Artificial satellites are human-made objects that orbit Earth and other planets. They are used to study planets, help with communications, and observe the universe. Sputnik 1 was the first artificial satellite launched in 1957. Other notable satellites include Luna 2, the first to reach the moon, and Vanguard 1, the longest-living satellite still in space. Space probes like Voyager 1 have explored other planets and space beyond our solar system. The International Space Station is a modular space station in low Earth orbit operated by various space agencies. There are two main theories for the origin and evolution of the universe: the Big Bang theory and the Steady State theory.

3. Artificial Satellites
 Artificial satellites are
human-built objects
orbiting the Earth and
other planets in the Solar
System.
 Artificial satellites are
used to study the Earth,
other planets, to help us
communicate, and even
to observe the distant
Universe

4. First Artificial Satellite in Space
Sputnik 1 was the first artificial satellite to be put into Earth's
orbit. It was launched into an elliptical low Earth orbit by
the Soviet Union on 4 October 1957. It was launched during
the International Geophysical Year from Site No.1/5, at the
5thTyuratam range, in Kazakh SSR (now at the Baikonur
Cosmodrome). The satellite travelled at 29,000 kilometers
(18,000 mi) per hour, taking 96.2 minutes to complete an
orbit, and emitted radio signals at 20.005 and
40.002 MHz .The signals continued for 22 days until the
transmitter batteries ran out on 26 October 1957.Sputnik
1 burned up on 4 January 1958, as it fell from orbit upon
reentering Earth's atmosphere, after travelling about 60
million km (37 million miles) and spending 3 months in
orbit.

5. Sputnik 1

6. Other Artificial Satellites
Luna 2 (E-1A series) was the
second of the Soviet Union's
Luna programme spacecraft
launched to the Moon. It was
the first spacecraft to reach the
surface of the Moon. It
successfully impacted with the
lunar surface east of Mare
Imbrium near the craters
Aristides, Archimedes, and
Autolycus. It is launched on
September 12, 1959 at
06:39:42

7. Vanguard 1
Vanguard 1 was the
4th artificial Earth
satellite and first
satellite to be solar
powered. The
spacecraft weights
1.47 kg. It is launched
on March 17, 1958 at
12:15:41UTC. This
holds record for being
in space longer than
any other man made
objects

8. First Human in Space
On April 12,1961, Russian
cosmonaut Yuri Gagarin
became the first human in
space, making a 108-
minute orbital flight in his
Vostok 1 spacecraft.

9. Alan Bartlett Shepard,
Jr. was an American naval
aviator, test pilot, flag
officer, and NASA
astronaut 1961 became
the second person, and
the first American on the
surface of the moon,. This
Mercury flight was
designed to enter, but not
to achieve orbit. He is the
fifth person to walk on the
Moon and the only
(Alan Shepard planting American Mercury Astronaut walked
Flag on Moon’s Surface.) on the moon.

10. Apollo 11
Apollo 11 was the
spaceflight which landed
the first humans, Neil
Armstrong and Edwin
"Buzz" Aldrin, Jr, on
Earth's Moon on July 20,
1969, at 20:17:39 UTC. The
United States mission is
considered the major
accomplishment in the
history of space
exploration.

11. Space Probes
A space probe is a scientific space exploration mission
in which a spacecraft leaves Earth and explores space.
It may approach the Moon, enter interplanetary, flyby
or orbit other bodies, or approach interstellar space.
Space probes are a form of robotic spacecraft .

12. Example of Space Probes
Voyager 1
Voyager 1 is a 733-kilogram
probe launched on
September 5, 1977. It is
currently still operational,
making it the longest-lasting
mission of NASA. It is the
farthest human-made object
from the Earth. As of
2010,Voyager is over 17
tetrameters (1.7 x 1013 meters
or 1.7 x 1010 kilometers), 10.5
million miles from the sun.

13. Mars Exploration Rover
 NASA's Mars
Exploration Rover
Mission (MER) is an
ongoing robotic space
mission involving two
rovers, Spirit and
Opportunity exploring
to planet Mars. It is
sending of two rovers—
MER-A Spirit and MER-B
Opportunity to explore
the Martian surface and
geology.

14. Skylab
 Skylab was a space
station launched and
operated by NASA, the
space agency of the
United States. Skylab
orbited the Earth from
1973 to 1979, and
included a workshop, a
solar observatory, and
other systems.

15. International Space Station
 The International Space
Station (ISS) is a habitable
Artificial satellite in low Earth
orbit. It follows the Salyut,
Almaz, Skylab and Mir
stations. The ISS is a
modular structure whose first
component was launched in
1998. Like many artificial
satellites, can be seen from
Earth with naked eye

16. Theories
 Big Bang Theory-
It states that the
Universe was once in
an extremely hot and
dense state which
extend rapidly. The
expansion caused the
universe cool and
resulted in its present
continuously
expanding state.

17. Steady State Theory
 In cosmology, the Steady
State theory (also known
as the Infinite Universe
theory or continuous
creation) is a model
developed in 1948 by Fred
Hoyle, Thomas
Gold, Hermann Bondi and
others as an alternative to
the Big Bang theory
(known, usually, as the
standard cosmological
model). In steady state
views, new matter is
continuously created as the
universe expands, so that
the perfect cosmological
principle is adhered to.