Means of rapid egress from a building, primarily intended for use in case of fire. Building codes define an exit as an enclosed and protected path of escape in the event of a fire, leading from an exit access through a combination of corridors, stairways, and doors to an exit discharge at an exterior court or public way. The term fire escape usually refers to open iron or steel balconies with steep stairways on the outside of buildings; often a retrofit of older buildings, these are rare in new construction. Other means of escape are by balconies leading to adjacent buildings, or through chutes, often used in hospitals.

Learn more about fire escape with a free trial on Britannica.com.

Speed sufficient for a body to escape from a gravitational centre of attraction without accelerating further. It decreases with altitude and equals the square root of 2 (about 1.414) times the speed needed to maintain a circular orbit at the same altitude. At the surface of Earth, disregarding atmospheric resistance, escape velocity is about 6.96 mi/second (11.2 km/second). Escape velocity from the surface of the Moon is about one-third of this.

Learn more about escape velocity with a free trial on Britannica.com.

Type of activity, exhibited by animals exposed to adverse stimuli, in which the tendency to flee or to act defensively is stronger than the tendency to attack. Vision is the sense that most often produces avoidance behaviour (e.g., small birds react to the sight of an owl), but sound (e.g., a warning cry) may do so as well.

Learn more about avoidance behaviour with a free trial on Britannica.com.

"Escape!" is a science fiction short story by Isaac Asimov. It was first published as "Paradoxical Escape" in the August 1945 issue of Astounding Science Fiction and reprinted as "Escape!" in the collections I, Robot (1950) and The Complete Robot (1982).

Chapter 7

Many research organizations are working to develop the hyperspace drive. US Robots are approached by their biggest competitor with plans for a working hyperspace engine that allows humans to survive the jump (a theme which would be further developed in other stories). But they are wary because, in performing the calculations, their rival's (non-positronic) supercomputer destroyed itself.

US Robots find a way to feed the information to their own computer, a positronic one known as The Brain (which is not a robot in the strictest sense of the word, as it doesn't move), without the same thing happening. The Brain then directs the building of a hypership.

Powell and Donovan board the ship, and the ship takes off without their being initially aware of it. They also find that The Brain has become a practical joker; it hasn't built any manual controls for the ship, no showers either and it only supplies tinned beans and milk for the crew to survive on.

Eventually, the ship does successfully return to Earth after a hyperspace jump, and Susan Calvin discovers what has happened. A hyperspace jump causes the crew of the ship to cease existing for a brief moment, which is a violation of the First Law (albeit temporary) and this frightens the AI of "The Brain" into irrational, childish behavior as a means of coping.

Major theme

This story again relies on the differences in interpretation of the Laws of Robotics between the human members of US Robots and their mechanical creations. The important factor in this robot is its personality; it allows the supercomputer to calculate the answer to the hyperspace problem, but causes it to behave immaturely as an idiot savant when confronted with the issues of human death.