Presentation about black holes

1. Black Holes
Prince Kumar
14119039

2. Contents
● Introduction
● Properties and Structure
● Formation and Evolution
● Observational Evidence
● Role of Black Holes in
the Universe

3. Introduction
A black hole is a region of
space in which gravity is so
strong that even light
cannot escape it. This
region is formed due to
huge amount of matter in
an infinitely small point.
Data Source: NASA
Image Source: geekspace.com

4. What would happen if our
sun is replaced with a black
hole of same mass???

5. Contrary to popular belief,
the solar system wouldn’t
be sucked in; a solar mass
black hole would exert no
more gravitational pull
than our sun.

6. Properties of Black Holes
● It is not mass, but their size which matters.
● They distort space as well as time.
● Gravitational Lensing
● Black Holes can grow in size by sucking matter or merging with
other black holes.
● Black Holes eventually evaporate over time.

7. Structure of Black Holes
● In layman's terms, Event
Horizon is defined as "the
point of no return".
● Singularity is a
one-dimensional point which
has infinite mass in a point
space and where the laws of
physics as we know cease to
operate.

8. Formation of Black Holes: Supernova
When a star, generally 5 or more times massive than our sun,
has its hydrogen given out, it switches to helium, then carbon,
then ultimately to iron. Now, fusion of iron doesn’t release
energy, and in a fraction of second, due to its own weight, the
star compresses into a black hole.

9. SN 1987A
Source: scienceblogs.com

10. Death of Black Holes: Hawking Radiation
● A black hole too dies with time, if it doesn’t absorb any matter for a
sufficiently long time
● Hawking showed that quantum effects allow black holes to emit
exact black body radiation. The electromagnetic radiation is produced
as if emitted by a black body with a temperature inversely
proportional to the mass of the black hole.

11. Hawking Radiation

12. Observational Evidences
● Motion Analysis of stars
around Sagittarius A*
● X-Ray Emission from
Accretion of Disk
● Gravitational Lensing
● Quasars from other
galaxies

13. 1. Accretion of Disc 2. Gravitational Lensing
Source: i.ytimg.com

14. So, are black holes like
hungry demons???

15. Role of Black Holes in the universe
● Act as energy recyclers.
● Acts as seeds of the
galaxies.
● Without black holes, the
universe would have
been entirely different.
Source: National Geographic

16. Sombrero Galaxy
Source: picsaboutspace.com

17. Milky Way from Ladakh, India
Source: cdn.c.photoshelter.com

18. Thank You