Minor planetA minor planet, according to the International Astronomical Union (IAU), is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet.
Dwarf planetA dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be gravitationally rounded, but insufficient to achieve orbital dominance like the eight classical planets of the Solar System. The prototypical dwarf planet is Pluto, which for decades was regarded as a planet before the "dwarf" concept was adopted in 2006.
Space probeA space probe is an uncrewed robotic spacecraft designed to explore outer space and transmit scientific data back to Earth. Space probes are used to investigate the Moon, planets, moons, asteroids, comets, the Sun, and interstellar space. Unlike artificial satellites, which usually remain in orbit around Earth, probes are sent beyond Earth orbit toward other celestial bodies or into deep space.
AsteroidAn asteroid is a minor planet—an object larger than a meteoroid (thus 1 meter or larger) that is neither a planet nor an identified comet—that orbits within the inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type (carbonaceous), M-type (metallic), or S-type (silicaceous).
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.
Kuiper beltArea of the Solar System beyond the planets, comprising small bodiesKnown objects in the Kuiper belt beyond the orbit of Neptune. (Scale in AU. Distances but not sizes are to scale; the yellow disk is about the size of Mars's orbit. Epoch as of January 2015.)
Natural satelliteAstronomical body that orbits a planetThe Moon orbiting around Earth (observed by the Deep Space Climate Observatory)A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, by analogy with the Moon, Earth's natural satellite.
CometNatural object in space that releases gasA comet is an icy, small Solar System body or interstellar object that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma.
MarsFourth planet from the SunSurface absorbed doserate8.8 μGy/hSurface equivalent doserate27 μSv/hApparent magnitude−2.94 to +1.86Absolute magnitude (H)−1.5Angular diameter3.5–25.1 arcsecondsAtmosphereSurface pressure0.636 (0.4–0.87) kPa0.00628 atmComposition by volume95.97% carbon dioxide1.93% argon1.89% nitrogen0.146% oxygen0.0557% carbon monoxide0.0210% water vaporMars is the fourth planet from the Sun.
SpacecraftA spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (carrier rocket).
C/2013 A1 (Siding Spring)C/2013 A1 (Siding Spring) is an Oort cloud comet discovered on 3 January 2013 by Robert H. McNaught at Siding Spring Observatory using the 0.5-meter (20 in) Uppsala Southern Schmidt Telescope. At the time of discovery it was 7.2 AU (1.08 billion km) from the Sun and located in the constellation Lepus. Comet C/2013 A1 probably took millions of years to come from the Oort cloud.*As an Amazon Associate I earn from qualifying purchases.