Internal structure of the MoonHaving a mean density of 3,346.4 kg/m, the Moon is a differentiated body, being composed of a geochemically distinct crust, mantle, and planetary core. This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4.5 billion years ago.
Mercury (planet)Mercury is the first planet from the Sun and the smallest in the Solar System. It is a rocky planet with a trace atmosphere and a surface gravity slightly lower than that of Mars. The surface of Mercury is similar to Earth's Moon, being cratered, with an expansive rupes system generated from thrust faults, and bright ray systems, formed by ejecta.
Accretion (astrophysics)In astrophysics, accretion is the accumulation of matter into a massive object by gravitationally attracting more matter. If the matter is gaseous the result is an accretion disc. Accretion of solid matter such as dust will form larger solid objects. Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.
Solar SystemThe Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The Solar System is an isolated single-star planetary system (not part of a larger star system) within the Milky Way Galaxy. The system formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, creating the Sun and a protoplanetary disc from which the orbiting bodies assembled.
PlanetA planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets by the most restrictive definition of the term: the terrestrial planets Mercury, Venus, Earth, and Mars, and the giant planets Jupiter, Saturn, Uranus, and Neptune.
JupiterFifth planet from the SunApparent magnitude−2.94 to −1.66Absolute magnitude (H)−9.4Angular diameter29.8" to 50.1"AtmosphereSurface pressure200–600 kPa (30–90 psi)(opaque cloud deck)Scale height27 km (17 mi)Composition by volume89%±2.0%hydrogen10%±2.0%helium0.3%±0.1%methane0.026%±0.004%ammonia0.0028%±0.001%hydrogen deuteride0.0006%±0.0002%ethane0.0004%±0.0004%waterJupiter is the fifth planet from the Sun, and the largest in the Solar System.
MoonNatural satellite orbiting EarthSurface absorbed doserate13.2 μGy/h(during lunar daytime)Surface equivalent doserate57.0 μSv/h(during lunar daytime)Apparent magnitude−2.5 to −12.9−12.74 (mean full moon)Absolute magnitude (H)0.2Angular diameter29.3 to 34.1 arcminutesAtmosphereSurface pressure10 Pa (1 picobar) (day)10 Pa (1 femtobar) (night)Composition by volumeHeArNeNaKHThe Moon is the only natural satellite of Earth.
ExoplanetAn exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first detected in 1988, was confirmed in 2003. In 2016, it was recognized that the first possible evidence of an exoplanet had been noted in 1917, a precovery.
HD 149026 bHD 149026 b, also known as Smertrios, is an exoplanet, specifically a hot Jupiter, approximately 250 light-years from the Sun in the constellation of Hercules. Its host star is HD 149026, also named Ogma .
Gas giantA gas giant is a giant planet composed mainly of hydrogen and helium. There are two gas giants in the Solar System: Jupiter and Saturn. The term "gas giant" was originally synonymous with "giant planet". However, starting in the 1970s and continuing into the 1980s, it became increasingly common to classify Uranus and Neptune separately as ice giants, a distinct class of giant planets composed mainly of heavier volatile substances (referred to as "ices").Metallic hydrogenMetallic hydrogen is a phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in 1935 on theoretical grounds by Eugene Wigner and Hillard Bell Huntington. At high pressure and temperatures, metallic hydrogen can exist as a partial liquid rather than a solid. It is thought to appear in large quantities in the hot and gravitationally compressed interiors of Jupiter and Saturn, as well as in some exoplanets.
SeismologySeismology (; from Ancient Greek σεισμός (seismós), meaning 'earthquake', and -λογία (-logía), meaning 'study of') is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic waves through planetary bodies.*As an Amazon Associate I earn from qualifying purchases.