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Gas Giants
A gas giant is a giant planet composed mainly of hydrogen and helium. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet". However, in the 1990s, it became known that Uranus and Neptune are a distinct class of giant planets composed mainly of heavier volatile substances (referred to as "Volatile (astrogeology)#Planetary science, ices"). For this reason, Uranus and Neptune are often classified in the separate category of ice giants. Jupiter and Saturn consist mostly of hydrogen and helium, with heavier elements making up between 3 and 13 percent of their mass.The Interior of Jupiter, Guillot et al., in ''Jupiter: The Planet, Satellites and Magnetosphere'', Bagenal et al., editors, Cambridge University Press, 2004 They are thought to have an outer layer of compressed molecular hydrogen surrounding a layer of liquid metallic hydrogen, with a molten rocky core inside. The outermost portion of their hydrogen atmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined and slightly less than one-thousandth the mass of the Sun. Its diameter is 11 times that of Earth and a tenth that of the Sun. Jupiter orbits the Sun at a distance of , with an orbital period of . It is the List of brightest natural objects in the sky, third-brightest natural object in the Earth's night sky, after the Moon and Venus, and has been observed since prehistoric times. Its name derives from that of Jupiter (god), Jupiter, the chief deity of ancient Roman religion. Jupiter was the first of the Sun's planets to form, and its inward migration during the primordial phase of the Solar System affected much of the formation history of the other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics Today
''Physics Today'' is the membership magazine of the American Institute of Physics. First published in May 1948, it is issued on a monthly schedule, and is provided to the members of ten physics societies, including the American Physical Society. It is also available to non-members as a paid annual subscription. The magazine informs readers about important developments in overview articles written by experts, shorter review articles written internally by staff, and also discusses issues and events of importance to the science community in politics, education, and other fields. The magazine provides a historical resource of events associated with physics. For example it discussed debunking the physics of the Star Wars program of the 1980s, and the state of physics in China and the Soviet Union during the 1950s and 1970s. According to the ''Journal Citation Reports'', the journal has a 2017 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic jou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Red Spot
The Great Red Spot is a persistent high-pressure area, high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm that is the largest in the Solar System. It is the most recognizable feature on Jupiter, owing to its red-orange color whose origin is still unknown. Located 22 Degree (angle), degrees south of Jupiter's equator, it produces wind-speeds up to . It was first observed in September 1831, with 60 recorded observations between then and 1878, when continuous observations began. A similar spot was observed from 1665 to 1713; if this is the same storm, it has existed for at least years, but a study from 2024 suggests this is not the case. Observation history First observations The Great Red Spot may have existed before 1665, but it could be that the present spot was first seen only in 1830, and was well studied only after a prominent appearance in 1879. The storm that was seen in the 17th century may have been different from the storm that exists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler-138d
Kepler-138, also known as KOI-314, is a red dwarf located in the constellation Lyra, 219 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets transiting their stars. The star hosts three confirmed planets and a likely fourth, including the lowest-mass exoplanet with a measured mass and size discovered to date, Kepler-138b, with a mass comparable to that of Mars. Kepler-138d is remarkable for its low density; initially thought likely to be a gas dwarf, more recent observations as of 2022 show that it, as well as planet c, are likely to be ocean worlds. Nomenclature and history Prior to Kepler observation, KOI-314 had the 2MASS catalogue number 2MASS J19213157+4317347. In the Kepler Input Catalog it has the designation of KIC 7603200, and when it was found to have transiting planet candidates it was given the Kepler object of interest number of KOI-314. Planetar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrodynamic Escape
In atmospheric science, hydrodynamic escape refers to a thermal atmospheric escape mechanism that can lead to the escape of heavier atoms of a planetary atmosphere through numerous collisions with lighter atoms, typically hydrogen. This mechanism may explain why some planetary atmospheres are depleted in oxygen, nitrogen, and heavier noble gases, such as xenon. Description Particles in the atmosphere need to achieve sufficiently high velocity (higher than the escape velocity) to escape from the planetary gravity field. There are different ways to achieve this velocity. Those processes in which the high velocity is related to the temperature are called thermal escape. The root mean square thermal velocity () of an atomic species is v_\mathrm = \sqrt where is the Boltzmann constant, is the temperature, and is the mass of the species. Lighter molecules or atoms will therefore be moving faster than heavier molecules or atoms at the same temperature. Thus they are easier to es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin–Helmholtz Mechanism
The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools. The cooling causes the internal pressure to drop, and the star or planet shrinks as a result. This compression, in turn, heats the core of the star/planet. This mechanism is evident on Jupiter and Saturn and on brown dwarfs whose central temperatures are not high enough to undergo hydrogen fusion. It is estimated that Jupiter radiates more energy through this mechanism than it receives from the Sun, but Saturn might not. Jupiter has been estimated to shrink at a rate of approximately 1 mm/year by this process, corresponding to an internal flux of 7.485 W/m2. The mechanism was originally proposed by Kelvin and Helmholtz in the late nineteenth century to explain the source of energy of the Sun. By the mid-nineteenth century, conservation of energy had been accepted, and one consequence of this law of physics is that the Sun must have some energy source to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degenerate Matter
Degenerate matter occurs when the Pauli exclusion principle significantly alters a state of matter at low temperature. The term is used in astrophysics to refer to dense stellar objects such as white dwarfs and neutron stars, where thermal pressure alone is not enough to prevent gravitational collapse. The term also applies to metals in the Fermi gas approximation. Degenerate matter is usually modelled as an ideal Fermi gas, an ensemble of non-interacting fermions. In a quantum mechanical description, particles limited to a finite volume may take only a discrete set of energies, called quantum states. The Pauli exclusion principle prevents identical fermions from occupying the same quantum state. At lowest total energy (when the thermal energy of the particles is negligible), all the lowest energy quantum states are filled. This state is referred to as full degeneracy. This degeneracy pressure remains non-zero even at absolute zero temperature.see http://apod.nasa.gov/apod/ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravity
In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force between objects and the Earth. This force is dominated by the combined gravitational interactions of particles but also includes effect of the Earth's rotation. Gravity gives weight to physical objects and is essential to understanding the mechanisms responsible for surface water waves and lunar tides. Gravity also has many important biological functions, helping to guide the growth of plants through the process of gravitropism and influencing the circulation of fluids in multicellular organisms. The gravitational attraction between primordial hydrogen and clumps of dark matter in the early universe caused the hydrogen gas to coalesce, eventually condensing and fusing to form stars. At larger scales this results in galaxies and clust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artist Impression Of Ultra Fluffy Gas Giant Planet Orbiting A Red Dwarf Star
An artist is a person engaged in an activity related to creating art, practicing the arts, or demonstrating the work of art. The most common usage (in both everyday speech and academic discourse) refers to a practitioner in the visual arts only. However, the term is also often used in the entertainment business to refer to actors, musicians, singers, dancers and other performers, in which they are known as ''Artiste'' instead. ''Artiste'' (French) is a variant used in English in this context, but this use has become rare. The use of the term "artist" to describe writers is valid, but less common, and mostly restricted to contexts such as critics' reviews; "author" is generally used instead. Dictionary definitions The ''Oxford English Dictionary'' defines the older, broader meanings of the word "artist": * A learned person or Master of Arts * One who pursues a practical science, traditionally medicine, astrology, alchemy, chemistry * A follower of a pursuit in which skill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Jupiter
Hot Jupiters (sometimes called hot Saturns) are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter (i.e. Jupiter analogue, Jupiter analogues) but that have very short orbital periods (). The close proximity to their stars and high surface-atmosphere temperatures resulted in their informal name "hot Jupiters". Hot Jupiters are the easiest extrasolar planets to detect via the radial velocity, radial-velocity method, because the oscillations they induce in their parent stars' motion are relatively large and rapid compared to those of other known types of planets. One of the best-known hot Jupiters is . Discovered in 1995, it was the first extrasolar planet found orbiting a Sun-like star. has an orbital period of about four days. General characteristics Though there is diversity among hot Jupiters, they do share some common properties. * Their defining characteristics are their large masses and short orbital periods, spanning 0.36–11.8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Of Matter
In the physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The glass of the jar is a different material, in its own separate phase. (See .) More precisely, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, magnetization and chemical composition. The term ''phase'' is sometimes used as a synonym for state of matter, but there can be several immiscible phases of the same state of matter (as where oil and water separate into distinct phases, both in the liquid state). Types of phases Distinct phases may be described as different states of matter such as gas, liquid, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
