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Population inversion. In physics, specifically statistical mechanics, a population inversion occurs while a system (such as a group of atoms or molecules) exists in a state in which more members of the system are in higher, excited states than in lower, unexcited energy states. It is called an "inversion" because in many familiar and commonly ...
Human overpopulation. Human overpopulation (or human population overshoot) describes a concern that human populations may become too large to be sustained by their environment or resources in the long term. The topic is usually discussed in the context of world population, though it may concern individual nations, regions, and cities.
To the right is the long tail, and to the left are the few that dominate (also known as the 80–20 rule ). In statistics, a power law is a functional relationship between two quantities, where a relative change in one quantity results in a relative change in the other quantity proportional to a power of the change, independent of the initial ...
For example, if the initial population of the assembly, N(0), is 1000, then the population at time , (), is 368. A very similar equation will be seen below, which arises when the base of the exponential is chosen to be 2, rather than e. In that case the scaling time is the "half-life". Half-life
Laser light is a type of stimulated emission of radiation. Stimulated emission is the process by which an incoming photon of a specific frequency can interact with an excited atomic electron (or other excited molecular state), causing it to drop to a lower energy level. The liberated energy transfers to the electromagnetic field, creating a new ...
In gamma-ray astronomy, gamma-ray bursts ( GRBs) are immensely energetic explosions that have been observed in distant galaxies, being the brightest and most extreme explosive events in the entire universe, [1] [2] [3] as NASA describes the bursts as the "most powerful class of explosions in the universe". [4]
1-56849-587-0. The Population Bomb is a 1968 book co-authored by former Stanford University professor Paul R. Ehrlich and former Stanford senior researcher in conservation biology Anne H. Ehrlich. [1] [2] From the opening page, it predicted worldwide famines due to overpopulation, as well as other major societal upheavals, and advocated ...
A hypernova is a very energetic supernova which is believed to result from an extreme core-collapse scenario. In this case, a massive star (>30 solar masses) collapses to form a rotating black hole emitting twin astrophysical jets and surrounded by an accretion disk. It is a type of stellar explosion that ejects material with an unusually high ...