Black hole

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Black hole

  1. 1. PRESENTED BY: S.HABINAYA.
  2. 2.    A black hole is an object with such powerful gravity that nothing can escape from it, including light. It is result of deformation of space time caused by the very compact mass. In black hole there is an undetectable surface which marks the point of no return, called an “Event Horizon”. It is called “Black” because it absorb all the light that hit it reflect nothing, just like the perfect black body.
  3. 3.  The idea of a body so massive that even light could not escape was first put forward by geologist John Michell in 1783.  In 1935, Subrahmanyan Chandrasekhar also prove the black star by the theory of “ White dwarfs” which led to an understanding of mass limits that decide whether a star will die as a white dwarf, neutron star or black star.  The modern theory of black bole is proposed by Stephen Hawking.
  4. 4.     “Normal Sized” Black Holes Microscopic (Primordial) Sized Super-Massive Black Holes (On the order of millions to billions of Solar Masses) (Estimated 3 million solar masses for Milky Way Black Hole)
  5. 5.   There are many theories to that question. Most common theory is where a colossal star with a mass of more than 3 times the sun’s reaches the end of its life, gets crushed under its own gravity, leading behind a compact black hole When a gigantic star reaches the final stage at its life and is about to go supernova, it spends all the nuclear fuel by then. So it stop burning and heating up and cannot create the nuclear energy required to feed the star.
  6. 6.  Although black come in a variety of masses and sizes, their structures are all alike. A black hole’s entire mass is concentrated in an almost infinite small and dense point called a singularity. This point is surrounded by the event horizon. And a rotating black hole is surrounded by the ergo sphere, a region in which the black hole drags space itself. The radius of the black hole is called “schwarzschild radius”.
  7. 7.  Once a black hole has formed, it can continue to grow by absorbing additional matter. Any black hole will continuously absorb gas and interstellar dust from its direct surroundings and omnipresent cosmic background radiation.
  8. 8.  Black hole are so massive that nothing, not even light, can escape its path. So that means that even stars and asteroids or much less any thing in its path would get sucked up and crushed into absolutely nothing. So yes there are dangerous.
  9. 9.  According to the general relativity there is no limit to the size of a black hole. But a full of how gravity works must also include quantum mechanics and such a theory has yet to be constructed. Some hits from recent work on this theory suggest that a black hole can be no smaller than about “10 to the (-33) cm in radius”. 0.000000000000000000000000000000001 cm.
  10. 10.   There is no limit to how large a black hole can be. However, the largest black hole are thick are in existence are at the centres of many galaxies, and have masses equivalent to about a billion sun(i.e., a billion solar masses). Their radii would be considerable fraction of the radius of our solar system. The size of a black hole if defined by its mass. For a given mass, there is a length called the Schwarzschild radius which is proportional to the mass.
  11. 11.    There are so many types of black hole are in the universe they are impossible to count it. The milky way galaxy contain about 100 billion stars. Roughly out of that 1000 stars that firm is massive enough to become a black hole. The nearest one is some 1,600 light year from earth. The most massive black hole was discovered by hubble space telescope at 10th january 2008. Its mass is equivalent to small galaxy.
  12. 12.   Along with Thomas Hertlog at CERN, in 2006, Hawking proposed a theory of “Top down Cosmology” Which say that the universe had 0 unique initial state Stephan Hawking proposed that microscopic Black hole formed in huge explosion that gave birth to the universe.
  13. 13. All Black Holes Evaporate over time due to Hawking Radiation  Eventually the Universe will have no matter in a cold dark death and all there will be left is radiation.  Evaporation Time: 1 * 10^-7 (M/M )^3 Years On order of 1* 10^20 years  sun

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