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Topic Review
Perturbation
In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massive body. The other forces can include a third (fourth, fifth, etc.) body, resistance, as from an atmosphere, and the off-center attraction of an oblate or otherwise misshapen body.
  • 1.3K
  • 28 Oct 2022
Topic Review
April 17: Apollo 13 Returns Safely
Apollo 13 was a 1970 NASA Moon mission that turned into a survival crisis after an oxygen tank explosion. The crew, aided by Mission Control, used the Lunar Module as a lifeboat and improvised fixes to return safely. Though the Moon landing was canceled, the mission became a landmark example of problem-solving under pressure.
  • 1.2K
  • 17 Apr 2025
Topic Review
List of 19th-Century Lunar Eclipses
See also: List of lunar eclipses, List of 18th-century lunar eclipses, and List of 20th-century lunar eclipses
  • 1.2K
  • 25 Oct 2022
Topic Review
Coma Berenices
Coma Berenices, Latin for "Berenice's Hair," is a constellation in the northern celestial hemisphere. Named after the ancient Egyptian queen Berenice II, it is renowned for its distinctive asterism resembling a flowing mane of hair. Coma Berenices contains several notable celestial objects, including the Coma Cluster of galaxies.
  • 1.2K
  • 08 Mar 2024
Topic Review
The Crab Nebula in Gamma-Rays
The Crab nebula is one of the best studied objects in the sky, second only to the Sun. It is the remnant of a supernova explosion occurred in A. D. 1054, and it represents the prototype of an entire class of supernova remnants: Pulsar Wind Nebulae. It consists of two different bright non-thermal sources — the pulsar and the nebula. Both objects have played a key role in the development of high-energy astrophysics. Thanks to their bright emission at all wavelengths, they have been observed by virtually all new astronomical instruments and have been at the origin of a wealth of important scientific discoveries.
  • 1.2K
  • 13 Jan 2022
Topic Review
Lunar Regolith Penetrating Radar
An extraordinary component of this mission is the “Lunar Regolith Penetrating Radar” (LRPR) housed within its lander, which currently stands as the most advanced payload in terms of vertical resolution among all penetrating radars employed in lunar exploration.
  • 1.2K
  • 10 Nov 2023
Topic Review
Soyuz TM-23
Soyuz TM-23 was a Soyuz spaceflight which launched on February 21, 1996, to Mir. The spacecraft launched from Baikonur Cosmodrome, and after two days of flight, Yuri Onufrienko and Yury Usachov docked with Mir and became the 21st resident crew of the Station. On September 2, 1996, after 191 days docked with Mir, the ship undocked with the launch crew and Claudie André-Deshays onboard, before eventually landing 107 km (66 mi) south west of Akmola, Kazakhstan.
  • 1.2K
  • 28 Nov 2022
Topic Review
Fornax
Fornax, Latin for "furnace," is a small and faint constellation located in the southern celestial hemisphere. Despite its modest size, Fornax is home to several notable deep-sky objects, including the Fornax Cluster of galaxies. French astronomer Nicolas Louis de Lacaille bestowed the name "Fornax" upon this constellation in 1756, and it is now recognized as one of the 88 modern constellations.
  • 1.2K
  • 15 Mar 2024
Topic Review
Controlled Impact Demonstration
The Controlled Impact Demonstration (or colloquially the Crash In the Desert) was a joint project between NASA and the Federal Aviation Administration (FAA) that intentionally crashed a remotely controlled Boeing 720 aircraft to acquire data and test new technologies to aid passenger and crew survival. The crash required more than four years of preparation by NASA Ames Research Center, Langley Research Center, Dryden Flight Research Center, the FAA, and General Electric. After numerous test runs, the plane was crashed on December 1, 1984. The test went generally according to plan, and produced a spectacular fireball that required more than an hour to extinguish. The FAA concluded that about one-quarter of the passengers would have survived, that the antimisting kerosene test fuel did not sufficiently reduce the risk of fire, and that several changes to equipment in the passenger compartment of aircraft were needed. NASA concluded that a head-up display and microwave landing system would have helped the pilot more safely fly the aircraft.
  • 1.2K
  • 18 Oct 2022
Topic Review
Nemesis
Nemesis is a hypothesized companion object orbiting the Sun, motivated by the claim of a terrestrial extinction periodicity. Astronomer Percival Lowell in 1915 thought that some glitches in the orbit of Uranus might be caused by what he dubbed Planet X, and led to the discovery of Pluto in 1930. The existence of the object beyond Pluto may be able to explain the architecture of the Edgeworth–Kuiper Belt and a secular perihelion precession of Saturn. The Nemesis hypothesis has also been used to explain the measurements of the ages of 155 lunar spherules from the Apollo 14 site.
  • 1.1K
  • 14 Jan 2024
Topic Review
MOST (Satellite)
The Microvariability and Oscillations of Stars telescope, better known simply as MOST, was Canada 's first space telescope. Up until nearly 10 years after its launch it was also the smallest space telescope in orbit (for which its creators nicknamed it the "Humble Space Telescope", in reference to one of the largest, the Hubble). MOST was the first spacecraft dedicated to the study of asteroseismology, subsequently followed by the now-completed CoRoT and Kepler missions. It was also the first Canadian science satellite launched since ISIS II, 32 years previously.
  • 1.1K
  • 02 Nov 2022
Topic Review
The Kottler-Schwarzschild-Kiselev Spacetimes
The Kottler-Schwarzschild-Kiselev blackhole spacetimes are analytically studied. The instances of the gtt components of the metric tensor are considered, where it contains a linear term, a cosmological constant, and both a linear term and a cosmological constant, in the deSitter determination and in the anti-deSitter one. The Birkhoff theorem is proven to be obeyed. The infinite-redshift surfaces are written. The parameter space of the models which constrain the blackhole mass are analytically spelled out. The coordinate-singularity-avoiding coordinates transformations are newly found. The possibility to obtain a scheme geometrically-mimicking quintessence is ruled out. The weak-field limit is studied from the appropriate Christoffel symbol. The quantum regime is envisaged.
  • 1.1K
  • 11 Nov 2024
Topic Review
Hydrus (Constellation)
Hydrus is a small and faint constellation in the southern celestial hemisphere. It is named after the Latin word for "male water snake" and is often depicted as a water snake winding its way through the southern skies. 
  • 1.1K
  • 15 Mar 2024
Topic Review
Soyuz 4
Soyuz 4 (Russian: Союз 4, Union 4) was launched on 14 January 1969, carrying cosmonaut Vladimir Shatalov on his first flight. The aim of the mission was to dock with Soyuz 5, transfer two crew members from that spacecraft, and return to Earth. The previous Soyuz flight (Soyuz 3) was also a docking attempt but failed for various reasons. The radio call sign of the crew was Amur, while Soyuz 5 was Baikal. This referred to the trans-Siberian railway project called the Baikal-Amur Mainline, which was in development at the time.
  • 1.1K
  • 03 Nov 2022
Topic Review
Historical Solar Eclipses and Implications in Celestial Mechanics
Solar and lunar eclipses are indeed the first astronomical phenomena which have been recorded since very early antiquity. Their periodicities gave birth to the first luni-solar calendars based on the Methonic cycle since the sixth century before Christ. 
  • 1.1K
  • 23 Feb 2024
Topic Review
Soyuz TM-22
Soyuz TM-22 was a Soyuz spaceflight to the Soviet space station Mir. It launched from Baikonur Cosmodrome Launch Pad 1 on September 3, 1995. After two days of free flight, the crew docked with Mir to become Mir Principal Expedition 20 and Euromir 95. Mir 20 was a harbinger of the multinational missions that would be typical of the International Space Station. After 179 days, 1 hour and 42 minutes on orbit, Reiter obtained the record for spaceflight duration by a Western European.
  • 1.1K
  • 11 Oct 2022
Biography
Padma Kant Shukla
Padma Kant Shukla (CorrFRSE, FInstP, FAPS, AFTWAS) (7 July 1950 – 26 January 2013) was a Distinguished Professor and first International Chair of the Physics and Astronomy Department of Ruhr-University Bochum (RUB) in Germany.[1] He was also the Director of the International Centre for Advanced Studies in Physical Sciences at RUB. He held a Ph.D. in Physics from Banaras Hindu University (BHU)
  • 1.1K
  • 30 Nov 2022
Topic Review
Circinus
Circinus is a small, faint constellation located in the southern sky. Named after the Latin word for compass, it was first introduced in the 18th century by the French astronomer Nicolas Louis de Lacaille during his observations of the southern hemisphere. Despite its modest size, Circinus harbors several intriguing celestial objects, including a notable planetary nebula and multiple star systems of scientific interest.
  • 1.0K
  • 08 Mar 2024
Topic Review
Cosmology Can Serve to Determine Neutrino's Properties
Neutrino particles have been found, due to their non-interacting, almost-vanishing mass, and relativistic nature, as being suitable to hold roles in many phenomena in nature, which have made them attract a large interest among the scientific community. In particular, on the cosmological level, the neutrino is one of the few components whose contribution to the Universe energy budget changes with its expansion, from being part of the radiation to that of the matter density, with implications on the expansion of the background or the growth of large-scale structures. It has also the feature of being abundantly present since the Universe’s early beginning, participating by then to the different phases of its evolution, which allows us to constrain its main properties such as its mass and number of species by any of the known cosmological observables.
  • 1.0K
  • 27 May 2022
Topic Review
2020 AV2
2020 AV2 is a near-Earth asteroid discovered by the Zwicky Transient Facility on 4 January 2020. It is the first asteroid discovered to have an orbit completely within Venus's orbit, and is thus the first and only known member of the inner-Venusian Vatira population of Atira-class asteroids. 2020 AV2 has the smallest known aphelion and third-smallest known semi-major axis among all asteroids. With an absolute magnitude around 16.4, the asteroid is expected to be larger than 1 km in diameter.
  • 1.0K
  • 25 Nov 2022
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