Planetary science (rarely planetology) is the scientific study of planets (including Earth), moons, and planetary systems, in particular those of the Solar System and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation, interrelations and history. It is a strongly interdisciplinary field, originally growing from astronomy and earth science, but which now incorporates many disciplines, including planetary astronomy, planetary geology (together with geochemistry and geophysics), atmospheric science, oceanography, hydrology, theoretical planetary science, glaciology, and exoplanetology. Allied disciplines include space physics, when concerned with the effects of the Sun on the bodies of the Solar System, and astrobiology. There are interrelated observational and theoretical branches of planetary science. History Disciplines Planetary astronomy Geomorphology
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AstrophysicsAstrophysics (from Greek astron, ἄστρον "star", and physis, φύσις "nature") is the branch of astronomy that deals with the physics of the universe, especially with "the nature of the heavenly bodies, rather than their positions or motions in space." Among the objects studied are galaxies, stars, planets, extrasolar planets, the interstellar medium and the cosmic microwave background. Their emissions are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics. In practice, modern astronomical research often involves a substantial amount of work in the realm(s) of theoretical and/or observational physics.
Rich exoplanet system discovered24 August 2010Last updated at 14:03 By Victoria Gill Science reporter, BBC News The researchers say the finding marks a new phase in the hunt for exoplanets Astronomers have discovered a planetary system containing at least five planets that orbit a star called HD 10180, which is much like our own Sun. The star is 127 light years away, in the southern constellation of Hydrus. The researchers used the European Southern Observatory (Eso) to monitor light emitted from the system and identify and characterise the planets. They say this is the "richest" system of exoplanets - planets outside our own Solar System - ever found. Christophe Lovis from Geneva University's observatory in Switzerland was lead researcher on the study. The discovery could provide insight into the formation of our own Solar System "This also highlights the fact that we are now entering a new era in exoplanet research - the study of complex planetary systems and not just of individual planets," he said. “Start Quote
Astronomers may have just discovered the first known free-floating planetThere isn't any reason this object wouldn't or couldn't have satellites of its own; and probably does. Earth has 1-6 moons at any given time, but we don't really notice them because they're small and interloping. Here, experiment: Sadly there is no way to intelligently answer those questions at this time beyond "Well, we do not know of any reason either of those things should be impossible, but we do not know anything about what would make that possible either." We simply have no empirical evidence to work with here except for what we can observe in our own solar system, and we have absolutely no way to know whether what we observe here could be considered "typical" or whether our system represents some extreme abberration... or even whether the interactions which govern stellar/planetary formation allow for the word "typical" to have any meaning whatsoever. So what you're saying is "Maybe, maybe not"? Wait, 1 to 6 moons?
Micro-g environmentThe term micro-g environment (also µg, often referred to by the term microgravity) is more or less a synonym of weightlessness and zero-G, but indicates that g-forces are not quite zero, just very small. The symbol for microgravity, µg, was used on the insignias of Space Shuttle flights STS-87 and STS-107, because these flights were devoted to microgravity research in Low Earth orbit. Absence of gravity A "stationary" micro-g environment would require travelling far enough into deep space so as to reduce the effect of gravity by attenuation to almost zero. This is the simplest in conception, but requires traveling an enormous distance, rendering it most impractical. For example, to reduce the gravity of the Earth by a factor of one million, one needs to be at a distance of 6 million km from the Earth, but to reduce the gravity of the Sun to this amount one has to be at a distance of 3700 million km. Compare the gravitational potential at some of these locations. 
Extrasolar planet2 January 2013: Astronomers state that the Milky Way may contain as many as 400 billion exoplanets, with almost every star hosting at least one planet. An exoplanet or extrasolar planet is a planet outside the Solar System. Around 1800 such planets have been discovered (1783 planets in 1105 planetary systems including 460 multiple planetary systems as of 18 April 2014). The nearest known exoplanet, if confirmed, would be Alpha Centauri Bb, but there is some doubt about its existence. For centuries philosophers and scientists supposed that extrasolar planets existed, but there was no way of detecting them or of knowing their frequency or how similar they might be to the planets of the Solar System. The discovery of extrasolar planets has intensified interest in the search for extraterrestrial life, particularly for those that orbit in the host star's habitable zone where it is possible for liquid water (and therefore life) to exist on the surface. Direct imaging
Unprecedented: Amateur astronomers discover a planet with four sunsFalse. At least in understanding, suns can be anywhere, Sol is the name of the star we orbit. Take your innacurate indignation elsewhere I thought we were in the Sol system? From what I've observed, a 'sun' is a title we give a star in relation to objects in its system, such as how we call large satellites 'moons'. I think it's more about point of view. Had the title read "solar system with four suns", I might not disagree with you, but we're talking about a planet; that planet orbits four stars, therefore that planet has four suns.ArchaeoastronomyArchaeoastronomy (also spelled archeoastronomy) is the study of how people in the past "have understood the phenomena in the sky, how they used these phenomena and what role the sky played in their cultures." Clive Ruggles argues it is misleading to consider archaeoastronomy to be the study of ancient astronomy, as modern astronomy is a scientific discipline, while archaeoastronomy considers symbolically rich cultural interpretations of phenomena in the sky by other cultures. It is often twinned with ethnoastronomy, the anthropological study of skywatching in contemporary societies. Archaeoastronomy is also closely associated with historical astronomy, the use of historical records of heavenly events to answer astronomical problems and the history of astronomy, which uses written records to evaluate past astronomical practice. Archaeoastronomy can be applied to all cultures and all time periods. History of archaeoastronomy ... Methodology Green archaeoastronomy
Darkest exoplanet spotted by astronomers12 August 2011Last updated at 11:09 By Jason Palmer Science and technology reporter, BBC News TrES-2b is literally darker, on average, than coal A dark alien world, blacker than coal, has been spotted by astronomers. The Jupiter-sized planet is orbiting its star at a distance of just five million km, and is likely to be at a temperature of some 1200C. The planet may be too hot to support reflective clouds like those we see in our own Solar System, but even that would not explain why it is so dark. The research will be published in the journal Monthly Notices of the Royal Astronomical Society. The planet, called TrES-2b, is so named because it was first spotted by the Trans-Atlantic Exoplanet Survey in 2006. It also lies in the field of view of the Kepler space telescope, whose primary mission is to spot exoplanets using extremely sensitive brightness measurements as far-flung worlds pass in front of their host stars. 'Exotic chemistry' Continue reading the main story