1. black holes
- Utkarsh upadhyaya(2013167)
- Nikhil raj()
- Nikhil()

2. What is a BLACK HOLE…..
 Black Hole is a powerful gravity that can grab the tiniest and the largest things
of the universe.
 It is a spacetime from which gravity prevents
anything, including light from escaping.
For this reason this hole is black.
 It’s like a perfect black body in thermodynamics.
 There is a mathematically defined surface
around black hole called event horizon which
marks the point of “no return”.

3. Contributions in discovering Black Holes…..
 John Michell and Pierre-Simon Laplace in 18th century were the first to
discover some objects whose gravity fields are too strong to escape light.
 The first modern solution of general relativity that would characterize a black
hole was found by Karl Schwarzchild in 1916.
 Their interpretation as a region of space from which nothing can escape was
first published by David Finkelstein in 1958.

4. Formation of black holes…..
 Expected to form when very massive stars collapse at the end of their life cycle.
 After forming, black holes keep on expanding their size by absorbing mass from
their surroundings.
 By absorbing other stars and merging with other black holes, Supermassive
black holes of millions of solar mass may form.
 There is a general consensus that the black holes exist at the centre of galaxies.

5. Accretion Disk and Plasma Jets…..
 An accretion disk is a spinning gas
and matter that
a black hole attracts.
 Accretion disk converts matter into
energy very efficiently.
 Viscosity in the disk redistributes
angular momentum, causing material
in the disc to spiral inward
towards the singularity.
 Plasma jet is Relativistic jet that
is given off by the black holes.

6. What scientists have discovered about black
holes…….
 Scientists discovered that black holes may have a link to time interval.
 Black holes affect mass and time. Mass has no volume and time does not pass.
 Scientists have found ways to use computer to create images of black holes.

7. General information about black holes…..
 Matter falling onto the black holes can form accretion disk heated by friction,
forming some of the brightest objects in the universe.
 If there are other stars orbiting the
black holes, their orbits can be
used to determine black
holes’ mass and location.
 Astronomers have identified many stellar
black holes in the universe and established
that the core of our Milky Way galaxy
contain supermassive black holes of about 4.3 million solar masses.

8. Different type of black holes…..
 Schwarzchild black holes : Don’t rotate
and have no charge.
 Reissner – Nordstrom black holes: don’t rotate
but have charge.

9.  Kerr black holes: rotate but have no charge.
 Kerr – Newman black holes: Rotate and have charge.