SpeedIn kinematics, the speed of a moving object is the rate at which the distance travelled by the object changes with time. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is the magnitude of velocity (a vector), which indicates additionally the direction of motion.
Barycenter (astronomy)In astronomy, the barycenter (or barycentre; from Ancient Greek (barús)'heavy' and (kéntron)'center') is the center of mass around which two or more bodies orbit. A barycenter is a dynamical point, not a physical object. It is an important concept in fields such as astronomy and astrophysics. The distance from a body's center of mass to the barycenter can be calculated as a two-body problem.
OrbitIn celestial mechanics, an orbit is the curved trajectory of an object under the influence of an attracting force. Alternatively, it is known as an orbital revolution, because it is a rotation around an axis external to the moving body. Examples for orbits include the trajectory of a planet around a star, a natural satellite around a planet, or an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point.
Astronomical objectAn astronomical object, celestial object, stellar object or heavenly object is a naturally occurring physical entity, association, or structure that exists within the universe. In astronomy, the terms object and body are often used interchangeably.
Primary bodyPrime astronomical designated entity within a gravitational system Motion of the Solar System's barycenter relative to the Sun A primary body – also called a central body, host body, gravitational primary, or simply primary – is the main physical body of a gravitationally bound, multi-object system. This object constitutes most of that system's mass and will generally be located near the system's barycenter.
Gravitational binding energyThe gravitational binding energy of a system is the minimum energy which must be added to it in order for the system to cease being in a gravitationallybound state. A gravitationally bound system has a lower (i.e., more negative) gravitational potential energy than the sum of the energies of its parts when these are completely separated—this is what keeps the system in accordance with the minimum total potential energy principle.
Center of massIn physics, the center of mass of a distribution of mass in space (sometimes referred to as the barycenter or balance point) is the unique point at any given time where the weighted relative position of the distributed mass sums to zero. For a rigid body containing its center of mass, this is the point to which a force may be applied to cause a linear acceleration without an angular acceleration.
StarLarge self-illuminated object in spaceThe Sun, a G-type main-sequence star, the closest to EarthA star-forming region in the Large Magellanic CloudA star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixedpoints of light.
SatelliteObjects intentionally placed into orbitTwo CubeSats orbiting around Earth after being deployed from the ISS Kibō module's Small Satellite Orbital DeployerA satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation.
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).
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.
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.*As an Amazon Associate I earn from qualifying purchases.