vacuum
• Vacuum - Creating a vacuum
• Vacuum - High vacuum
• Vacuum - Ultra-high vacuum
• Vacuum - Vacuum in space
• Vacuum - The quantum-mechanical vacuum
• Vacuum - Historical interpretation

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The Multi-Element Radio Linked Interferometer Network (MERLIN) is an array of radio telescopes spread across Britain. The array is run from Jodrell Bank Observatory in Cheshire by the University of Manchester on behalf of PPARC as a National Facility. The array consists of up to seven radio telescopes and includes the Lovell Telescope, MkII, Cambridge, Defford, Knockin, Darnhall and Pickmere (previously known as Tabley). The longest baseline is therefore 217km and MERLIN can operate at frequencies between 151 MHz and 24 ...

Including:

• MERLIN - History
• MERLIN - The e-MERLIN upgrade
• MERLIN - Telescope information

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Albert Abraham Michelson, (pronunciation anglicized as "Michael-son", December 19, 1852 - May 9, 1931), was a Prussian-born American physicist known for his work on the measurement of the speed of light, and especially for the Michelson-Morley experiment. In 1907 he received a Nobel prize for physics, the first American to receive the Nobel Prize in the sciences. Albert Abraham Michelson - Life. Michelson was born in Strzelno, Poland (then Strelno, Provinz Posen Kingdom of Prussia) in 1852, the son of a Jew ...

Including:

• Albert Abraham Michelson - Life
• Albert Abraham Michelson - Speed of light
• Albert Abraham Michelson - Early measurements
• Albert Abraham Michelson - Mount Wilson and Lookout Mountain 1926
• Albert Abraham Michelson - Michelson Pease & Pearson 1932
• Albert Abraham Michelson - Interferometry
• Albert Abraham Michelson - Astronomical interferometry
• Albert Abraham Michelson - Reference in Bonanza television series
• Albert Abraham Michelson - Electronic books

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Albert Abraham Michelson - Early measurements. As early as 1877, while still an officer in the US Navy, Michelson started planning a refinement of the rotating-mirror method of Léon Foucault for measuring the speed of light, using improved optics and a longer baseline. He conducted some preliminary measurements using largely improvised equipment in 1878 about which time his work came to the attention of Simon Newcomb, director of the Nautical Almanac Office who was already advanced in planning his own study. Mic ...

See also:

Albert Abraham Michelson, Albert Abraham Michelson - Life, Albert Abraham Michelson - Speed of light, Albert Abraham Michelson - Early measurements, Albert Abraham Michelson - Mount Wilson and Lookout Mountain 1926, Albert Abraham Michelson - Michelson Pease & Pearson 1932, Albert Abraham Michelson - Interferometry, Albert Abraham Michelson - Astronomical interferometry, Albert Abraham Michelson - Reference in Bonanza television series, Albert Abraham Michelson - Electronic books

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George Ellery Hale received the 60 inch (1.5 m) blank mirror, cast by Saint Gobain in France, in 1896 as a gift from his father, William Hale. It was a glass disk 7 1/2 inches (191 mm) thick and weighing 1900 pounds (860 kg). However it was not until 1904 that Hale received funding from the Carnegie Institution to build an observatory. Grinding began in 1905 and took two years. The mounting and structure for the telescope was built in San Francisco and barely survived the 1906 earthquake. Transporting the pieces to the top of Mount Wilson wa ...

See also:

Mount Wilson Observatory, Mount Wilson Observatory - 60 inch 1.5 m Hale telescope, Mount Wilson Observatory - 100 inch 2.5 m Hooker telescope, Mount Wilson Observatory - Solar telescopes, Mount Wilson Observatory - Interferometry

Read more here: » Mount Wilson Observatory: Encyclopedia II - Mount Wilson Observatory - 60 inch 1.5 m Hale telescope

The aether drag hypothesis is historically important because it was one of the reasons why Newton's corpuscular theory of light was replaced by the wave theory and it is used in early explanations of light propagation without relativity theory. It originated as a result of early attempts to measure the speed of light. In 1810 François Arago realised that variations in the refractive index of a substance predicted by the corpuscular theory would provide a useful method for measuring the velocity of light. These predictions arose becau ...

See also:

Aether drag hypothesis, Aether drag hypothesis - Historical importance, Aether drag hypothesis - Bibliography and References

Read more here: » Aether drag hypothesis: Encyclopedia II - Aether drag hypothesis - Historical importance

Speed of light - Constant velocity from all reference frames. It is important to realise that the speed of light is not a "speed limit" in the conventional sense. An observer chasing a beam of light will measure it moving away from him at the same speed as a stationary observer. This leads to some unusual consequences for velocities. Most individuals are accustomed to the addition rule of velocities: if two cars approach each other from opposite directions, each travelling at a speed of 50 kilometres per h ...

See also:

Speed of light, Speed of light - Overview, Speed of light - Communications, Speed of light - Physics, Speed of light - Constant velocity from all reference frames, Speed of light - Interaction with transparent materials, Speed of light - Faster-than-light observations and experiments, Speed of light - Light-slowing experiments, Speed of light - History, Speed of light - Medieval and early modern theories, Speed of light - Measurement of the speed of light, Speed of light - Relativity

Read more here: » Speed of light: Encyclopedia II - Speed of light - Physics

LIGO's mission is to observe directly gravitational waves of cosmic origin. These waves were first predicted by Einstein's Theory of General Relativity in 1916, when the technology necessary for their detection did not yet exist. Gravitational waves were indirectly confirmed to exist since observations were made of the binary pulsar PSR 1913+16, for which the Nobel Prize was awarded in 1993. Direct detection of gravitational waves has long been sought, for it would open up a new branch of astronomy to complement electromagnetic telesc ...

See also:

LIGO, LIGO - Mission, LIGO - Observatories, LIGO - Operation, LIGO - Observations

Read more here: » LIGO: Encyclopedia II - LIGO - Mission

Awards Bruce Medal in 1942 Gold Medal of the Royal Astronomical Society in 1946 Henry Norris Russell Lectureship in 1951 Named after him Asteroid 1691 Oort Oort Cloud Oort constants of galactic structure ...

See also:

Jan Oort, Jan Oort - A few of Oort's Discoveries, Jan Oort - Honors, Jan Oort - Online exhibition

Read more here: » Jan Oort: Encyclopedia II - Jan Oort - Honors

Several features of Betelgeuse are of particular interest to astronomers. It was one of the first stars to have its diameter measured with a stellar interferometer; the diameter was found to be variable, ranging from 290,000,000 km (180 million miles) to 480,000,000 km (300 million miles). At maximum diameter, the star would extend out beyond the orbit of Mars if placed at the location of the Sun. Though only 15 times more massive than the Sun, it is as much as 40 million times greater in volume; a difference in volume much like a beach ball ...

See also:

Betelgeuse, Betelgeuse - Origin of the name Betelgeuse, Betelgeuse - Distinguishing characteristics, Betelgeuse - References in fiction

Read more here: » Betelgeuse: Encyclopedia II - Betelgeuse - Distinguishing characteristics

The word metre is from the Greek metron (μετρον), "a measure" via the French mètre. Its first recorded usage in English is from 1797. In the 18th century, there were two favoured approaches to the definition of the standard unit of length. One suggested defining the metre as the length of a pendulum with a half-period of one second. The other suggested defining the metre as one ten-millionth of the length of the earth's meridian along a quadrant (one-fourth the polar circumference of the earth). In 1791, th ...

See also:

Metre, Metre - SI prefixes applied to the metre, Metre - Conversions, Metre - History, Metre - Timeline of definition

Read more here: » Metre: Encyclopedia II - Metre - History

The key instrument of nearly all modern observational astronomy is the telescope. This serves the dual purposes of gathering more light so that very faint objects can be observed, and magnifying the image so that small and distant objects can be observed. The optics used in a telescope have very exacting requirements which require great precision in their construction. Typical requirements for grinding and polishing a curved mirror, for example, require the surface to be within a f ...

See also:

Observational astronomy, Observational astronomy - Unaided eye, Observational astronomy - Telescopes, Observational astronomy - Optical telescopes, Observational astronomy - Other instruments, Observational astronomy - Observation tools, Observational astronomy - Observing, Observational astronomy - Related lists

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Space-based observations at the submillimetre wavelengths remove the ground-based limitations of atmospheric absorption. The Submillimeter Wave Astronomy Satellite (SWAS) was launched into low Earth orbit on December 5, 1998 as one of NASA's Small Explorer Program (SMEX) missions. The mission of the spacecraft is to make targeted observations of giant molecular clouds and dark cloud cores. The focus of SWAS is five spectral lines: water (H2O), isotopic water (H218O), isotopic carbon monoxide ...

See also:

Submillimetre astronomy, Submillimetre astronomy - Submillimetre astronomy from the ground, Submillimetre astronomy - Submillimetre astronomy from space

Read more here: » Submillimetre astronomy: Encyclopedia II - Submillimetre astronomy - Submillimetre astronomy from space