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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.
  • 709
  • 11 Oct 2022
Topic Review Video
Black Hole
Black holes are the celestial objects existing at the center of every galaxy. They can currently only be described by their spin, charge, and angular momentum, with other attributes derived from the basic properties. The existence of black holes was first predicted by German physicist and astronomer Karl Schwarzschild in 1916, with the exact solutions to Einstein's field equations of general relativity one year after its publication. Finnish physicist Gunnar Nordström proposed a theory of gravity and electromagnetism with four spatial dimensions in 1914, and later developed into the stationary charged black hole in 1918.
  • 707
  • 15 Oct 2023
Topic Review
Five Hundred Meter Aperture Spherical Telescope
The Five-hundred-meter Aperture Spherical radio Telescope (FAST; Chinese: 五百米口径球面射电望远镜), nicknamed Tianyan (天眼, lit. "Heavenly Eye" or "The Eye of Heaven") is a radio telescope located in the Dawodang depression (大窝凼洼地), a natural basin in Pingtang County, Guizhou Province, southwest China. It consists of a fixed 500 m (1,600 ft) diameter dish constructed in a natural depression in the landscape. It is the world's largest filled-aperture radio telescope, and the second-largest single-dish aperture after the sparsely-filled RATAN-600 in Russia. It has a novel design, using an active surface made of metal panels that can be tilted by a computer to help change the focus to different areas of the sky. The cabin containing the feed antenna suspended on cables above the dish is also moved using a digitally-controlled winch by the computer control system to steer the instrument to receive from different directions. Construction on the FAST project began in 2011 and it achieved first light in September 2016. It is currently undergoing testing and commissioning. It observes at wavelengths of 10 cm to 4.3 m.:11 The telescope made its first discovery of two new pulsars in August 2017, barely one year after its first light. The new pulsars PSR J1859-01 and PSR J1931-02, which are also referred to as FAST pulsar #1 and #2 (FP1 and FP2), were detected on 22 and 25 August and are 16,000 and 4,100 light years away, respectively. They were independently confirmed by the Parkes Observatory in Australia on 10 September. The telescope had discovered 44 new pulsars by September, 2018.
  • 706
  • 14 Oct 2022
Topic Review
PSR J0737-3039
PSR J0737−3039 is the only known double pulsar. It consists of two neutron stars emitting electromagnetic waves in the radio wavelength in a relativistic binary system. The two pulsars are known as PSR J0737−3039A and PSR J0737−3039B. It was discovered in 2003 at Australia's Parkes Observatory by an international team led by the radio astronomer Marta Burgay during a high-latitude pulsar survey.
  • 705
  • 12 Oct 2022
Topic Review
Capricornus
Capricornus, often depicted as a sea-goat in mythology, is a zodiac constellation located in the southern celestial hemisphere. Its name is derived from the Latin words "capra," meaning goat, and "cornu," meaning horn. Capricornus is notable for containing several bright stars and is associated with the winter solstice in the Northern Hemisphere.
  • 702
  • 29 Feb 2024
Topic Review
Draco
Draco, Latin for "the dragon," is a large and distinctive constellation in the northern celestial hemisphere. It is renowned for its winding shape, resembling a serpentine dragon winding around the celestial pole, and is home to several notable deep-sky objects, including the Cat's Eye Nebula and the Draco Dwarf Galaxy.
  • 699
  • 08 Mar 2024
Topic Review
Cancer (Constellation)
Cancer, recognized as one of the twelve zodiac constellations, is situated in the northern celestial hemisphere. Named after the Latin word for crab, Cancer is associated with the Greek myth of the crab sent by Hera to distract Hercules during his battle with the Hydra.
  • 696
  • 29 Feb 2024
Topic Review
Ursa Major Moving Group
The Ursa Major Moving Group, also known as Collinder 285 and the Ursa Major association, is the closest stellar moving group – a set of stars with common velocities in space and thought to have a common origin in space and time. In the case of the Ursa Major group, all the stars formed about 300 million years ago. Its core is located roughly 80 light years away and part of the Local Bubble. It is rich in bright stars including most of the stars of the Big Dipper.
  • 693
  • 14 Oct 2022
Topic Review
Corvus
Corvus, Latin for "crow" or "raven," is a small but distinct constellation visible in the southern celestial hemisphere. Its shape is reminiscent of a bird in flight, featuring four bright stars that form the outline of a celestial crow. In ancient mythology, Corvus is associated with various tales, often depicted as a messenger bird serving the gods.
  • 691
  • 08 Mar 2024
Topic Review
Pisces
Pisces, the Latin term for "fishes," is a sprawling constellation in the northern celestial hemisphere, representing two fish tied together by a cord. Positioned between Aquarius and Aries along the ecliptic, Pisces is rich in mythology and serves as a prominent fixture in both ancient and modern astronomy.
  • 688
  • 15 Mar 2024
Topic Review
List of Messier Objects
The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his "Catalogue des Nébuleuses et des Amas d'Étoiles" ("Catalogue of Nebulae and Star Clusters"). A preliminary version first appeared in Memoirs of the French Academy of Sciences in 1771, and the last item was added in 1966 by Kenneth Glyn Jones, based on Messier's observations. The first version of Messier's catalogue contained 45 objects and was published in 1774 in the journal of the French Academy of Sciences in Paris. In addition to his own discoveries, this version included objects previously observed by other astronomers, with only 17 of the 45 objects being Messier’s. By 1780 the catalog had increased to 80 objects. The final version of the catalogue containing 103 objects was published in 1781 in the Connaissance des Temps for the year 1784. However, due to what was thought for a long time to be the incorrect addition of Messier 102, the total number remained 102. Other astronomers, using side notes in Messier's texts, eventually filled out the list up to 110 objects. The catalogue consists of a diverse range of astronomical objects, ranging from star clusters, nebula and galaxies. Messier 1 is the supernova remnant of Crab Nebula and the great spiral Andromeda Galaxy is M 31. Many further inclusions followed in the next century when the first addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding Messier’s side note in his 1781 edition exemplar of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967. Because Messier was interested in finding only comets, he created a list of non-comet objects that frustrated his hunt for them. The compilation of this list, in collaboration with his assistant Pierre Méchain, is known as the Messier catalogue. This catalogue of objects is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier number.
  • 677
  • 06 Dec 2022
Topic Review
Canis Minor
Canis Minor, Latin for "Lesser Dog," is a small constellation in the northern celestial hemisphere. Named for one of the hunting dogs of Orion in Greek mythology, Canis Minor is characterized by its two brightest stars, Procyon and Gomeisa, which shine brightly in the night sky. 
  • 672
  • 29 Feb 2024
Topic Review
List of Jupiter Trojans (Trojan Camp) (1–100000)
This is a partial list of Jupiter's L5 trojans (60° behind Jupiter) with numbers 1–100000 (also see main page).
  • 666
  • 05 Dec 2022
Topic Review
Camelopardalis
Camelopardalis, recognized by the International Astronomical Union (IAU), is a constellation located in the northern celestial hemisphere. Its name is derived from the Latin word for "giraffe," reflecting its association with this graceful and majestic creature.
  • 662
  • 29 Feb 2024
Topic Review
Andromeda
Andromeda, named after the mythical princess in Greek mythology, is one of the 88 constellations officially recognized by the International Astronomical Union (IAU). Located in the northern celestial hemisphere, Andromeda is renowned for hosting the Andromeda Galaxy (M31), the closest spiral galaxy to our own Milky Way, making it a captivating subject for both amateur stargazers and professional astronomers alike.
  • 657
  • 29 Feb 2024
Topic Review
Aquarius
Aquarius, a constellation of the zodiac, is rich in mythological and astrological significance. Representing the Water Bearer in ancient Greek mythology, Aquarius is celebrated for its association with the nurturing and life-giving element of water. Positioned along the celestial equator, this constellation captivates observers with its diverse array of celestial objects and its prominent role in the astrological tradition.
  • 655
  • 29 Feb 2024
Topic Review
Transit of Venus, 1639
The first known observations and recording of a transit of Venus were made in 1639 by the English astronomers Jeremiah Horrocks and his friend and correspondent William Crabtree. The pair made their observations independently on 4 December that year (24 November under the Julian calendar then used in England); Horrocks from Carr House, then in the village of Much Hoole, Lancashire, and Crabtree from his home in Broughton, near Manchester. The friends, followers of the new astronomy of Johannes Kepler, were self-taught mathematical astronomers who had worked methodically to correct and improve Kepler's Rudolphine tables by observation and measurement. In 1639, Horrocks was the only astronomer to realise that a transit of Venus was imminent; others became aware of it only after the event when Horrocks's report of it was circulated. Although the friends both died within five years of making their observations, their ground-breaking work was influential in establishing the size of the Solar System; for this and their other achievements Horrocks and Crabtree, along with their correspondent William Gascoigne, are considered to be the founding fathers of British research astronomy.
  • 654
  • 06 Dec 2022
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.
  • 647
  • 18 Oct 2022
Topic Review
Vallis (Planetary Geology)
Vallis or valles /ˈvælɪs/ (plural valles /ˈvæliːz/) is the Latin word for valley. It is used in planetary geology to name landform features on other planets. Scientists used vallis for old river valleys they discovered when they sent the first probes to Mars. The Viking Orbiters caused a revolution in our ideas about water on Mars; finding huge river valleys in many areas. Space craft cameras showed that floods of water broke through dams, carved deep valleys, eroded grooves into bedrock, and traveled thousands of kilometers. Some valles on Mars (Mangala Vallis, Athabasca Vallis, Granicus Vallis, and Tinjar Valles) clearly begin at graben. On the other hand, some of the large outflow channels begin in rubble-filled low areas, called chaos or chaotic terrain. It has been suggested that massive amounts of water were trapped under pressure beneath a thick cryosphere (layer of frozen ground), then the water was suddenly released, perhaps when the cryosphere was broken by a fault.
  • 639
  • 23 Nov 2022
Topic Review
Large Strategic Science Missions
NASA's Large Strategic Science Missions, formerly known as Flagship missions or Flagship-class missions, are the costliest and most capable NASA science spacecraft. Flagship missions exist within all four divisions of NASA's Science Mission Directorate: the astrophysics, Earth science, heliophysics and planetary science divisions. "Large" refers to the budget of each mission, typically the most expensive mission in the scientific discipline. Within the Astrophysics Division and the Planetary Science Division, the large strategic missions are usually in excess of $1 billion. Within Earth Science Division and Heliophysics Division, the large strategic missions are usually in excess of $500 million. "Strategic" refers to their role advancing multiple strategic priorities set forth in plans such as the Decadal Surveys. "Science" marks these missions as primarily scientific in nature, under the Science Mission Directorate (SMD), as opposed to, e.g., human exploration missions under the Human Exploration and Operations Mission Directorate (HEOMD). The lines can be blurred, as when the Lunar Reconnaissance Orbiter began as a directed mission from the HEOMD, and was later transferred to the SMD. Flagship missions are not under the purview of any larger "Flagship Program", unlike, e.g., Discovery-class missions that are under the purview of the Discovery Program. Unlike these competed classes that tender proposals through a competitive selection process, the development of Flagship missions is directed to a specific institution — usually a NASA center or the Jet Propulsion Laboratory — by the Science Mission Directorate. Flagship missions are developed ad-hoc, with no predetermined launch cadence or uniform budget size. Flagship missions are always Class A missions: high priority, very low risk.
  • 633
  • 17 Nov 2022
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