Three-box styling

Three-box design is a broad automotive styling term describing a sedan, coupé, notchback or hatchback where — when viewed in profile — principle volumes are articulated into three separate compartments or boxes: engine, passenger and cargo.[1]
Three-box designs are highly variable. The Renault Dauphine is a three-box that carries its engine in the rear and its cargo up front. The styling of the 2008 Škoda Superb integrates a hatchback (marketed as the TwinDoor, operable as a trunk lid or as a full hatchback) with the articulation of a three-box. As with the third generation European Ford Escort (also a hatchback), the third box may be vestigial. And three-box styling need not be boxy: Car Design News calls the fluid and rounded Fiat Linea a three-box design[2] — and most examples of the markedly bulbous styling of the ponton genre are three-box designs.

Car body style

Automobiles body styles are highly variable. Some body styles remain in production, while others become less common or obsolete. They may or may not correlate to a car's price, size or intended market classification. The same car model might be available in multiple body styles comprising a model range. Some distinctions, as with four-wheel drive vs. SUV models or minivan vs. MPV models, the distinction between body style and classification can be particularly narrow.
While body styles have historical and technical definitions, in common usage such definitions are broad and may be ambiguous. For example, one person may call a 4-passenger sport coupé a "sports car", while another may define a sports car strictly as a two-place vehicle.

Styles in current use4WD ("four-by-four" or "four-wheel drive")
A four-wheeled vehicle with a drivetrain that allows all four wheels to receive power from the engine simultaneously. The terms are usually (but not exclusively) used in Europe to describe what is referred to in North America as a sport utility vehicle or SUV (see below).
Buggy
A Buggy is an automobile with wheels that project beyond the vehicle chassis.
Cabrio coach or Semi-convertible
A form of car roof, where a retractable textile cover amounts to a large sunroof. Fundamental to various older designs such as the Citroën 2CV; sometimes an option on modern cars.
Cabriolet
A term for a convertible (see below).

A BMW M3 convertible
Convertible
A body style with a flexible textile folding roof or rigid retracting roof — of highly variable design detail — to allow driving in open or enclosed modes.
Coupé
A 2-door, 2- or 4-seat car with a fixed roof. Its doors are often longer than those of an equivalent sedan and the rear passenger area smaller; the roof may also be low. In cases where the rear seats are very small and not intended for regular use it is called a 2+2 (pronounced "two plus two"). Originally, a coupé was required to have only one side window per side, but this consideration has not been used for many years.
Coupé utility (ute)
the coupé utility is a passenger-car derived vehicle with coupé passenger cabin lines and an integral cargo bed.
Crossover (or CUV)
A loose marketing term to describe a vehicle that blends features of a SUV with features of a car — especially forgoing the body on frame construction of the SUV in favor of the car's unibody or monocoque construction.
Estate car
British name for a station wagon.
Fastback
A design where the roof slopes at a smooth angle to the tail of the car, but the rear window does not open as a separate "door".
Hardtop
A style of car roof. Originally referred to a removable solid roof on a convertible; later, also a fixed-roof car whose doors have no fixed window frames, which is designed to resemble such a convertible.

Tata Nano Europa, a compact hatchback
Hatchback
Identified by a rear door including the back window that opens vertically to access a storage area not separated from the rest of the passenger compartment. May be 3 or 5-door and 2 to 5 seats, but generally in the US the tailgate isn't counted making it a 2-door and 4-door.
Hearse
A converted car (often a station wagon), light truck or minivan usually used to transport the dead. Often longer and heavier than the vehicle on which they are usually based. Can sometimes double up as an ambulance in some countries, such as the United States, especially in rural areas.
Leisure activity vehicle
A small van, generally related to a supermini, with a second or even a third seat row, and a large, tall boot.
Liftback
A style of coupé with a hatchback; used especially when the rear access door is very inclined, opening more upward that outward.

A Lincoln Town Car limousine
Limousine
By definition, a chauffeur-driven car with a (normally glass-windowed) division between the front seats and the rear. In German, the term simply means a sedan.
Minibus
Designed to carry fewer people than a full-size bus, generally up to 16 people in multiple rows of seats. Passenger access in normally via a sliding door on one side of the vehicle. One example of a van with a minibus version available is the Ford Transit.
Microvan
Term for a boxy wagon-type of car that is smaller than a conventional minivan; often without rear sliding door(s). Examples are Citroën Picasso, Renault Scénic, Toyota Yaris Verso or Mercedes-Benz A-Class.
Minivan
North American term for a boxy wagon-type of car usually containing three or four rows of seats, with a capacity of six or more passengers. Often with extra luggage space also. As opposed to the larger van, the minivan was developed primarily as a passenger vehicle, though is more van-like than a station wagon. In Britain, these are generally referred to as people carriers.
MPV
Multi-purpose vehicle, a large car or small bus designed to be used on and off-road and easily convertible to facilitate loading of goods from facilitating carrying people.
Notchback
A configuration where the third box of a three-box styling configuration is less pronounced — especially where the rear deck (third box) is short or where the rear window is upright.
People carrier or people mover
European name to describe what is usually referred to in North America as an Minivan.
Pickup truck a.k.a pickup
A small, medium, or large-sized truck, though smaller in every case than a Semi tractor truck. The passenger cabin is wholly separated from the cargo bed.
Pillarless
Usually a prefix to coupé, fastback, or hardtop; completely open at the sides when the windows are down, without a central pillar, e.g. the Sunbeam Rapier fastback coupé.
Ragtop
Originally an open car like a roadster, but with a soft top (cloth top) that can be raised or lowered. Unlike a convertible, it had no roll-up side windows. Now often used as slang for a convertible.
Retractable Hardtop
aka Coupé convertible or Coupé Cabriolet. A type of convertible forgoing a foldable textile roof in favor of a multi-segment rigid roof retracts into the lower bodywork.
Roadster
Originally a two-seat open car with minimal weather protection — without top or side glass — though possibly with optional hard or soft top and side curtains (i.e., without roll-up glass windows). In modern usage, the term means simply a two-seat sports car convertible, a variation of spyder.
Sedan
A car seating four or more with a fixed roof that is full-height up to the rear window. Known in British English as a saloon. Sedans can have 2 or 4-doors. This is the most common body style[citation needed]. In the U.S., this term has been used[who?] to denote a car with fixed window frames, as opposed to the hardtop style wherein the sash, if any, winds down with the glass.

Chevrolet HHR sedan delivery
Sedan delivery
North American term for a vehicle similar to a wagon but without side windows, similar to a panel truck but with two doors (one on each side), and one or two rear doors . Often shortened to delivery; used alone, "delivery" is presumed to be a sedan delivery. No longer manufactured.
Sport utility vehicle (SUV)
Derivative of a pickup truck or 4-wheel-drive vehicle, but with fully-enclosed passenger cabin interior and carlike levels of interior equipment.
Spyder (or Spider)
Similar to a roadster but originally with less weather protection. The term originated from a small two-seat horse cart with a folding sunshade made of four bows.[citation needed] With its black cloth top and exposed sides for air circulation, the top resembled a spider. Nowadays it simply means a convertible sports car.
Shooting brake
A two-door estate car; generally for vintage or extremely expensive vehicles. They were vehicles for the well-off shooter and hunter, giving space to carry shotguns and other equipment. Usually made to order by coachbuilders.[citation needed] The term is occasionally revived.
Station wagon
A car with a full-height body all the way to the rear; the load-carrying space created is accessed via a rear door or doors. Sometimes shortened to just wagon.
Surrey top
Similar to the Porsche Targa top, the surrey top was developed by Triumph in 1962 for the TR4.
T-top
A derivative of the Targa top, called a T-bar roof, this fixed-roof design has two removable panels and retains a central narrow roof section along the front to back axis of the car (e.g. Toyota MR2 Mark I.)
Targa top
A semi-convertible style used on some sports cars, featuring a fully removable hard top roof panel which leaves the A and B pillars in place on the car body. (e.g. Fiat X1/9). Strictly, the term originated from and is trademarked by Porsche for a derivate of its 911 series, the Porsche 911 Targa, itself named after the famous Targa Florio rally. A related styling motif is the Targa band, sometimes called a wrapover band which is a single piece of chrome or other trim extending over the roof of the vehicle and down the sides to the bottom of the windows. It was probably named because the original Porsche Targa had such a band behind its removable roof panel in the late 60s.
Ute
Australian/New Zealand English term for the Coupe Utility body style (see above). Sometimes used informally to refer to any utility vehicle, particularly light trucks such as a pickup truck. In American English, sport-ute is sometimes used[who?] to refer to an SUV (see above).

A Dodge Sprinter, one particular model of van.
Van
In North America "van" refers to a truck-based commercial vehicle of the wagon style, whether used for passenger or commercial use. Usually a van has no windows at the side rear (panel van), although for passenger use, side windows are included. In other parts of the world, 'van' denotes a passenger-based wagon with no rear side windows.
Wagon delivery
North American term (mainly U.S. and Canada). Similar to a sedan delivery, with four doors. Sometimes shortened to delivery; used alone, "delivery" is presumed to be a sedan delivery. No longer manufactured.
[edit] Non-English terms
Some non-English language terms are familiar from their use on imported vehicles in English-speaking nations even though the terms have not been adopted into English.
Barchetta
Italian term for a roadster. The name means, roughly, "small boat".
Berlina
Italian term for a sedan.
Berline
French term for a sedan.
Berlinetta
Italian term for a sport coupé.
Break
French term for a station wagon.
Carrinha
Portuguese term for a station wagon. Not used in Brazilian Portuguese.
Espada
Portuguese nickname for a limousine (the same word for Sword - long piece of metal). Not used in Brazilian Portuguese.
Furgoneta
Portuguese term for a van. Not used in Brazilian Portuguese.
Furgão
Portuguese alternative term (less used) for a van. Used in Brazilian Portuguese.
Giardinetta
Italian term for a station wagon.
Jeep
Russian, Bulgarian, German, Portuguese, Hebrew and Greek term for a sport utility vehicle. Originally from the English-language jeep, of which the name's origins can be researched on the Jeep page.
Kombi
is a German abbreviation of "Kombinationswagen" (Combination Car) and it is German name for station wagon. Since Germany is a major producer of cars for many European countries, the term Kombi in this meaning is also used in Swedish, Czech, Slovak, Polish, Slovenian, Serbian, Croatian, Hungarian, Spanish, Portuguese, Bulgarian. In Afrikaans, Kombi is also used to refer to a Volkswagen Microbus
Minibus
Danish term for Minivan.
Stationcar
Danish term for station wagon.
Turismo
Spanish term for a sedan. Literally means tourism, used mostly in Latin American countries.

French kiss

A French kiss is a kiss, usually romantic or sexual, in which one participant's tongue touches the other's tongue and usually enters his or her mouth.
In many parts of the world, 'tongue kissing' as a public display of affection is discouraged and may even be regarded as taboo. The 1994 Chinese film Impetuous Fire caused controversy amongst some Chinese viewers for a kiss between Chinese-American actor Tim Chang and actress Sandy Wu.

Etymology of 'French kiss'The colloquial term, "French kissing", does not necessarily stem from France. In France, it is referred to as 'baiser amoureux' (love kiss) or 'baiser avec la langue' (kiss with the tongue), even if in past times it was also known as baiser florentin (Florentine kiss). In French slang, a "French kiss" is called a "patin" (ice skating shoe) or a "galoche". Doing a French kiss is referred to "rouler un patin" (roll a skate, as in ice skating shoe) or "rouler une pelle" (roll a shovel). The term 'French Kiss' is cited in Private Lindner’s letters: Censored and uncensored letters, anecdotes, sketches, a collection of items gathered during World War I and published in 1939

Inner Solar System

The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids.[30] Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is shorter than the distance between Jupiter and Saturn.
Inner planets
Main article: Terrestrial planet

The inner planets. From left to right: Mercury, Venus, Earth, and Mars (sizes to scale, interplanetary distances not)
The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates which form their crusts and mantles, and metals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets which are closer to the Sun than Earth is (i.e. Mercury and Venus).

Mercury
Mercury (0.4 AU from the Sun) is the closest planet to the Sun and the smallest planet in the Solar System (0.055 Earth masses). Mercury has no natural satellites, and its only known geological features besides impact craters are lobed ridges or rupes, probably produced by a period of contraction early in its history.[31] Mercury's almost negligible atmosphere consists of atoms blasted off its surface by the solar wind.[32] Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, and that it was prevented from fully accreting by the young Sun's energy.

Venus
Venus (0.7 AU from the Sun) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere.[35] No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions

Earth
Earth (1 AU from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and is the only place in the universe where life is known to exist.[37] Its liquid hydrosphere is unique among the terrestrial planets, and it is also the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen.[38] It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System.

Mars

Mars (1.5 AU from the Sun) is smaller than Earth and Venus (0.107 Earth masses). It possesses an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (roughly 0.6 percent that of the Earth's).[39] Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago.[40] Its red colour comes from iron oxide (rust) in its soil.[41] Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids.[42]

Asteroid belt

Main article: Asteroid belt

Image of the main asteroid belt and the Trojan asteroids
Asteroids are mostly small Solar System bodies[e] composed mainly of refractory rocky and metallic minerals.[43]
The main asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.[44]
Asteroids range in size from hundreds of kilometres across to microscopic. All asteroids save the largest, Ceres, are classified as small Solar System bodies, but some asteroids such as Vesta and Hygieia may be reclassed as dwarf planets if they are shown to have achieved hydrostatic equilibrium.[45]
The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter.[46] Despite this, the total mass of the main belt is unlikely to be more than a thousandth of that of the Earth.[47] The main belt is very sparsely populated; spacecraft routinely pass through without incident. Asteroids with diameters between 10 and 10−4 m are called meteoroids.[48]

Ceres

Ceres (2.77 AU) is the largest body in the asteroid belt and is classified as a dwarf planet.[e] It has a diameter of slightly under 1000 km, and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in the 19th century, but was reclassified as an asteroid in the 1850s as further observation revealed additional asteroids.[49] It was again reclassified in 2006 as a dwarf planet.
Asteroid groups
Asteroids in the main belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets which may have been the source of Earth's water.[50]
Trojan asteroids are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term "Trojan" is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits.[51]
The inner Solar System is also dusted with rogue asteroids, many of which cross the orbits of the inner planets

Inner Solar System

The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids.[30] Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is shorter than the distance between Jupiter and Saturn.
Inner planets
Main article: Terrestrial planet

The inner planets. From left to right: Mercury, Venus, Earth, and Mars (sizes to scale, interplanetary distances not)
The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates which form their crusts and mantles, and metals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets which are closer to the Sun than Earth is (i.e. Mercury and Venus).

Mercury
Mercury (0.4 AU from the Sun) is the closest planet to the Sun and the smallest planet in the Solar System (0.055 Earth masses). Mercury has no natural satellites, and its only known geological features besides impact craters are lobed ridges or rupes, probably produced by a period of contraction early in its history.[31] Mercury's almost negligible atmosphere consists of atoms blasted off its surface by the solar wind.[32] Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, and that it was prevented from fully accreting by the young Sun's energy.

Venus
Venus (0.7 AU from the Sun) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere.[35] No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions

Earth
Earth (1 AU from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and is the only place in the universe where life is known to exist.[37] Its liquid hydrosphere is unique among the terrestrial planets, and it is also the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen.[38] It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System.

Mars

Mars (1.5 AU from the Sun) is smaller than Earth and Venus (0.107 Earth masses). It possesses an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (roughly 0.6 percent that of the Earth's).[39] Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago.[40] Its red colour comes from iron oxide (rust) in its soil.[41] Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids.[42]

Asteroid belt

Main article: Asteroid belt

Image of the main asteroid belt and the Trojan asteroids
Asteroids are mostly small Solar System bodies[e] composed mainly of refractory rocky and metallic minerals.[43]
The main asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.[44]
Asteroids range in size from hundreds of kilometres across to microscopic. All asteroids save the largest, Ceres, are classified as small Solar System bodies, but some asteroids such as Vesta and Hygieia may be reclassed as dwarf planets if they are shown to have achieved hydrostatic equilibrium.[45]
The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter.[46] Despite this, the total mass of the main belt is unlikely to be more than a thousandth of that of the Earth.[47] The main belt is very sparsely populated; spacecraft routinely pass through without incident. Asteroids with diameters between 10 and 10−4 m are called meteoroids.[48]

Ceres

Ceres (2.77 AU) is the largest body in the asteroid belt and is classified as a dwarf planet.[e] It has a diameter of slightly under 1000 km, and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in the 19th century, but was reclassified as an asteroid in the 1850s as further observation revealed additional asteroids.[49] It was again reclassified in 2006 as a dwarf planet.
Asteroid groups
Asteroids in the main belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets which may have been the source of Earth's water.[50]
Trojan asteroids are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term "Trojan" is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits.[51]
The inner Solar System is also dusted with rogue asteroids, many of which cross the orbits of the inner planets

Inner Solar System

The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids.[30] Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is shorter than the distance between Jupiter and Saturn.
Inner planets
Main article: Terrestrial planet

The inner planets. From left to right: Mercury, Venus, Earth, and Mars (sizes to scale, interplanetary distances not)
The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates which form their crusts and mantles, and metals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets which are closer to the Sun than Earth is (i.e. Mercury and Venus).

Mercury
Mercury (0.4 AU from the Sun) is the closest planet to the Sun and the smallest planet in the Solar System (0.055 Earth masses). Mercury has no natural satellites, and its only known geological features besides impact craters are lobed ridges or rupes, probably produced by a period of contraction early in its history.[31] Mercury's almost negligible atmosphere consists of atoms blasted off its surface by the solar wind.[32] Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, and that it was prevented from fully accreting by the young Sun's energy.

Venus
Venus (0.7 AU from the Sun) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere.[35] No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions

Earth
Earth (1 AU from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and is the only place in the universe where life is known to exist.[37] Its liquid hydrosphere is unique among the terrestrial planets, and it is also the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen.[38] It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System.

Mars

Mars (1.5 AU from the Sun) is smaller than Earth and Venus (0.107 Earth masses). It possesses an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (roughly 0.6 percent that of the Earth's).[39] Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago.[40] Its red colour comes from iron oxide (rust) in its soil.[41] Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids.[42]

Asteroid belt

Main article: Asteroid belt

Image of the main asteroid belt and the Trojan asteroids
Asteroids are mostly small Solar System bodies[e] composed mainly of refractory rocky and metallic minerals.[43]
The main asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.[44]
Asteroids range in size from hundreds of kilometres across to microscopic. All asteroids save the largest, Ceres, are classified as small Solar System bodies, but some asteroids such as Vesta and Hygieia may be reclassed as dwarf planets if they are shown to have achieved hydrostatic equilibrium.[45]
The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter.[46] Despite this, the total mass of the main belt is unlikely to be more than a thousandth of that of the Earth.[47] The main belt is very sparsely populated; spacecraft routinely pass through without incident. Asteroids with diameters between 10 and 10−4 m are called meteoroids.[48]

Ceres

Ceres (2.77 AU) is the largest body in the asteroid belt and is classified as a dwarf planet.[e] It has a diameter of slightly under 1000 km, and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in the 19th century, but was reclassified as an asteroid in the 1850s as further observation revealed additional asteroids.[49] It was again reclassified in 2006 as a dwarf planet.
Asteroid groups
Asteroids in the main belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets which may have been the source of Earth's water.[50]
Trojan asteroids are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term "Trojan" is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits.[51]
The inner Solar System is also dusted with rogue asteroids, many of which cross the orbits of the inner planets

Inner Solar System

The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids.[30] Composed mainly of silicates and metals, the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is shorter than the distance between Jupiter and Saturn.
Inner planets
Main article: Terrestrial planet

The inner planets. From left to right: Mercury, Venus, Earth, and Mars (sizes to scale, interplanetary distances not)
The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals, such as the silicates which form their crusts and mantles, and metals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets which are closer to the Sun than Earth is (i.e. Mercury and Venus).

Mercury
Mercury (0.4 AU from the Sun) is the closest planet to the Sun and the smallest planet in the Solar System (0.055 Earth masses). Mercury has no natural satellites, and its only known geological features besides impact craters are lobed ridges or rupes, probably produced by a period of contraction early in its history.[31] Mercury's almost negligible atmosphere consists of atoms blasted off its surface by the solar wind.[32] Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, and that it was prevented from fully accreting by the young Sun's energy.

Venus
Venus (0.7 AU from the Sun) is close in size to Earth, (0.815 Earth masses) and like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere.[35] No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions

Earth
Earth (1 AU from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and is the only place in the universe where life is known to exist.[37] Its liquid hydrosphere is unique among the terrestrial planets, and it is also the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen.[38] It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System.

Mars

Mars (1.5 AU from the Sun) is smaller than Earth and Venus (0.107 Earth masses). It possesses an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (roughly 0.6 percent that of the Earth's).[39] Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago.[40] Its red colour comes from iron oxide (rust) in its soil.[41] Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids.[42]

Asteroid belt

Main article: Asteroid belt

Image of the main asteroid belt and the Trojan asteroids
Asteroids are mostly small Solar System bodies[e] composed mainly of refractory rocky and metallic minerals.[43]
The main asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.[44]
Asteroids range in size from hundreds of kilometres across to microscopic. All asteroids save the largest, Ceres, are classified as small Solar System bodies, but some asteroids such as Vesta and Hygieia may be reclassed as dwarf planets if they are shown to have achieved hydrostatic equilibrium.[45]
The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter.[46] Despite this, the total mass of the main belt is unlikely to be more than a thousandth of that of the Earth.[47] The main belt is very sparsely populated; spacecraft routinely pass through without incident. Asteroids with diameters between 10 and 10−4 m are called meteoroids.[48]

Ceres

Ceres (2.77 AU) is the largest body in the asteroid belt and is classified as a dwarf planet.[e] It has a diameter of slightly under 1000 km, and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in the 19th century, but was reclassified as an asteroid in the 1850s as further observation revealed additional asteroids.[49] It was again reclassified in 2006 as a dwarf planet.
Asteroid groups
Asteroids in the main belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets which may have been the source of Earth's water.[50]
Trojan asteroids are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term "Trojan" is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits.[51]
The inner Solar System is also dusted with rogue asteroids, many of which cross the orbits of the inner planets