Gravity well in the context of "Gravitational redshift"

A meteor, known colloquially as a shooting star, is a glowing streak of a small body (usually meteoroid) going through Earth's atmosphere, after being heated to incandescence by collisions with air molecules in the upper atmosphere, creating a streak of light via its rapid motion and sometimes also by shedding glowing material in its wake. Meteors typically occur in the mesosphere at altitudes from 76–100 kilometres (47–62 miles). The root word meteor comes from the Greek meteōros, meaning "high in the air".

Millions of meteors occur in Earth's atmosphere daily. Most meteoroids that cause meteors are about the size of a grain of sand, i.e. they are usually 1 mm (1⁄25 in) or smaller. Meteoroid sizes can be calculated from their mass and density which, in turn, can be estimated from the observed meteor trajectory in the upper atmosphere.Meteors may occur in showers, which arise when Earth passes through a stream of debris left by a comet, or as "random" or "sporadic" meteors, not associated with a specific stream of space debris. A number of specific meteors have been observed, largely by members of the public and largely by accident, but with enough detail that orbits of the meteoroids producing the meteors have been calculated. The atmospheric velocities of meteors result from the movement of Earth around the Sun at about 30 km/s (67,000 mph; 110,000 km/h), the orbital speeds of meteoroids, and the gravity well of Earth.

In astrodynamics or celestial mechanics, an elliptical orbit or eccentric orbit is an orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. Some orbits have been referred to as "elongated orbits" if the eccentricity is "high" but that is not an explanatory term. For the simple two body problem, all orbits are ellipses.

In a gravitational two-body problem, both bodies follow similar elliptical orbits with the same orbital period around their common barycenter. The relative position of one body with respect to the other also follows an elliptic orbit.

In astrodynamics or celestial mechanics a parabolic trajectory is a Kepler orbit with the eccentricity (e) equal to 1 and is an unbound orbit that is exactly on the border between elliptical and hyperbolic. When moving away from the source it is called an escape orbit, otherwise a capture orbit. It is also sometimes referred to as a ${\displaystyle C_{3}=0}$ orbit (see Characteristic energy).

Under standard assumptions a body traveling along an escape orbit will coast along a parabolic trajectory to infinity, with velocity relative to the central body tending to zero, and therefore will never return. Parabolic trajectories are minimum-energy escape trajectories, separating positive-energy hyperbolic trajectories from negative-energy elliptic orbits.

A chondrite (/ˈkɒn.draɪt/, CON-drite) is a stony (non-metallic) meteorite that has not been modified by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. Some such bodies that are captured in the planet's gravity well become the most common type of meteorite by arriving on a trajectory toward the planet's surface. Estimates for their contribution to the total meteorite population vary between 85.7% and 86.2%.

Their study provides important clues for understanding the origin and age of the Solar System, the synthesis of organic compounds, the origin of life and the presence of water on Earth. One of their characteristics is the presence of chondrules (from the Ancient Greek χόνδρος chondros, grain), which are round grains formed in space as molten or partially molten droplets of distinct minerals. Chondrules typically constitute between 20% and 80% of a chondrite by volume.

Galaxy Game is a space combat arcade game developed in 1971 during the early era of video games. Galaxy Game is an expanded version of the 1962 Spacewar!, potentially the first video game to spread to multiple computer installations. It features two spaceships, "the needle" and "the wedge", engaged in a dogfight while maneuvering in the gravity well of a star. Both ships are controlled by human players.

Created by Bill Pitts and Hugh Tuck, the initial prototype cost US$20,000 (equivalent to about $155,000 in 2024) to build. It consisted of a Digital Equipment Corporation PDP-11 minicomputer attached by a cable to a wooden console with a monitor, controls, and seats. It charged players 10 cents per game or 25 cents for three, and drew crowds "ten-deep". This was one of the first coin-operated video games; the prototype was installed in November 1971 at the Tresidder student union building at Stanford University, only a few months after a similar display of a prototype of Computer Space, making it the second known video game to charge money to play.

Spacewar! is a space combat video game developed in 1962 by Steve Russell in collaboration with Martin Graetz, Wayne Wiitanen, Bob Saunders, Steve Piner, and others. It was written for the newly installed DEC PDP-1 minicomputer at the Massachusetts Institute of Technology. After its initial creation, Spacewar! was expanded further by other students and employees of universities in the area, including Dan Edwards and Peter Samson. It was also spread to many of the few dozen installations of the PDP-1 computer, making Spacewar! the first known video game to be played at multiple computer installations.

The game features two spaceships, "the needle" and "the wedge", engaged in a dogfight while maneuvering in the gravity well of a star. Both ships are controlled by human players. Each ship has limited weaponry and fuel for maneuvering, and the ships remain in motion even when the player is not accelerating. Flying near the star to provide a gravity assist was a common tactic. Ships are destroyed when they collide with a torpedo, the star, or each other. At any time, the player can engage a hyperspace feature to move to a new and random location on the screen, though in some versions each use has an increasing chance of destroying the ship instead. The game was initially controlled with switches on the PDP-1, though Bob Saunders built an early gamepad to reduce the difficulty and awkwardness of controlling the game.