A powerpoint presentation on comets. A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail.

1. COMETS
A journey with Comets

2. WHOA!
This presentation aims to:
1. Understand what is Comets ,
2. Explain the possible effects of comets
after hitting the earth.
3. Understand what comets are made of

3. TABLE OF CONTENTS
What is a comet?
INTRODUCTION
What comets are made
of?
COMPOSITION
What are its possible effects
if the comet hits the earth?
EFFECTS
Summary of all the details
SUMMARY
01
03
02
04

4. INTRODUCTION
01
OVERVIEW

5. COMETS is one of the celestial bodies
of the universe the light up the skies in
each time they travel to the earth. The
beauty of it also mesmerizes us as it
pass by. But have we ever ask
ourselves what does a comet contain?
What are its parts? Or what are its
effects when it lands on earth?
Lets find out!!!
INTRODUCTION

6. Comets
02
What is a comet?

7. What is a COMET?
● Comets are large objects made of dust and ice that
orbit the Sun.
● Best known for their long, streaming tails,
● streaming tails, these ancient objects are leftovers
from the formation of the solar system 4.6 billion years
ago.
COMETS

8. Comets
03
PARTS

9. WHAT ARE THE
PARTS OF
COMETS?
• NUCLEUS
• COMA
• HYDROGEN CLOUD
• DUST TAIL
• ION TAIL

10. ● The nucleus is the solid, central part of a
comet, once termed a dirty snowball or an
icy dirtball. A cometary nucleus is
composed of rock, dust, and frozen gases.
When heated by the Sun, the gases
sublimate and produce an atmosphere
surrounding the nucleus known as the
coma.
Parts of the Comet

11. ● The coma is the nebulous envelope
around the nucleus of a comet, formed
when the comet passes close to the Sun
on its highly elliptical orbit; as the comet
warms, parts of it sublimate. This gives a
comet a "fuzzy" appearance when viewed
in telescopes and distinguishes it from
stars.
Parts of the Comet

12. ● In some comets, a cloud of hydrogen
gas surrounds the coma. This hydrogen
cloud may be as big as 3 million kilometers
(about 2 million miles) across. When
comets come near the Sun, their tails
become visible because heat from the Sun
vaporizes some of the icy nucleus or head
and sunlight reflects from the vapor.
Parts of the Comet

13. ● The dust tail ranges up to 10 million km
long which is composed of smoke-sized
dust particles driven off the nucleus by
escaping gases; this is the most prominent
part of a comet to the unaided eye
Parts of the Comet

14. ● ion tail: as much as several hundred
million km long composed of plasma and
laced with rays and streamers caused by
interactions with the solar wind.
● The dust tail forms from those dust
particles and is blown back by solar
radiation pressure to form a long curving
tail that is typically white or yellow in colour.
The ion tail forms from the volatile gases in
the coma when they are ionized
by ultraviolet photons from the Sun and
blown away by the solar wind.
Parts of the Comet

15. Comets
02
Facts about Comets

16. ● Comets come from the Kuiper belt and the Oort
Cloud. These areas of space are way out in the
solar system far away from the Sun. The Oort cloud
is so far away we have never even seen it! The
comets visible from Earth are most likely ones that
came from the closer Kuiper belt which is near Pluto.
● There are millions of comets, and they are all
orbiting the Sun. Most take less than two hundred
years to do so, and others travel much slower,
potentially taking millions of years to complete an
orbit.
Facts About Comets

17. ● Comets spend most of their years in the Kuiper belt
and Oort cloud. Every now and again two comets can
crash into one another. When this happened, they often
change direction, and this can throw them out towards the
inner solar system.
● When a comet approaches the inner planets, it is
warmed by the Sun. When this happens, it begins to melt
and throws out dust and gas. This creates a head and the
tail. The tail is the part of the comet we see in the sky. The
tail always points away from the Sun. This means that
sometimes the tail is behind the comet and sometimes it in
front. It all depends on whether the comet is travelling
towards or away from the Sun.
Facts About Comets

18. ● Travelling through a comet’s tail is not
dangerous. Earth even passes through them. When this
happens, we see a meteor shower!
● The word comet comes from the Greek word Kometes
meaning long hair. This is because of how a comet’s tail
can look like long flowing locks of hair.
● Like asteroids, comets are leftovers from the formation
of the Solar System. We don’t know an awful lot about
them at this point, but scientists believe they may hold
clues to how the Solar System came to be.
Facts About Comets

19. ● The most famous comet of all time is Halley’s
Comet. Halley is a periodic comet and is visible from
Earth every 76 years and has been for centuries. It
made its last appearance in 1986. Other famous
comets include the Hale-Bopp Comet, Donati’s
comet and the Shoemaker-Levy 9 Comet.
Facts About Comets

20. Comets
04
Top 5 Comets That Has Been
Seen On Earth

21. ● After Halley’s Comet, Comet Borrelly was only the second
to be spied close-up by a spacecraft. NASA’s Deep Space
1 paid a visit in 2001 and gave researchers a detailed
glimpse of the comet’s pitch black core. Its snapshots
revealed that the rocky nucleus is shaped like a giant 8-
kilometre-long bowling pin, and the entire comet is
curiously lopsided.
● Unlike Halley’s Comet, which formed in the Oort Cloud at
the outer edges of the Solar System, Borrelly is believed to
originate in an icy cloud of rocks beyond Neptune called
the Kuiper Belt.
Top 5 Comets That Has Been
Seen On Earth

22. ● Comet Hale Bopp made its closest approach to Earth for
4000 years in January 1997. The last time the cosmic
wanderer was seen near Earth was during the Bronze age
in 2000 BC. Hale Bopp is much larger and more
spectacular than Halley’s comet. It has a nucleus up to 40
km (24 miles) in diameter and could be viewed from Earth
with the naked eye. Hale-Bopp is so bright that it was
visible from Earth as early as 1995, when it was still
outside the orbit of Jupiter.
● The advent of Hale Bopp led to a bizarre and tragic human
event – 39 members of the Heaven’s Gate cult in San
Diego, US, marked the arrival by committing suicide.
Top 5 Comets That Has Been
Seen On Earth

23. ● An icy-blue blob with a faint gas tail created the most
spectacular comet display for 20 years as Comet
Hyakutake passed just 15 million kilometres (9.3 million
miles) from Earth in March 1996. It was the closest the
comet had come to the Sun in 9000 years. The comet left
astronomers puzzled as it produced X-rays 100 times more
intense than predicted.
● The spacecraft Ulysses unintentionally passed through
Hyakutake’s tail in May 1996, showing that it as at least
570 million km (350 million miles) long – twice as long as
that of any other known comet.
Top 5 Comets That Has Been
Seen On Earth

24. ● Comet Shoemaker Levy-9 distinguished itself by breaking
into 21 pieces under the stresses of Jupiter’s gravity in
1992 and then slamming in succession into the giant planet
in 1994. The spectacular show was watched by telescopes
across Earth, in orbit and aboard the space probe Galileo.
● The impact of one fragment – around 3 km across – is said
to have yielded an explosion and fireball equivalent to 6
million megatonnes of TNT. The plume reached 22,000 km
(13,700 miles) above the cloud tops.
Top 5 Comets That Has Been
Seen On Earth

25. ● Halley’s Comet is the most famous of all comets. British
astronomer Edmund Halley was the first to realise that
comets are periodic, after observing it in 1682 and tallying
it to records of two previous comet appearances. He
correctly predicted it would return in 1757. The comet is
also though to be depicted in the 1066 Bayeux Tapestry.
● Halley’s Comet, which is 8 kilometres (5 miles) wide and 16
km (10 miles) long, travels around the Sun every 75 to 76
years in an elongated orbit. It last passed close to Earth in
February 1986.
Top 5 Comets That Has Been
Seen On Earth

26. Comets
04
Effects if it land on earth

27. IF A COMET LANDED ON
EARTH, WHAT WOULD
LIKELY HAPPEN?
If the comet is 10 kilometers
across or larger (that is, if the impact
carries an energy of more than about
100 million megatons), the
resulting global environmental
damage will be so extensive that it
will lead to a mass extinction, in
which most life forms die.

28. In this topic, we learn:
● Comets are celestial bodies that is made from ice
particles and dust
● Comets are consist of coma, nucleus, solar wind and
sunlight, comets' orbit, dust tail, ion tail
● If a comet collides with earth and has enough energy,
the living things on earth would likely to be
experiencing a global environmental trauma that will
lead to extinction.
SUMMARY

29. CREDITS: This presentation template was created by
Slidesgo, including icons by Flaticon, and infographics &
images by Freepik
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