Holes Ginnie Baldwin PHYSICS 1050 Astronomy Fall 2011 BLACK HOLE WHAT IS A BLACK HOLE A black hole is a concentration of matter so dense that not even light can escape its gravitational pull ID: 410974
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Black Holes
Ginnie BaldwinPHYSICS 1050: AstronomyFall 2011Slide2
BLACK HOLESlide3
WHAT IS A BLACK HOLE?A black hole is a concentration of matter so dense that not even light can escape its gravitational pull.Slide4
The theory of general relativity predicts that a sufficiently compact mass will deform space time to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return. It is called "black" because it absorbs all the light that hits the horizon, reflecting nothingSlide5
SUPERMASSIVE BLACK HOLESlide6
WHAT IS A SUPERMASSIVE BLACK HOLE?Black holes come in many sizes. Astronomers believe that a “supermassive” black hole, with a mass of about 4 million Suns, lies at the center of the Milky Way galaxy.Slide7
Supermassive black holes have masses of several hundred thousand to more than ten billion solar masses. The central region of virtually every galaxy is thought to contain an object of this type. Slide8
HOW DO SUPERMASSIVE BLACK HOLES FORM?One theory is that an individual star-like black hole forms and swallows up enormous amounts of matter over the course of millions of years to produce a supermassive black hole.
Another possibility is that a cluster of star-like black holes forms and eventually merges into a single, supermassive black hole. Slide9
ARE BLACK HOLES DANGEROUS TO EARTH?Black holes certainly can be dangerous, but to us here on earth black holes don’t present an immediate threat. The nearest one is 1600 light years away, far too far to exert any gravitational pull
.…But what about wandering black holes?Slide10
WANDERING BLACK HOLESSlide11
WHAT ARE WANDERING BLACK HOLES?Quite literally, a wandering black hole is a black hole that is not stationary and is in constant movement. Michio Kaku, professor of theoretical physics at City University of New York, stated, “In the year 2000, all hell broke loose. At that point, we had conclusive evidence that there are wandering black holes -- nomads, renegades -- right next to us in our own backyard of a galaxy."Slide12
ARE WANDERING BLACK HOLES A THREAT TO THE EARTH?If a wandering black hole were to come near to Earth, the results would be catastrophic. The gravitational pull from the black hole would do one of three things: swallow up the Earth, throw the Earth off its axis and out of the solar system or towards the sun.
However, the odds are highly unlikely that such an occurrence would ever take place. Slide13
IN CONCLUSIONA black hole is a region of space having a gravitational field so intense that no matter or radiation can escape.By absorbing other stars and merging with other black holes,
supermassive black holes of millions of solar masses may be formed.Wandering black holes exist, however, are not much of a threat to Earth at the present time.