The Black Holes

Presented by: Sarita Chauhan
M.Sc. (Final) Physics
Department of Physics G.C.A
History
• In the 18th century John Michell and Pierre-Simon Laplace
first mentioned about the objects with a huge gravitat...
2

“Black

holes are exotic structures whose
gravitational fields are so powerful that they
trap everything, even light. T...
Black holes
• This can happen when a star is dying.
• Though they are black they are invisible to us.
• The density of a b...
on the basis of mass : Three classifications of
black holes
• Stellar-mass: 3 to 20 times the mass of our Sun
• Supermassi...
Mid Mass

Supermassive

Stellar mass
Formation of black holes
• The most common way for a black hole to form is
probably in a supernova, an exploding star.
• W...
Formation of black holes
• If there is enough mass, the gravity of collapsing core will
compress it so much that it can be...
5. DO ALL STARS BECOME STELLAR-MASS
BLACK HOLES?
Mass < 8 suns

Mass < 3 suns
Mass <1 sun

It all depends
on the amount
of...
Characteristics
• Although black holes come in a variety of masses and
sizes, their structures are all alike. A black hole...
Size of black holes

• The more massive a black hole is, the more
space it takes up. A typical 10-solar-mass black
hole wo...
Parts of a Black Hole
Outer event
horizon
Space-time

Inner event
horizon
Singularity

“White hole”

Space-time- the fabri...
Outer Event Horizon &
Inner Event Horizon
• Outer event horizonthe point of no return.
• As one nears the outer
event hori...
Singularity
• Scientists believe that at
the center of a black hole
lies a gravitational
singularity, a point in the
space...
Different type of black holes…..
•

Schwarzchild black holes : Don’t rotate
and have no charge.

•

Reissner – Nordstrom b...
•

Kerr black holes: rotate but have no charge.

•

Kerr – Newman black holes: Rotate and have charge.
Growth of Black Hole
• Once a black hole has formed, it can continue to grow by
absorbing additional matter. Any black hol...
2. How do we
«see»
black holes?
Nobody has
literally seen a
black hole yet,
but there are
instruments with
which
astronome...
How do we know it’s there?
Years

“Weird”
motions of
objects
nearby

supermassive black

Orbits of stars very close to the...
IF WE CAN’T SEE THEM, THEN HOW DO WE KNOW
THEY ARE THERE?

 The X-rays are sent off into space and when they strike
the m...
Accretion Disk and Plasma Jets…..
•

•
•

•

An accretion disk is a spinning gas
and matter that
a black hole attracts.
Ac...
Where are black holes located?
• Black holes are everywhere.
• There are probably millions of black holes in milky way
alo...
Falling into a black hole
 The pulling force would increase as you moved toward
the center, creating what's called a "tid...
What happens should you be sucked into a black
hole?
• Spaghettification is a theory as to what happens when
a person is s...
What happens to a spaceship that falls into a black
hole?
• We can escape from the surface of Earth in a
spaceship if the ...
The whole process, from
the time you shut off
your engines, takes just
a few minutes.

Falling into a Black Hole.
How have we existed so long if black holes are so
dangerous?

• The answer is :
1. Great distances between the stars .
2. ...
What are scientists trying to learn?
X-ray: NASA/CXC/U. Wisconsin/A.Barger
et al.; Illustrations: NASA/CXC/M.Weiss

NASA m...
Conclusion
• When we look into the Universe today, we see that pretty much every
large galaxy has a super massive black ho...
Thanks for
listening
Any
queries?????
Sarita chauhan seminar on black hole
Sarita chauhan seminar on black hole
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Sarita chauhan seminar on black hole

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search on NASA site also go through the latest news related to black holes before presenting your seminar.
many queries are asked related to black holes.
present the astronomical data's for Good delivery of seminar.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)
A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull.”
Black holes are exotic structures whose gravitational fields are so powerful that they trap everything, even light. They were first postulated by Albert Einstein's theory of general relativity.”
This can happen when a star is dying.
Though they are black they are invisible to us.
The density of a black hole is so great it would be like taking the whole Earth and crushing into a volume smaller than a 1” marble!.
Stellar-mass: 3 to 20 times the mass of our Sun

Supermassive: Black holes with millions to billions of times the mass of our Sun

Mid-mass: In between stellar-mass and supermassive.

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Sarita chauhan seminar on black hole

  1. 1. The Black Holes Presented by: Sarita Chauhan M.Sc. (Final) Physics Department of Physics G.C.A
  2. 2. History • 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)
  3. 3. 2 “Black holes are exotic structures whose gravitational fields are so powerful that they trap everything, even light. They were first postulated by Albert Einstein's theory of general relativity.” ss much ma 1 “A black hole is a region of space that has so much mass concentrated in it that there is no way for a nearby object to escape its gravitational pull.” gravity …no escape from 1. What is a black hole?
  4. 4. Black holes • This can happen when a star is dying. • Though they are black they are invisible to us. • The density of a black hole is so great it would be like taking the whole Earth and crushing into a volume smaller than a 1” marble!.
  5. 5. on the basis of mass : Three classifications of black holes • Stellar-mass: 3 to 20 times the mass of our Sun • Supermassive: Black holes with millions to billions of times the mass of our Sun • Mid-mass: In between stellar-mass and supermassive .
  6. 6. Mid Mass Supermassive Stellar mass
  7. 7. Formation of black holes • The most common way for a black hole to form is probably in a supernova, an exploding star. • When a star of about 25 times the mass of the sun ends its life, it explodes. • The outer part of the star screams outward at high speed, but the inner part of the star, i.e., core, collapses down.
  8. 8. Formation of black holes • If there is enough mass, the gravity of collapsing core will compress it so much that it can become a black hole. The black hole will have a few times mass of the sun. this is called a ‘stellar mass black hole’. • But there are also monsters, called super massive black holes. These are present in the centers of galaxies, and are huge. They can be millions or billions of times the mass of sun! these are probably formed during the formation of galaxies. In milky way we are having sagittarius A* as our supermassive black hole.
  9. 9. 5. DO ALL STARS BECOME STELLAR-MASS BLACK HOLES? Mass < 8 suns Mass < 3 suns Mass <1 sun It all depends on the amount of mass stars contain Becomes a white dwarf http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-a-black-hole-k4.html Becomes a neutron star Becomes a black hole
  10. 10. Characteristics • 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.
  11. 11. Size of black holes • The more massive a black hole is, the more space it takes up. A typical 10-solar-mass black hole would have a radius of 30 kilometers, and a million-solar-mass black hole at the center of a galaxy would have a radius of 3 million kilometers.
  12. 12. Parts of a Black Hole Outer event horizon Space-time Inner event horizon Singularity “White hole” Space-time- the fabric of both space and time
  13. 13. Outer Event Horizon & Inner Event Horizon • Outer event horizonthe point of no return. • As one nears the outer event horizon, it appears time slows down and stops altogether. • Objects start to travel at the speed of light after they reach the inner event horizon
  14. 14. Singularity • Scientists believe that at the center of a black hole lies a gravitational singularity, a point in the space-time curvature becomes infinite. • The center of the black hole is a point of infinite density and zero volume, called a singularity
  15. 15. 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.
  16. 16. • Kerr black holes: rotate but have no charge. • Kerr – Newman black holes: Rotate and have charge.
  17. 17. Growth of Black Hole • 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 omit present cosmic background radiation. • Another possibility is for a black hole to merge with other objects such as stars or even other black holes
  18. 18. 2. How do we «see» black holes? Nobody has literally seen a black hole yet, but there are instruments with which astronomers detect and study their X-ray emissions and their effects over matter. SATELLITES DETECT RADIATION ATOMS EMIT X-RAYS INTO SPACE ATOMS ARE IONIZED AND REACH A FEW MILLION KELVIN THE BLACK HOLE MOVES FASTER AND HEATS UP MATTER FALLS OR IS PULLED INTO THE BLACK HOLE http://imagine.gsfc.nasa.gov/docs/science/know_12/black_holes.html
  19. 19. How do we know it’s there? Years “Weird” motions of objects nearby supermassive black Orbits of stars very close to the center of our galaxy over a period of 14 years
  20. 20. IF WE CAN’T SEE THEM, THEN HOW DO WE KNOW THEY ARE THERE?  The X-rays are sent off into space and when they strike the matter around the black hole , it can be detected.  Binary X-ray sources are placed to find strong black hole .  Another sign of the presence of a black hole is random variation of emitted X-rays. And gravitational lensing ,accretion disks n gas jets .
  21. 21. 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.
  22. 22. Where are black holes located? • Black holes are everywhere. • There are probably millions of black holes in milky way alone, but the nearest one is discovered 1600 quadrillion Kms! • The giant black hole in the center of the galaxy is even farther away, at a distance 30,000 light years, we're in no danger of sucked in to the vortex.
  23. 23. Falling into a black hole  The pulling force would increase as you moved toward the center, creating what's called a "tidal force" on your body.  If you fell into a large enough black hole, no one outside would be able to see you, but you'd have a view of them. Meanwhile, the gravitational pull would bend the light weirdly and distort your last moments of vision.
  24. 24. What happens should you be sucked into a black hole? • Spaghettification is a theory as to what happens when a person is sucked in. What happens is the gravity of the black hole stretches your molecules so far you become as thin as a piece of spaghetti, before completely disintegrating. • The other theory is you are simply pulled apart from a tidal force that you snap apart at your weakest point before being dismantled molecule by molecule.
  25. 25. What happens to a spaceship that falls into a black hole? • We can escape from the surface of Earth in a spaceship if the spaceship is accelerated fast enough (about 11 km/sec) similarly you would need a force that could accelerate your spaceship to faster than the speed light travels to escape from a black hole - and nothing we know of can exceed the speed of light.
  26. 26. The whole process, from the time you shut off your engines, takes just a few minutes. Falling into a Black Hole.
  27. 27. How have we existed so long if black holes are so dangerous? • The answer is : 1. Great distances between the stars . 2. All the stars are orbiting the center of the Galaxy.
  28. 28. What are scientists trying to learn? X-ray: NASA/CXC/U. Wisconsin/A.Barger et al.; Illustrations: NASA/CXC/M.Weiss NASA missions continue to search for and study black holes to determine the fate of matter as it falls into black holes, how Schaller (for STScI) Credit: NASA, ESA, and A. powerful jets form, and what role black holes played in the formation of the early universe.
  29. 29. Conclusion • When we look into the Universe today, we see that pretty much every large galaxy has a super massive black hole in its heart. Even the Milky Way has a black hole at its core with a mass of four millions times that of the Sun. – Black Holes are a long way off at least 26,000 light years (260 quadrillion kilometers) – Its mass is still very small compared to the 200 billion solar masses of our galaxy so it can’t really harm us. – Even though black holes can cause death and destruction on a major scale, they also help galaxies themselves form! So we owe our existence to them. A • Black holes may be used as worm hole in future in time travel.
  30. 30. Thanks for listening
  31. 31. Any queries?????

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