Karl Schwarzschild devised the first general relativity model that would adequately describe a black hole in 1916.
What is Black Hole?
A black hole is an area of spacetime with such intense gravitational pull that nothing can escape from it, not even light or other electromagnetic waves. According to general relativity theory, a compact enough mass can bend spacetime into a black hole. The event horizon is the line beyond which there is no escape.
Black holes were once thought to be a mathematical curiosity, but theoretical research in the 1960s revealed that they were actually a general prediction of general relativity.
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No, not exactly. They jiggle and tremble and vibrate a lot, but
they always basically stay in very nearly the same place.
It's like if you're allowed to go anywhere you want in your jail cell,
you wouldn't exactly call that "moving about freely".
Answer:
Plane will 741.6959 m apart after 1.7 hour
Explanation:
We have given time = 1.7 hr
So if we draw the vectors of a 2d graph we see that the difference in angles is = 
Speed of first plane = 730 m/h
So distance traveled by first plane = 730×1.7 = 1241 m
Speed of second plane = 590 m/hr
So distance traveled by second plane = 590×1.7 = 1003 m
We represent these distances as two sides of the triangle, and the distance between the planes as the side opposing the angle 58.6.
Using the law of cosine,
representing the distance between the planes, we see that:

r = 741.6959 m
Ionic bonds occur when electrons are donated from one atom to another. Each type of atom forms a characteristic number of covalentbonds with other atoms. An example of that is a hydrogen atom with one electron in its outer shell forms only one bond, its out most orbital becomes filled with two electrons.
the outermost protons