Characteristics

In 1915, Albert Einstein proposed his theory of general relativity. Explaining that, gravitational fields alter the very geometry of space and time. Observations from space revealed an unexpected source of X-rays coming from a previously unremarkable area of the galaxy. A massive object was the sources of this energy and Signus X1 became worldwide news. Scientist had discovered a black hole in a binary system; making this the first observation of Einsteinien black holes. And while direct observation was impossible, its existence was deducted due to the black hole's apparent gravitational effect on its companion star.

Based on Isaac Newton's laws of gravity in the 1700's scientist, began to discuss the possibility of an object so dense that it could completely capture light. Unlike Einstein, Newton drew no connection between space and gravity. He believed that gravity was a singular force that only reacted on objects.

English geologist John Michell realized that, using Newtonian physics, it would be theoretically possible for gravity to be so overwhelmingly strong and that nothing, not even light traveling at 186,000 miles an hour, could escape it. To generate such gravity, an object would have to be very massive and unimaginably dense. At the time, the necessary conditions for "dark stars" (as Michell called them) seemed physically impossible, and astronomy had not yielded any observational data. His ideas were published by the French mathematician and philosopher Pierre Simon Laplace in two successive editions of an astronomy guide.

(http://antwrp.gsfc.nasa.gov/apod/ap001210.html)

These images generated by a computer show what happens if you went too close to a black hole. The image on the right shows the effects of being close to a black hole; objects are distorted and light is bent towards you because of the intense gravity felt.