Planetary science, also known as planetology and closely related to planetary astronomy, is the science of planets, or planetary systems, and the solar system. Science (from the Latin scientia, meaning " Knowledge " or "knowing" is the effort to discover, and increase human understanding A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is The Solar System consists of the Sun and those celestial objects bound to it by Gravity. Incorporating an interdisciplinary approach, planetary science draws from diverse sciences and may be considered a part of the Earth sciences, or more logically, as its parent field. In Academia, Pedagogy, Physical sciences, Earth sciences, Human sciences and Social sciences Earth science (also known as geoscience, the geosciences or the Earth Sciences) is an all-embracing term for the Sciences related to the planet Research tends to be done by a combination of astronomy, space exploration (particularly robotic spacecraft missions), and comparative, experimental and meteorite work based on Earth. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study History First orbital flights The first successful orbital launch was of the Soviet unmanned Sputnik A robotic spacecraft is a Spacecraft with no humans on board that is usually under Telerobotic control A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface There is also an important theoretical component and considerable use of computer simulation. The word theory has many distinct meanings in different fields of Knowledge, depending on their methodologies and the context of discussion. A computer simulation, a computer model or a computational model is a Computer program, or network of computers that attempts to simulate an Astrogeology is a major component of planetary sciences. Planetary geology, alternatively known as astrogeology or exogeology, is a Planetary science discipline concerned with the Geology of the

Photograph of Apollo 15 orbital unit about the rilles in the vicinity of the crater Aristarchos. The arrangement of the two valleys is very similar, although one third in size, to Great Hungarian Plane rivers Danube and Tisza.

Planetology is an interdisciplinary science growing out from astronomy and earth science. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study Earth science (also known as geoscience, the geosciences or the Earth Sciences) is an all-embracing term for the Sciences related to the planet Its development was determined by the increasing importance of robotics and measuring technology. In general, planetary science studies the planets, their moons, all the bodies and radiations of the Solar System, the various force fields and interactions between the several components of the Solar system. The Solar System consists of the Sun and those celestial objects bound to it by Gravity.

Its relation to earth sciences

The earth science has a new discipline: geonomy, strongly related to planetary science. Earth science (also known as geoscience, the geosciences or the Earth Sciences) is an all-embracing term for the Sciences related to the planet Geonómia is a comprehensive earth science about earth science disciplines, extending a synthesis between them. Geonomy integrates the knowledge collected from the Earth. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 However, the sequence of collecting data from Earth and from the planets was different. Earth sciences began their studies in the vicinity of men, and it later grow up gradually to embrace the planet Earth.

Planetary science began in astronomy from studies of the light point planets and later it has got better and better resolution about the atmospheric or surface details. One exception was the Moon, which always exhibited details on its surface, because its small distance orbiting. The Moon has been known from the whole picture, from the size of a spherical body. The gradually better and better resolution resulted in more and more detailed geological knowledge about our natural satellite. In this scientific process astronomical telescope, (later radio telescope) and finally space probe robots played important role. A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation. A radio telescope is a form of directional Radio antenna used in Radio astronomy and in tracking and collecting data from Satellites A space probe is a scientific Space exploration mission in which a Robotic spacecraft leaves the Gravity well of Earth and approaches the

Planetary science involved all disciplines sometimes directed only terrestrial studies of mineralogy, petrology, geocehemistry. So we can speak today about cosmochemistry, cosmopetrography, or cosmo-geochemistry, too. Meteoritics studies the rocky and mineral materials of the Solar System. (There are important journals about it: The Geochimica et Cosmochimica Acta, and the Meteoritics and Planetary Science. )

The most important regular annual conference of this discipline is the Lunar and Planetary Science Conference (LPSC), organized by the Lunar and Planetary Institute in Houston, at NASA Lyndon B. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program Johnson Space Center (JSC). Since 1970 this (2008) year will see the 39. LPSC.

Investigations of the surface of the Moon, Mars and Venus

The most well known research topics of planetary science are the planetary bodies in the nearest vicinity of the Earth: the Moon, and the two neighbour planets: Venus and Mars. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Among them the Moon was the first, where those methods were used earlier developed on the Earth. Two important disciplines are in surface studies: geomorphology and stratigraphy. Geomorphology (from Greek: γη ge, "earth" μορφή morfé, "form" and λόγος Logos, "knowledge" Stratigraphy, a branch of Geology, studies rock layers and layering ( stratification)

Geomorphology

Geomorphology studies the features on the planetary surface and reconstructs their formational processes. It contains studies on: - features originating from the outer space effects, like impacts (multi-ringed basins, craters) - features originating from inner processes like volcanism and tectonism (lavaflows, fissures, rilles) - erosional objects produced by the continuous meteorite bombardment

On the Moon impact structures can be found in the wide size range from the basins with 1000 km diameter till the micrometer sized craterlets on the mineral grains. Volcanism produced extended lava flows, with wrinkle ridges, lava channels, exhibiting the morphological evidences of their formational processes. Erosion on the Moon produced the thin regolithic dust cover on the surface.

The objects of our geomorphological studies can be used to decipher the history of the surface. They can be mapped according their settling sequence from top to bottom, as determined first on terrestrial strat by Nicolas Steno. Nicolas Steno ( Danish: Niels Stensen; Latinized to Nicolaus Stenonis) ( January 10, 1638 - November 25, On the basis of this sequence stratigraphical mapping prepared the Apollo astronauts in their lunar mission works.

Stratigraphy

The stratigraphy studies and arranges the strata according to their settling sequence and summarizes them in stratigraphical maps. In order to identify strata and determine their sequence geology developed the geological (stratigraphical) axioms. They were applied to the Moon. The overlapping sequences were identified first on images and photometric, telescopic measurements, later remote sensing technologies were developed (Lunar Orbiter). Remote sensing is the small or large-scale acquisition of information of an object or phenomenon by the use of either recording or real-time sensing device(s that is not in physical The final product of this work was a Lunar stratigraphic column, showing the sequence of the main strata (and events, producing them), and the stratigraphical map of the Moon.

On the top of the lunar stratigraphical sequence rayed impact craters can be found. Such youngest craters belong to the Copernican unit. Below it can be found craters without the ray system, but with rather well developed impact crater morphology. This is the Eratosthenian unit. The two younger stratigraphical units can be found in crater sized spots on the Moon. Below them two extending strat can be found: mare units (earlier defined as Procellarian unit) and the Imbrium basin related ejecta and tectonic units (Imbrian units). Another impact basin raletad unit is the Nectarian unit, defined around the Nectarian Basin. At the bottom of the lunar stratigraphical sequence the pre-Nectarian unit of old crater plains can be found. The surface of Mercury is similar in many aspects to the Lunar one. The stratigraphy of Mercury is very similar to the lunar case, too.

Rocky materials from the planetary bodies with rigid surface

A branch of planetary science is the materials science studying rocks and minerals from the Solar System. There are three main source types of these materials: meteorites, lunar samples, and Martian samples.

Meteorites

First the meteorites were the known extraterrestrial materials. A meteorite is a natural object originating in Outer space that survives an impact with the Earth 's surface Since 200 years they are continuously collected and studied collecting data about their parent bodies. Meteorites mostly originated from smaller asteroidal bodies of the solar system. Therefore they are beneficial to study the evolution of these asteroidal bodies. Chondrites in particular (containing chondtuels, small "grains"- greek word) are very important to see primordial materials from the early solar system age.

Lunar rocks

During the Apollo era, in the Apollo program, lunar samples were collected and transported to the Earth (384 kilogramm) and 3 Luna-robots also delivered regolith samples from the Moon. Moon Rock is the debut Album by Paul Steel. It was cancelled for release after the album's first single Your Loss failed to chart upon Regolith ( Greek: "blanket rock" is a layer of loose Heterogeneous material covering solid rock. Finally lunar meteorites were also found among the Antarctic meteorites. Today about 100 paired lunar meteorites are known (in 2008).

Martian meteorites

Third group of planetary materials are the Martian meteorites. Today about 50 paired Martian meteorites are known (in 2008).

Studies of the force fields of the planets

Space probes made it possible, that data should be collected not only the visible light region, but in other parts of the electromagnetic spectrum. It became possible to study the outer empty and rarely populated material space around planets too.

The planets are characterized by their force fields, too: by the gravity and by the magnetic field. The magnetic field and the interaction with the solar wind forms the magnetosphere around a planet with strong magnetic field. In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges A magnetosphere' is a highly magnetized region around and possessed by an Astronomical object. Some examples will be shown.

Magnetic force field

Early space probes discovered the main aspects of the terrestrial magnetic field. It extends about 10 terrestrial radius distance towards the Sun. The corpuscular radiations of the Sun streams around the terrestrial magnetic field forming a magnetic chamber (magnetosphere), and close again after forming the magnetic tail, hundreds of terrestrial radius distance.

Inside the magnetosphere radiation belts are forming where the density of the charged particles is high (Van Allen radiation belt). The Van Allen radiation belt is a Torus of energetic Charged particles ( plasma) around Earth, held in place by Earth's Magnetic

Gravity fields

Spatial acceleration of the space probes was used to measure the fine details of the gravity field of the planets. First the gravity field disturbances above lunar maria were measured and the mascons were discovered. Lunar Orbiters found 5 lunar mascons which are at Imbrium, Serenitatis, Crisium, Nectaris and Humorum basins. They are known since the 1970s.

Effects of the rotational force field on the atmospheres

The atmosphere is an important transitional material zone between the solid planetary surface and the higher rare ionizing and radiation belts. Not all of the planets have atmospheres, because its existence depends on the mass of the planet. Besides the four giant planets, Earth, Venus, and Mars have atmospheres, and Saturn's moon Titan also has one. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University TemplateInfobox Planet.--> Titan (ˈtaɪtən, or as

The rotation of the planet affects its body shape, too. More expressed effects of rotation can be seen on the atmospheric streams. The cloudy system in the atmosphere exhibits well these affects by its striped features. Even amateur telescopes show the stripe system of Jupiter and Saturn. Such belts has the name in the terrestrial circulation: Hadley-cells.

Comparative planetary science

The bodies of the Solar System gradually formed and reached their recent state we observe today. These bodies started in their evolution in different initial conditions, considering their composition and mass, solar distance and other parameters. Therefore it is important to follow and describe the evolutionary path of these individual objects and the comparison of them. The comparative planetology is a discipline of various celestial planetary "laboratories", the planets and other bodies themselves. Many decades of future space probe investigations are necessary to make detailed evolutionary history of planetary bodies and comparative work may help to interpolate some of the hiatus in the known evolutionary histories. For example lunar history has helped us to see the first 3 aeons of the Solar System events which were mostly destroyed on Earth.

Planetary science studies objects ranging in size from micrometeoroids to gas giants, their composition, dynamics and history. A Micrometeoroid (also micrometeorite, micrometeor) is a tiny Meteoroid; a small particle of rock in space usually weighing less than a Gram A gas giant (sometimes also known as a Jovian planet after the planet Jupiter, or giant planet) is a large Planet that is not primarily

Terminology

When the discipline concerns itself with a celestial body in particular, a specialized term is used, as shown in the table below (only heliology, geology, selenology, and areology are currently in common use):

Body	Planetary science	Source of root
Sun	heliology	Greek Helios
Mercury	hermeology	Greek Hermes
Venus	cytherology	Greek Aphrodite
Earth	geology	Greek Gaia
( Moon	selenology	Greek Selene )
Mars	areology	Greek Ares
Ceres	demeterology	Greek Demeter
Jupiter	zenology	Greek Zeus
Saturn	kronology	Greek Cronus
Uranus	uranology	Greek/Latin Uranus
Neptune	poseidology	Greek Poseidon
Pluto	hadeology	Greek Hades
Eris	eridology	Greek Eris

Basic Concepts

• Asteroid
• Brown dwarfs
• Celestial mechanics
• Comets
• Earthquake
• Equatorial bulge
• Extrasolar planets
• Gas giant
• Geophysics
• Icy moons
• Kuiper belt
• Magnetosphere
• Planet
• Planetary differentiation
• Planetary system
• The Pluto debate
• Precession
• Space weather
• Space weathering
• Star system
• Sun
• Synchronous rotation
• Terrestrial planets

References

• Basilevsky, A. The Sun (Sol is the Star at the center of the Solar System. In Greek mythology the Sun was personified as Helios (ˈhiliˌɑs ( Ἥλιος Latinized as Helius) The surface of Mercury is dominated by Impact craters, and lava plains similar in some respects to the Lunar maria. Hermes ( Greek,, ˈhɝmiːz in Greek mythology, is the Olympian god of boundaries and of the travelers who cross them of Shepherds and The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Venus has striking surface characteristics which are as beautiful as they are unusual EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Gaia (ˈgeɪə or /ˈgaɪə/ (" land " or " Earth " from the Ancient Greek Γαîα also Gæa or Gea The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to "lunar In Greek mythology, Selene (Σελήνη " Moon " English sɛˈliːniː was an archaic Lunar deity and the daughter of the Titans The geology of Mars, also known as areology (from Greek grc Ἂρης Arēs, " Ares " and grc -λογία -logia In Greek mythology, Ares ( Ancient Greek:, Μodern Greek Άρης) is the son of Zeus and Hera. Ceres (ˈsɪəriːz Demeter (dɨˈmiːtɚ Greek:, possibly "distribution-mother" from the noun of the Indo-European mother-earth * dheghom * mater Zeus (zjuːs in Greek: nominative: Zeús /zdeús/ genitive: Diós; Modern Greek /'zefs/ in Greek mythology Cronus or Kronos, ( Ancient Greek Κρόνος Krónos) was the leader and the youngest of the first generation of Titans, divine descendants Uranus (ˈjʊərənəs jʊˈreɪnəs is the Latinized form of Ouranos () the Greek word for Sky. Neptune ( English|AmE] ] is the eighth and farthest Planet from the Sun in the Solar System. In Greek mythology, Poseidon ( Greek:; Latin: Neptūnus) was the god of the Sea and as "Earth-Shaker" Hades (from Greek, Hadēs, originally, Haidēs or, Aidēs, probably from Indo-European *n̥-wid- 'unseen' refers both to the ancient Eris ( Greek Ἔρις, "Strife" is the Greek Goddess of strife her name being translated into Latin as Discordia Asteroids, sometimes called Minor planets or planetoids', are bodies—primarily of the inner Solar System —that are smaller than planets but Brown dwarfs are sub- stellar objects with a mass below that necessary to maintain Hydrogen -burning Nuclear fusion reactions in their cores as do stars Celestial mechanics is the branch of Astrophysics that deals with the motions of Celestial objects The field applies principles of Physics, historically A comet is a small Solar System body that orbits the Sun and when close enough to the Sun exhibits a visible coma (atmosphere or a tail — An earthquake is the result of a sudden release of energy in the Earth 's crust that creates Seismic waves Earthquakes are recorded with a Seismometer An equatorial bulge is a bulge which a planet may have around its Equator, distorting it into an Oblate spheroid. An extrasolar planet, or exoplanet, is a Planet beyond the Solar System, orbiting around other Stars As of September 2008 312 A gas giant (sometimes also known as a Jovian planet after the planet Jupiter, or giant planet) is a large Planet that is not primarily Geophysics, a major discipline of Earth sciences, is the study of the Earth by quantitative physical methods especially by seismic, electromagnetic Icy moons are believed to be a common class of Natural satellites or Planetoids with surfaces comprise mostly of Ice. The Kuiper belt (ˈkaɪpɚ to rhyme with "viper" sometimes called the Edgeworth-Kuiper belt, is a region of the Solar System beyond the planets extending A magnetosphere' is a highly magnetized region around and possessed by an Astronomical object. A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is In Planetary science, planetary differentiation is the process of separating out different constituents of a planetary body as a consequence of their physical or chemical Precession refers to a change in the direction of the axis of a rotating object Space weather is the concept of changing environmental conditions in Outer space. Space weathering is a blanket term used for a number of processes that act on any body exposed to the harsh space environment A star system or stellar system is a small number of Stars which orbit each other bound by gravitational attraction. The Sun (Sol is the Star at the center of the Solar System. In Astronomy, synchronous rotation is a planetological term describing a body orbiting another where the orbiting body takes as long to rotate A terrestrial planet, telluric planet or rocky planet is a Planet that is primarily composed of Silicate rocks Within our T. ,& J. W. Head (1995): Regional and global stratigraphy of Venus: a preliminary assessment and implications for the geological history of Venus Planetary and Space Science 43/12, pp. 1523-1553
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• Gradstein, F. M. , James G. Ogg, Alan G. Smith, Wouter Bleeker & Lucas J. Lourens (2004): A new Geologic Time Scale, with special reference to Precambrian and Neogene Episodes, Vol. 27, no. 2.
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See also

• Astrogeology
• Planetary habitability
• Europlanet

External links

• E. Planetary geology, alternatively known as astrogeology or exogeology, is a Planetary science discipline concerned with the Geology of the Planetary habitability is the measure of a Planet 's or a Natural satellite 's potential to develop and sustain Life. Europlanet is a network linking planetary scientists from across Europe. Grayzeck, D. R. Williams (2006-05-11). Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 330 - Byzantium is renamed ''Nova Roma'' during a dedication ceremony but is more popularly referred to as Constantinople Lunar and Planetary Science (English). NASA. Retrieved on 2006-08-21. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 1192 - Minamoto Yoritomo becomes Seii Tai Shōgun and the De facto ruler of Japan.
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