Search | Encyclopedia MDPI

You're using an outdated browser. Please upgrade to a modern browser for the best experience.

Subject:

Sort by:

Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)

Filter:

All Topic Review Biography Peer Reviewed Entry Video Entry

Topic Review

(225088) 2007 OR10

(225088) 2007 OR10, proposed to be named Gonggong, is a likely dwarf planet in the Solar System beyond Neptune, and is a member of the scattered disc. It has a highly eccentric and inclined orbit during which it ranges from 33–101 astronomical units (4.9–15.1 billion kilometers) from the Sun. (As of 2019), its distance from the Sun is 88 AU (1.32×1010 km; 8.2×109 mi), and it is the sixth-farthest known Solar System object. 2007 OR10 is in a 3:10 orbital resonance with Neptune, in which it completes three orbits around the Sun for every ten orbits completed by Neptune. 2007 OR10 was discovered in July 2007 by American astronomers Megan Schwamb, Michael Brown, and David Rabinowitz at the Palomar Observatory, and the discovery was announced in January 2009. At 1,230 km (760 mi) in diameter, 2007 OR10 is approximately the size of Pluto's moon Charon, and is the fifth-largest known trans-Neptunian object in the Solar System. It is sufficiently massive to be gravitationally rounded, thereby qualifying for dwarf planet status. Its large mass also makes retention of a tenuous atmosphere of methane just possible, though such an atmosphere would slowly escape into space. 2007 OR10 is currently the largest known body in the Solar System without an official name, but in 2019, the discoverers hosted an online poll for the general public to help choose a name for the object, and the name Gonggong won. The winning name is derived from Gonggong, a Chinese water god responsible for chaos, floods and the tilt of the Earth. 2007 OR10 is red in color, likely due to the presence of organic compounds called tholins on its surface. Water ice is also present on its surface, which hints at a brief period of cryovolcanic activity in the distant past. 2007 OR10 rotates slowly compared to other trans-Neptunian objects, which typically have rotation periods less than 12 hours, which may be due to its natural satellite, provisionally designated S/2010 (225088) 1.

4.5K
02 Dec 2022

Topic Review

Nuclear Symmetry Energy

Nuclear symmetry energy is a measure of the energy cost to make nuclear systems more neutron rich. It depends on the density of the system. Information about the density dependence of nuclear symmetry energy has broad ramifications on the mechanisms of supernova explosions, properties of neutron stars and gravitational waves from their mergers. It is also important for understanding properties of nuclei as well as the dynamics and products of their collisions in laboratory experiments.

4.4K
03 Aug 2021

Topic Review

White holes are regions of space-time that although matter may come out, no matter is able to enter; or in other words, they have gravitational features opposite to those of black holes. White holes exist in the solutions to Einstein's general theory of relativity and the maximal extension of the Schwarzschild metric. The term "white hole" was coined by Soviet cosmologist Igor Novikov in 1965 after his theorization on the existence.

4.0K
15 Oct 2023

Topic Review

Cygnus, known as the Swan, is a prominent constellation in the northern celestial hemisphere. Its distinctive shape resembles a flying bird with outstretched wings, earning it the nickname "the Northern Cross." Cygnus is rich in celestial wonders, including the famous binary star system Albireo, the North America Nebula, and the Veil Nebula complex.

4.0K
08 Mar 2024

Topic Review

Ursa Major, often referred to as the Great Bear, is one of the most recognizable and prominent constellations in the northern celestial hemisphere. Its distinctive shape, resembling a large bear with a long tail, has captivated human imagination for millennia. At the heart of Ursa Major lies the Big Dipper, a prominent asterism formed by seven bright stars that serve as a navigational guide and cultural icon across cultures and civilizations.

3.9K
15 Mar 2024

Topic Review

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.

3.9K
08 Mar 2024

Topic Review

Exoplanetology, or exoplanetary science, is an integrated field of astronomical science dedicated to the search for and study of exoplanets (extrasolar planets). It employs an interdisciplinary approach which includes astrobiology, astrophysics, astronomy, astrochemistry, astrogeology, geochemistry, and planetary science.

3.9K
09 Nov 2022

Topic Review

88 Modern Constellations

In contemporary astronomy, the sky is divided into 88 regions called constellations, generally based on the asterisms (which are also called "constellations") of Greek and Roman mythology. The number of 88, along with the contemporary scientific notion of "constellation", was conventioned in 1922 by the International Astronomical Union in order to establish a universal pattern for professional astronomers, who defined constellations from then on as regions of the sky separated by arcs of right ascensions and declinations and grouped by asterisms of their historically most important stars, which cover the entire celestial sphere. The constellations along the ecliptic are called the zodiac. The ancient Sumerians, and later the Greeks (as recorded by Ptolemy), established most of the northern constellations in international use today. When explorers mapped the stars of the southern skies, European and American astronomers proposed new constellations for that region, as well as ones to fill gaps between the traditional constellations. Not all of these proposals caught on, but in 1922, the International Astronomical Union (IAU) adopted the modern list of 88 constellations. After this, Eugène Joseph Delporte drew up precise boundaries for each constellation, so that every point in the sky belonged to exactly one constellation.

3.7K
08 Oct 2022

Topic Review

Lyra is a constellation in the northern celestial hemisphere known for its prominent star Vega, one of the brightest stars in the sky. Represented as a lyre, a musical instrument from Greek mythology, Lyra is rich in celestial objects. Lyra is bordered by Vulpecula to the south, Hercules to the west, Draco to the north, and Cygnus to the east.

3.7K
15 Mar 2024

Biography

Albert Einstein

Albert Einstein, born on March 14, 1879, in Ulm, Germany, is widely regarded as one of the most brilliant scientists in human history. His groundbreaking contributions to physics revolutionized our understanding of the universe and earned him worldwide acclaim. Einstein's life and work remain a source of inspiration and fascination, making him an iconic figure in the realm of science and beyond

3.5K
21 Feb 2024

Topic Review

Canis Major, Latin for "Greater Dog," is one of the most prominent constellations in the southern celestial hemisphere. Often depicted as one of Orion's hunting dogs in Greek mythology, Canis Major is best known for its brightest star, Sirius, also called the Dog Star, which is the brightest star in the night sky. With its distinctive shape and rich cultural significance, Canis Major has fascinated astronomers and storytellers throughout history.

3.4K
29 Feb 2024

Topic Review

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.

3.3K
08 Mar 2024

Topic Review

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.

3.2K
15 Mar 2024

Topic Review

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.

3.2K
29 Feb 2024

Topic Review

Soyuz 11 (Russian: Союз 11, lit. 'Union 11') was the only crewed mission to board the world's first space station, Salyut 1 (Soyuz 10 had soft-docked, but had not been able to enter due to latching problems). The crew, Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, arrived at the space station on 7 June 1971, and departed on 29 June 1971. The mission ended in disaster when the crew capsule depressurised during preparations for re-entry, killing the three-man crew. The three crew members of Soyuz 11 are the only humans to have died in space.

3.1K
09 Oct 2022

Topic Review

Planet-Hosting Stars

Planet-hosting stars are stars which host planets, therefore forming planetary systems. This article describes the correlations between stars' characteristics and the characteristics of the planets that orbit them, and other connections between stars and their planets.

3.0K
23 Nov 2022

Topic Review

An asterism is an observed pattern or group of stars in the sky. Asterisms can be any identified pattern or group of stars, and therefore are a more general concept than the formally defined 88 constellations. Constellations are based on asterisms, but unlike asterisms, constellations outline and today completely divide the sky and all its celestial objects into regions around their central asterisms. For example, the asterism known as the Big Dipper comprises the seven brightest stars in the constellation Ursa Major. Another is the asterism of the Southern Cross, within the constellation of Crux. Asterisms range from simple shapes of just a few stars to more complex collections of many stars covering large portions of the sky. The stars themselves may be bright naked-eye objects or fainter, even telescopic, but they are generally all of a similar brightness to each other. The larger brighter asterisms are useful for people who are familiarizing themselves with the night sky. The patterns of stars seen in asterisms are not necessarily a product of any physical association between the stars, but are rather the result of the particular perspectives of their observations. For example the Summer Triangle is a purely observational physically unrelated group of stars, but the stars of Orion's Belt are all members of the Orion OB1 association and five of the seven stars of the Big Dipper are members of the Ursa Major Moving Group. Physical associations, such as the Hyades or Pleiades, can be asterisms in their own right and part of other asterism at the same time.

3.0K
29 Nov 2022

Topic Review

Virgo is one of the 12 constellations of the zodiac, located between Leo to the west and Libra to the east. Covering a vast area of the sky, Virgo is the second-largest constellation after Hydra. Represented as a maiden holding a sheaf of wheat, Virgo is often associated with fertility and agriculture in ancient mythology. This constellation is notable for hosting the bright star Spica, which serves as a celestial marker for navigation and observation.

3.0K
15 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.

3.0K
29 Feb 2024

Topic Review

Mars is the fourth planet from the Sun in our solar system and is named after Mars, the Roman god of war. Mars is also known as the "Red Planet" due to its reddish appearance when seen from Earth. The prefix areo-, from the Greek god of war, Ares, refers to Mars in the same way geo- refers to Earth. Until the first flyby of Mars by Mariner 4 in 1965, it was thought that Mars had channels of liquid water. Observations later showed that these channels do not exist. Still, of all the planets in our solar system other than Earth, Mars is the most likely to harbor liquid water, and perhaps life. Its rotational period and seasonal cycles are also similar to those of the Earth. It has the highest mountain in the solar system, Olympus Mons, the largest canyon in the solar system, Valles Marineris, and polar ice caps. Mars has two moons, Phobos and Deimos, which are small and oddly-shaped. These may be captured asteroids similar to 5261 Eureka, a Mars trojan asteroid. Mars can be seen from Earth by the naked eye. Its apparent magnitude reaches -2.9, a brightness surpassed only by Venus, the Moon, and the Sun. For much of the year, Jupiter may appear brighter to the naked eye than Mars. Mars is currently host to four orbiting spacecraft, more than any planet other than Earth. It is also home to the two Mars Exploration Rovers, Spirit and Opportunity.

2.9K
21 Nov 2022

Page
of
13

Featured Entry Collections

>>

Featured Books

>>

Encyclopedia of COVID-19

Encyclopedia of Engineering

Encyclopedia of Social Sciences

Encyclopedia of Social Sciences
Chief Editor: Kum Fai Yuen

Encyclopedia of Digital Society, Industry 5.0 and Smart City

Encyclopedia of Digital Society, Industry 5.0 and Smart City
Chief Editor: Sandro Serpa

Academic Video Service

Feedback

Top