General Astronomy/Black holes/Introduction
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A black hole is an object that holds a gravitational field so powerful that nothing, not even radiation or light, can escape, after passing the event horizon (the name given to the figurative line over which the gravitational force becomes too strong to escape). The black hole is so called because, as not even light can escape its infinitely powerful gravitational pull, it is rendered invisible. In this way, black holes are undetectable, except by the trail of destruction they leave behind them, or their interaction with proximate objects.
The theory behind black holes designates that, when a certain amount of mass is present in an infinitely small region of space (referred to as a "naked singularity"), all paths through space in 4-dimensions are inwardly curved, forcibly pulling all forms of matter toward the source. Such a dense region of space, the black hole, has been predicted to form either following the collapse of a massive star, or the collision of two neutron stars. The former is, however, said to be by far the more common, considering the rarity of the latter.
Many aspects of the black hole model still pose unanswered questions, and the nature of the black hole remains largely unknown. Numerous theories as to what a black hole looks like, and what exists in the interior have been proposed, and the black hole is a regularly seen element of science fiction. Some even propose that black holes could lead to be gateways to other universes or parallel realities with radically different physical laws.
In the following topic, we'll look at these theories, while exploring what is already known about black holes, as well as the history of the concept of objects with a gravity so strong that nothing can escape. We will discuss the properties of the black hole, and the impact these properties have on the surrounding spacetime and the matter around them, and how these properties, as well as the effects they cause, can be exploited in the detection of these invisible monsters. Finally, we'll examine the terrible life of the black hole, from its birth in the blazing remains of a destroyed star to its gradual evaporation.
- Table of contents
