Presentation for the coure HIstory of Science

1. Black Holes
Kamalov Daniiar

2.  Introduction
 History of Ideas about Black Holes
 Formation
 Characteristics of BH
 Growth of BH
 Size and Amount
 Conclusion

3. - Termin “black hole” was introduced by Jonhn Wheeler
in 1967.
- Black hole - a region in the space where the
gravitational pull is so strong that neither substance
nor light can leave this area.
- Around a black hole there is a surface called an event
horizon that marks the point of no return.

4.  In the 18th century John Michell and Pierre-Simon
Laplace first mentioned about the objects with a huge
gravitation, from which even light cannot escape.
 In 1915 Albert Einstein developed the theory of
general relativity.
 Karl Schwarzschild finds black holes as a solution
to Einstein’s equations (1916)
 Robert Oppenheimer and Hartland Snyder
predict that massive stars can collapse into black
holes (1939)

5.  There are so many theories about formation
 The most obvious way of black hole - the core collapse
of massive stars at least with the size of three solar
masses. M= 1.989 × 10^30 kg. When the stars reaches
its end of life, gets crushed under its own gravity,
leaving behind a black hole.
 When a gigantic star reaches the final stage of its life
and is about to go supernova, it spends all the nuclear
fuel by then. So it stops burning and heating up and
cannot create the nuclear energy required to feed the
star.

7.  Although black holes come in a variety of masses and
sizes, their structures are all alike. A black hole's entire
mass is concentrated in an almost infinitely small and
dense point called a singularity. This point is
surrounded by the event horizon . And a rotating
black hole is surrounded by the ergosphere, a region in
which the black hole drags space itself.

10.  Once a black hole has formed, it can continue to grow
by absorbing additional matter. Any black hole will
continually absorb gas and interstellar dust from its
direct surroundings and omnipresent cosmic
background radiation.
 Another possibility is for a black hole to merge with
other objects such as stars or even other black holes

11.  There is no limit to how large a black hole can be.
However, the largest black holes we think are in
existence are at the centers of many galaxies, and have
masses equivalent to about a billion suns (i.e., a billion
solar masses). Their radii would be a considerable
fraction of the radius of our solar system.
 The size of a black hole is defined by its mass. For a
given mass, there is a length called the Schwarzschild
radius, which is proportional to the mass.

12.  There are so many black holes in the Universe that it is
impossible to count them.
 The Milky Way galaxy contains some 100 billion stars.
Roughly one out of every thousand stars that form is
massive enough to become a black hole. The nearest one is
some 1,600 light years from Earth. (1 ly=2.9 x 10^13 m)
 The most massive known black hole in the universe has
been discovered on 10 January 2008 by David Shiga.
 The black hole is about six times as massive as the previous
record holder and in fact weighs as much as a small galaxy.

13.  Из Вселенной во Вселенную
http://modcos.com/articles.php?id=44
 Черная дыра существует?
http://www.ng.ru/science/2009-01-
28/9_blackhole.html
 Black Hole
http://en.wikipedia.org/wiki/Black_hole#General_rela
tivity

14. Thank you
for your
kind attention!