The document discusses various celestial bodies and phenomena visible in the night sky, such as stars, the moon, planets, and constellations. It provides detailed information about the solar system, including the characteristics of each planet, their orbits, and notable features like moons and rings. Additionally, it covers concepts like asteroids, comets, meteors, and the behavior of light years, aiding in understanding the vastness and dynamics of space.

2. Night sky
The term night sky refers to
the sky as seen at night. The
term is usually associated with
astronomy, with reference to
views of celestial bodies such as
stars, the Moon, and planets
that become visible on a
clear night after the Sun has
set.

3. Note : Moon is the brightest object in the

4. What are stars ?
A huge ball of gas held together by
gravity. The central core of a star is
extremely hot and produces energy.
Some of this energy is released as
visible light, which makes
the star glow. ... Our Sun, the center
of our solar system, is a yellow star of
average temperature and size.

6. Pole Star
A pole star is a visible star,
preferably a prominent one, that is
approximately aligned with the
Earth's axis of rotation; that is,
a star whose apparent position is
close to one of the celestial poles,
and which lies approximately
directly overhead when viewed
from the Earth's North Pole or
South Pole.

8. What is light Year ?
A light year is a way of
measuring such large distance.
That doesn't make much sense
because "light year" contains the
word "year," which is normally a
unit of time. Even so, light years
measure distance•The nearest star to the earth is sun
.
•The second nearest star to the

10. What are celestial objects ?
A natural object which is located
outside of Earth's atmosphere,
such as the Moon, the Sun, an
asteroid, planet, or star.

11. The Moon
A moon is defined to be a celestial body
that makes an orbit around a planet,
including the eight major planets, dwarf
planets, and minor planets. A moon may
also be referred to as a natural satellite,
although to differentiate it from other
astronomical bodies orbiting another
body, e.g. a planet orbiting a star, the
term moon is used exclusively to make a
reference to a planet’s natural satellite.
Distance from Moon to Earth is
3,84,365(approx).

15. Distance to Earth: 384,400 km
Radius: 1,737 km
Gravity: 1.622 m/s²
Orbital period: 27 days
Age: 4.53 billion years
Orbits: Earth
A super moon is the coincidence of a
full moon or a new moon with the closest
approach the Moon makes to the Earth on its
elliptical orbit, resulting in the largest apparent
size of the lunar disk as seen from Earth. The
technical name is the perigee- syzygy of the
Earth–Moon–Sun system. In that day moon will
be 14 % more bigger and 30% more brighter.

18. Phases Of Moon
The lunar phase or phase of
the moon is the shape of the
illuminated (sunlit) portion of
the Moon as seen by an observer
on Earth. The lunar phases change
cyclically as the Moon orbits the
Earth, according to the changing
positions of the Moon and Sun
relative to the Earth.

20. What is Constellation ?
A group of stars forming a
recognizable pattern that is
traditionally named after its
apparent form or identified
with a mythological figure. Ex.
Ursa Major ,Orion, Leo Major ,
Draco

21. One of the most famous
constellations which you
can see during summer
time in the early part of
the night is Ursa major.
Orion is other well –
known constellation that
can be seen during winter
in the late evenings. It is
one of the most
magnificent constellation
in in the sky. Orion is also
called Hunter .

22. Cassiopeia is another
prominent constellation
in the northern sky. It
is visible during the
winter in the early
part night . It looks like
a distorted W or M

23. Sirius Star
Sirius is a star system and the
brightest star in the Earth's night
sky. With a visual apparent
magnitude of −1.46, it is almost
twice as bright as Canopus, the next
brightest star. The name "Sirius" is
derived from the Ancient Greek
Σείριος (Seirios), meaning "glowing"
or "scorcher".

25. The solar system
A solar system is defined as the
collection of a star and all the
objects that revolve around it.
The solar system that Earth
belongs to is composed of the sun,
eight planets, dwarf planets,
asteroids and comets etc.

27. Table of Representing different planets according to their relative sizes

28. The Sun
Sun is the chief of the solar system. It is
approximately 30,000 light years from the center
of our drive to Milky way Galaxy is and it is
situated in a corner.
The sun is a gaseous sphere, in which
71% hydrogen, 26.5% helium and other
element are 2.5%.
The central part of the Sun is called the core,
which contains thermal 1.5 * 10 raised to power 7
degree Celsius is the Sun's outer surface
temperature of 6000 degree Celsius.

29. Age of sun is 5 billion years .
A time to give by sun energy
in the future 10 raised to
power 11 years.
The time to reach sunlight to
the earth is 8 minute 16.6 second.

32. The Planets
Technically, there was never a
scientific definition of the term
Planet before 2006. When the
Greeks observed the sky thousands
of years ago, they discovered
objects that acted differently than
stars. These points of light seemed
to wander around the sky
throughout the year. We get the
term "planet" from the Greek word

33.  Planet is a body that orbits
the Sun, is massive enough for
its own gravity to make it
round, and has "cleared its
neighborhood" of smaller
objects around its orbit.

35. What Is Orbit ?
An orbit is a regular, repeating path that one
object in space takes around another one. An
object in an orbit is called a satellite. A satellite
can be natural, like Earth or the moon. Many
planets have moons that orbit them. A satellite
can also be man-made, like the International
Space Station.
Planets, comets, asteroids and other objects in
the solar system orbit the sun. Most of the
objects orbiting the sun move along or close to an
imaginary flat surface. This imaginary surface is
called the ecliptic plane.

36. Period Of Rotation
In astronomy, the rotation period
of a celestial object is the time
that it takes to complete one
revolution around its axis of
rotation relative to the background
stars.

37. Mercury (Budh)
Mercury is the smallest and
innermost planet in the Solar
System. Its orbital period (about 88
Earth days) is less than any
other planet in the Solar System.
Seen from Earth, it appears to move
around its orbit in about 116 days.
It has no known natural satellites.
Distance from sun to mercury is
57.91 million km.

38. Mercury is the closest planet to
the Sun and due to its proximity it is
not easily seen except during twilight.
For every two orbits of the Sun,
Mercury completes three rotations
about its axis and up until 1965 it was
thought that the same side of Mercury
constantly faced the Sun. Thirteen
times a century Mercury can be
observed from the Earth passing
across the face of the Sun in an event
called a transit, the next will occur on

39. Diameter: 4,879 km
Mass: 3.30 x 10^23 kg
(5.5% Earth)
Moons: None
Orbit Distance: 57,909,227 km
(0.39 AU)
Orbit Period: 88 days
Surface
Temperature:
-173 to 427°C
First Record: 14th century BC
Recorded By: Assyrian
astronomers

42. Venus (Shukra)
Venus is the second planet from
the Sun and is the second brightest
object in the night sky after the Moon.
Named after the Roman goddess of love
and beauty, Venus is the second
largest terrestrial planet and is
sometimes referred to as the Earth’s
sister planet due the their similar size
and mass. The surface of the planet is
obscured by an opaque layer of clouds
made up of sulphuric acid.Distance from sun to Venus

43. Diameter: 12,104 km
Mass: 4.87 x 10^24 kg
(81.5% Earth)
Moons: None
Orbit Distance: 108,209,475 km
(0.73 AU)
Orbit Period: 225 days
Surface
Temperature:
462 °C
First Record: 17th century BC
Recorded By: Babylonian
astronomers

46. Phases of Venus
The phases of the
planet Venus are the different
variations of lighting seen on the
planet's surface, similar to lunar
phases. The first recorded
observations of them were
telescopic observations by
Galileo Galilei in 1610.

48. EARTH(Prithvi)
Earth is the third planet from
the Sun and is the largest of
the terrestrial planets. The Earth is
the only planet in our solar system not
to be named after a Greek or Roman
deity. The Earth was formed
approximately 4.54 billion years ago
and is the only known planet to
support life.
Distance from sun to Earth is 149.6 million km

49. Equatorial
Diameter:
12,756 km
Polar Diameter: 12,714 km
Mass: 5.97 x 10^24 kg
Moons: 1 (The Moon)
Orbit Distance: 149,598,262 km (1
AU)
Orbit Period: 365.26 days
Surface
Temperature:
-88 to 58°C

52. Mars(Mangal)
Mars is the fourth planet from
the Sun and is the second smallest
planet in the solar system. Named
after the Roman god of war, Mars is
also often described as the “Red
Planet” due to its reddish appearance.
Mars is a terrestrial planet with a thin
atmosphere composed primarily of
carbon dioxide.
Distance from sun to Mars is
227.9 million km

53. Equatorial Diameter: 6,792 km
Polar Diameter: 6,752 km
Mass: 6.42 x 10^23 kg (10.7%
Earth)
Moons: 2 (Phobos & Deimos)
Orbit Distance: 227,943,824 km (1.52 AU)
Orbit Period: 687 days (1.9 years)
Surface Temperature: -153 to 20 °C
First Record: 2nd millennium BC
Recorded By: Egyptian astronomers

56. The planet Jupiter is the fifth planet
out from the Sun, and is two and a
half times more massive than all the
other planets in the solar
system combined. It is made primarily
of gases and is therefore known as a
“gas giant”. 1300 earth could Fit in
the Jupiter.
Jupiter (Brhispati)
Distance from sun to Jupiter is 778.5 million km

57. Equatorial Diameter: 142,984 km
Polar Diameter: 133,709 km
Mass: 1.90 × 10^27 kg (318 Earths)
Moons: 67
(Io, Europa, Ganymede & Callist
o)
Rings: 4
Orbit Distance: 778,340,821 km (5.20 AU)
Orbit Period: 4,333 days (11.9 years)
Effective Temperature: -148 °C
First Record: 7th or 8th century BC
Recorded By: Babylonian astronomers

60. Saturn(Shani)
Saturn is the sixth planet from the Sun
and the most distant that can be seen with
the naked eye. Saturn is the second
largest planet and is best known for its
fabulous ring system that was first
observed in 1610 by the astronomer Galileo
Galilei. Like Jupiter, Saturn is a gas giant
and is composed of similar gasses including
hydrogen, helium and methane.
Distance from sun to Saturn is 1.429 billion km

61. Equatorial Diameter: 120,536 km
Polar Diameter: 108,728 km
Mass: 5.68 × 10^26 kg (95 Earths)
Moons: 62
(Titan, Enceladus, Iapetus & Rhea)
Rings: 30+ (7 Groups)
Orbit Distance: 1,426,666,422 km (9.54 AU)
Orbit Period: 10,756 days (29.5 years)
Effective Temperature: -178 °C
First Record: 8th century BC
Recorded By: Assyrians

64. Uranus (Arun)
Uranus is the seventh planet from
the Sun. It’s not visible to the naked
eye, and became the first planet
discovered with the use of a
telescope. Uranus is tipped over on
its side with an axial tilt of 98
degrees. It is often described as
“rolling around the Sun on its side.”Distance from sun to Uranus is 2.871 billion km

65. Equatorial Diameter: 51,118 km
Polar Diameter: 49,946 km
Mass: 8.68 × 10^25 kg (15 Earths)
Moons: 27 (Miranda, Titania, Ariel,
Umbriel & Oberon)
Rings: 13
Orbit Distance: 2,870,658,186 km (19.19 AU)
Orbit Period: 30,687 days (84.0 years)
Effective Temperature: -216 °C
Discovery Date: March 13th 1781
Discovered By: William Herschel

68. Neptune(Varun)
Neptune is the eighth planet from
the Sun making it the most distant in
the solar system. This gas giant planet
may have formed much closer to the
Sun in early solar system history
before migrating to its present
position.
Distance from sun to 4.498 billion km

69. Equatorial Diameter: 49,528 km
Polar Diameter: 48,682 km
Mass: 1.02 × 10^26 kg (17 Earths)
Moons: 14 (Triton)
Rings: 5
Orbit Distance: 4,498,396,441 km (30.10 AU)
Orbit Period: 60,190 days (164.8 years)
Effective Temperature: -214 °C
Discovery Date: September 23rd 1846
Discovered By: Urbain Le Verrier & Johann Galle

72. Some Other Members Of a Solar System
 Asteroid
Asteroids are small, rocky solar system bodies that populate
interplanetary space out to the orbit of Jupiter. There are millions
of them, and they are often grouped by their composition. The
planetary science community refers to them as minor planets, a
general term applied to solar system bodies smaller than moons.
Asteroids are mainly made of materials left over from the
formation of the inner solar system words. Most of them orbit the
Sun between Mars and Jupiter, although there are groups of them
that orbit closer. Asteroids come in three composition classes. C-
types (chondrites) are made of clay and silicate rocks. S-types are
the so-called “stony” asteroids and are made mostly of silicate
rocks and nickel-iron mixtures. M-types are metallic nickel-iron.
These categories indicate how far from the Sun they formed in the
early solar system.

73. The best-known asteroids are 1 Ceres, which
is 952 kilometers across, 2 Pallas (with a
diameter of 544 kilometers), and 4 Vesta
(roughly 580 km across). These are rocky
minor planets, and astronomers have observed
them since the 1800s. Ceres is a
differentiated asteroid. That means it has a
rocky core and a icy outer crust. It might
have an internal ocean. Pallas has a very
irregular shape, and may be what’s left of an
early protoplanet. Vesta is very bright and is
likely the leftover of a rocky protoplanet.
Famous Asteroids

75. Asteroid Belt
The asteroid belt is the
circumstellar disc in the Solar
System located roughly between the
orbits of the planets Mars and
Jupiter. It is occupied by numerous
irregularly shaped bodies
called asteroids or minor planets.

77. Comets
A comet is a very small solar system body made mostly of ices
mixed with smaller amounts of dust and rock. Most comets are no
larger than a few kilometers across. The main body of the comet
is called the nucleus, and it can contain water, methane, nitrogen
and other ices.
When a comet is heated by the Sun, its ices begin to sublimate
(similar to the way dry ice “fizzes” when you leave it in sunlight).
The mixture of ice crystals and dust blows away from the comet
nucleus in the solar wind, creating a pair of tails. The dust tail is
what we normally see when we view comets from Earth.

78. A plasma tail also forms when
molecules of gas are “excited” by
interaction with the solar wind. The
plasma tail is not normally seen with
the naked eye, but can be imaged.
Comets normally orbit the Sun, and
have their origins in the Oort Cloud
and Kuiper Belt regions of the outer
solar system.

79. Well-known comets include the non-periodic
comets Hale-Bopp (C/1995 O1), Hyakutake
(C/1996 B2), McNaught (C2006 P1), and Lovejoy
(C/2011 W3). These flared brightly in our skies
and then faded into obscurity.
In addition, Comet Shoemaker-Levy 9 (D/1993
F2) was spotted after it had broken up after a
close call with Jupiter. (The D in its proper
designation means it has disappeared or is
determined to no longer exist). More than a year
later, the pieces of the comet crashed into
Jupiter.
Famous Comets

80. The periodic Comet Halley
(1P/Halley) is the most famous in
history. It returns to the inner
solar system once every 76 years.
Other well-known periodic comets
include 2P/Encke, which appears
ever 3.3 years and 9P/Tempel
(Tempel 2), which was visited by
the Deep Impact and Stardust
probes, and makes perihelion
around the Sun every 5.5 years.

82.  Meteors And Meteorites
A small body of matter from outer
space that enters the earth's
atmosphere, becoming
incandescent as a result of friction
and appearing as a streak of light.

84. Meteorites
A piece of rock or metal that has fallen
to the earth's surface from outer space
as a meteor. Over 90 per cent of
meteorites are of rock while the
remainder consist wholly or partly of iron
and nickel.

86. Meteor Showers
A number of meteors that appear
to radiate from one point in the
sky at a particular date each
year, due to the earth regularly
passing through them at that
position in its orbit.

88. Famous Meteorites
iii. The Allende Meteorite
iv. The Fukang Meteorite
i. The Hoba Meteorite
ii. The Willamette Meteorite

89. Artificial Satellites
Artificial satellites are human-built
objects orbiting the Earth and other
planets in the Solar System. This is
different from the natural satellites,
or moons, that orbit planets, dwarf
planets and even asteroids.

90. 1.Aryabhata launched on 19.04.1975 was the First
Indian satellite.
2.BhaskaraI launched on 07.06.1979 was the First
experimental remote sensing satellite.
3.BhaskaraII launched on 20.11.1981 was the
Second experimental remote sensing satellite
similar to Bhaskara1.
4.Ariane Passenger (APPLE)launched on 19.06.1981
was the First experimental communication
satellite.
5.Rohini Technology launched on 10.08.1979 was
Intended for measuring inflight performance of
first experimental flight of SLV3,the first Indian
launch vehicle

91. Aryabhatta
Bhaskara - 1

92. Bhaskara - 2
Ariane
Passenger

93. Rohini Technology

94.  Extras
Q. What are Black Hole ?
Ans. Black holes are among the strangest things in
the universe. They are massive objects – collections
of mass – with gravity so strong that nothing can
escape, not even light. The most common types of
black holes are the stellar-mass and super massive
black holes. Stellar-mass black holes are created
when massive stars explode, leaving behind a black
hole with the mass of just a few suns. Super massive
black holes exist in the hearts of galaxies and usually
contain the mass equivalent of millions of suns.

97. Famous Black Holes
Cygnus X-1: a stellar-mass black hole and x-ray source that lies
some 6,500 light-years away. It is a binary system that
contains a blue supergiant variable star and the x-ray source
thought to be the black hole.
Sagittarius A*: the supermassive black hole at the heart of
the Milky Way Galaxy. It lies in the direction of the
constellation Sagittarius. This black hole contains the mass of
about 4 million suns.
M87: this elliptical galaxy has a 3.5 billion solar-mass black
hole at its heart. The black hole is surrounded by a disk of
superheated material and has a jet of superheated material
streaming away from the black hole that extends across 5,000
light-years from the galaxy’s core.
Centaurus A: this galaxy, which lies in the direction of the
constellation Centaurus, is a giant spiral galaxy with an
incredibly active nucleus. It contains a 55 million solar-mass
black hole at its heart, with two jets of material that stream
away from the galaxy at about half the speed of light across a
million light-years of space.

98. Facts About Black Holes
The massive gravitational influence of a black hole distorts space
and time in the near neighbourhood. The closer you get to a black
hole, the slower time runs. Material that gets too close to a black
hole gets sucked in and can never escape.
Material spirals in to a black hole through an accretion disk — a
disk of gas, dust, stars and planets that fall into orbit the black
hole.
The “point of no return” around a black hole is called the “event
horizon”. This is the region where the gravity of the black hole
overcomes the momentum of material spinning around it in the
accretion disk. Once something cross the event horizon, it is lost
to the pull of the black hole.
Black holes were first proposed to exist in the 18th century, but
remained a mathematical curiosity until the first candidate black
hole was found in 1964. It was called Cygnus X-1, an x-ray source
in the constellation Cygnus.
Black holes do not emit radiation on their own. They are detected
by the radiation given off as material is heated in the accretion

99. How Black Holes are formed
Black holes are created when a large
star collapses under the force
of gravity having run out of nuclear
fuel, collapsed core of a giant star
forms a black hole. Stars have to be
at least 10 times larger than our sun
for their own gravity to crush them
creating super-nova.

100. Dwarf Planet
There are 5 officially recognized dwarf planets
in our solar system, they
are Ceres, Pluto, Haumea, Makemake and Eris.
With the exception of Ceres, which is located
in the asteroid belt, the other dwarf planets
are found in the outer solar system. There are
another 6 objects in our solar system that are
almost certainly dwarf planets and there may
as many as 10,000. Of the dwarf planets only 2
have been visited by space probes, in 2015
NASA’s Dawn and New Horizons missions
reached Ceres and Pluto respectively.

101. The largest dwarf planet in the solar
system is Pluto followed by Eris,
Makemake, Haumea, with the smallest
being Ceres. The order of the dwarf
planets from closest to Sun outwards is
Ceres, Pluto,
Haumea, Makemake, with Eris being the
furthest from the Sun.

102. Name Diameter
Distance
from the
Sun
Orbit Period
Ceres 950 km 413,700,000
km (2.77
AU)
4.6 years
Pluto 2,372 km 5,874,000,0
00 km
(39.26 AU)
246.0 years
Haumea 1,960 km -
1,518 km ×
996 km
6,452,000,0
00 km
(43.13 AU)
283.3 years
Makemake 1,434 km ×
1,422 km
6,850,000,0
00 km
(45.79 AU)
309.9 years

103. Pluto(Yam)
Discovered in 1930, Pluto is the
second closest dwarf planet to
the Sun and was at one point
classified as the ninth planet. Pluto
is the largest dwarf planet but
only the second most massive,
with Eris being the most massive.
NOTE: The new name of Pluto is
134340

104. Diameter: 2,372 km
Mass: 1.31 × 10^22 kg (0.17
Moons)
Orbit Distance: 5,874,000,000 km (39.26
AU)
Orbit Period: 246.0 years
Surface Temperature: -229°C
Moons: 5 (Charon)
Discovery Date: February 18th 1930
Discovered By: Clyde W. Tombaugh

105. Pluto is named after the Greek god of the underworld.
This is a later name for the more well known Hades and was proposed by
Venetia Burney an eleven year old schoolgirl from Oxford, England.
Pluto was reclassified from a planet to a dwarf planet in 2006.
This is when the IAU formalised the definition of a planet as “A planet is a
celestial body that (a) is in orbit around the Sun, (b) has sufficient mass
for its self-gravity to overcome rigid body forces so that it assumes a
hydrostatic equilibrium (nearly round) shape, and (c) has cleared the
neighbourhood around its orbit.”
Pluto was discovered on February 18th, 1930 by the Lowell Observatory.
For the 76 years between Pluto being discovered and the time it was
reclassified as a dwarf planet it completed under a third of its orbit
around the Sun.
Pluto has five known moons.
The moons are Charon (discovered in 1978,), Hydra and Nix (both
discovered in 2005), Kerberos originally P4 (discovered 2011)
and Styx originally P5 (discovered 2012) official designations S/2011
(134340) 1 and S/2012 (134340) 1.

106. Pluto is the largest dwarf planet.
At one point it was thought this
could be Eris. Currently the most
accurate measurements give Eris
an average diameter of 2,326km
with a margin of error of 12km,
while Pluto’s diameter is 2,372km
with a 2km margin of error.

107. Pluto is one third water.
This is in the form of water ice which is more than 3
times as much water as in all the Earth’s oceans, the
remaining two thirds are rock. Pluto’s surface is covered
with ices, and has several mountain ranges, light and
dark regions, and a scattering of craters.
Pluto is smaller than a number of moons.
These are Ganymede, Titan, Callisto, Io, Europa, Triton,
and the Earth’s moon. Pluto has 66% of the diameter of
the Earth’s moon and 18% of its mass. While it is now
confirmed that Pluto is the largest dwarf planet for
around 10 years it was thought that this was Eris.
Pluto has a eccentric and inclined orbit.
This takes it between 4.4 and 7.3 billion km from the
Sun meaning Pluto is periodically closer to the Sun than
Neptune.

108. Pluto has been visited by one spacecraft.
The New Horizons spacecraft, which was launched in
2006, flew by Pluto on the 14th of July 2015 and took a
series of images and other measurements. New
Horizons is now on its way to the Kuiper Belt to explore
even more distant objects.
Pluto’s location was predicted by Percival Lowell in 1915.
The prediction came from deviations he initially observed
in 1905 in the orbits of Uranus and Neptune.
Pluto sometimes has an atmosphere.
When Pluto elliptical orbit takes it closer to the Sun, its
surface ice thaws and forms a thin atmosphere primarily
of nitrogen which slowly escapes the planet. It also has a
methane haze that overs about 161 kilometres above the
surface. The methane is dissociated by sunlight into
hydrocarbons that fall to the surface and coat the ice
with a dark covering. When Pluto travels away from the

111. Milky Way
The Milky Way Galaxy is our home galaxy in the
universe. It is a fairly typical barred spiral with four
major arms in its disk, at least one spur, and a newly
discovered outer arm. The galactic centre, which is
located about 26,000 light-years from Earth,
contains at least one super massive black
hole (called Sagittarius A*), and is crossed by a bar.
The Milky Way began forming around 12 billion years
ago and is part of a group of about 50 galaxies called
the Local Group. The Andromeda Galaxy is part of
this group as are numerous smaller galaxies,
including the Magellanic Clouds. The Local Group
itself is part of a larger gathering of galaxies called
the Virgo Super cluster of galaxies.

112. Type: Barred Spiral
Diameter: 100,000 - 180,000 ly
Distance to Galactic
Centre:
27,000 ly
Mass: 800 - 1,500 M☉
Age: 13.6 Billion years
Number of Stars 100 - 400 billion
Constellation: Sagittarius
Group: Local Group

113. Facts About The Milky Way
The Milky Way began as a series of dense regions in the
early universe not long after the Big Bang. The first stars
to form were in globular clusters that still exist. They are
among the oldest stars formed in the Milky Way region.
The Milky Way has grown by merging with other galaxies
through time. It is currently acquiring stars from a very
small galaxy called the Sagittarius Dwarf Spheroidal, as
well as gobbling up material from the Magellanic Clouds.
The Milky Way moves through space at a velocity of about
552 kilometres per second (343 miles per second) with
respect to the Cosmic Microwave Background radiation.
The Milky Way’s central core contains a supermassive
black hole. It is commonly referred to as Sagittarius A*.
It contains the mass of about 4.3 million Suns.

114. The stars, gas and dust of the Milky
Way all orbit the centre at a rate of
about 220 kilometers per second. This
constant rate for all stars at different
distances from the core implies the
existence of a shell of dark matter
surrounding our galaxy.
Our galaxy will collide with Andromeda
Galaxy in about 5 billion years. Some
astronomers refer to our two galaxy as
a binary system of giant spirals.