Astronomy is the scientific study of celestial objects beyond Earth's atmosphere. It has split into observational and theoretical branches since the 20th century. Nicolaus Copernicus proposed a model with the Sun at the center in the 16th century, though planets still seemed to deviate from perfect circular orbits. Tycho Brahe made precise measurements, which Johannes Kepler used to discover the three laws of planetary motion, including that orbits are elliptical. Modern astronomy began with the Space Age in the 1950s with the launch of Sputnik and the space race between the USSR and US. Major events included Gagarin and Shepard's space flights and the Apollo moon landings. Theories of solar system and galaxy formation continue to be

2. Astronomy and Modern Science
Astronomy is the scientific study
of celestial objects (such as stars,
planets, comets, and galaxies) and
phenomena that originate outside
the Earth's atmosphere (such as
the cosmic background radiation).

3. Branches of Astronomy
Since the 20th century, the field of professional
astronomy split into
• observational Branches
is focused on acquiring and analyzing data,
mainly using basic principles of physics.
• Theoretical branches
is oriented towards the development of
computer or analytical models to describe
astronomical objects and phenomena.

4. The Birth of Modern Astronomy

5. Nicolaus Copernicus
• Became convinced that
Earth is a planet just like
the others known at the
time.
• He proposed a model of
the solar system with the
Sun at the center.

6. • He used circles to
represent the orbits of the
planets.
• This was not ultimately
successful as the planets
still seemed to stray from
their predicted positions,
indicating that their path
around the Sun was not a
perfect circle.

7. Tycho Brahe
• A Danish astronomer who
was noted for his precise
measurement of the
locations and orbits of
celestial bodies.
• He is most noteworthy for
his observations of Mars.

8. Johannes Kepler
• Assistant to Brahe, he
kept all of the data,
and used it to continue
making observations
after Brahe’s death.
• Discovered three laws
of planetary motion.

9. • The most important
was that the orbit of
planets are not circles
but ellipses.
• Ellipses are oval in
shape; almost like an
egg

11. ANCIENT ASTRONOMY
Astronomy is the science of understanding everything
that goes on beyond Earth’s boundaries. It is one of the
oldest of sciences. Every civilization, through antiquity to
the recent past, had stunning views of stars night after
night, as sightings of the cosmos would not have been
hampered by the light pollution and an indoor life style,
both of which hide much of the heavens from observers
today.
All over the world some sort of the understanding of the
celestial sphere was an integral part of civilization,
whether or not they opted for scientific explanations of
the observed phenomena.

12. THE SPACE AGE
The Space Age was an entirely new era ushered in by the end
of the Second World War and emerging nuclear power as well
as the beginning of the Cold War.
The Space Age began in October of 1957 when the Soviets
launched Sputnik 1, the first satellite, into space.
This was when space exploration first became possible. The
Space Age came about as the Soviet Union and the United
States started competing in arms and technology as well as to
see which country would make it into space first.
 the Space Race between the Soviets and America was a vital
part of the Space Age. About a month after the Soviets sent
Sputnik 1 into space, they sent the space dog Laika up into
orbit in Sputnik 2.

13. On 12 April 1961, the Soviet Union
successfully put a man in space.
Cosmonaut Yuri Gagarin spent 108 minutes
orbiting the Earth once in the Vostok 1
probe. Less than a month later, On 5 May,
Alan Shepard became the first American in
space. It was not until February 1962, that
an American successfully orbited the earth;
John Glenn, aboard Friendship 7 circled the
Earth 3 times.
Yuri Gagarin

14. • One of the highlights of the Space Age was the Apollo
program.
• NASA’s Apollo 8 astronauts became the
first men to leave Earth’s gravity & orbit
the Moon. The most famous of the Apollo
aircraft is Apollo 11, which was the craft
carrying Commander Neil Armstrong and
his fellow astronauts Michael Collins and
Buzz Aldrin to the Moon. On that mission,
Armstrong and Aldrin were the first
humans to land and walk on the Moon.
They were later followed by a number of
other astronauts.

15. THE SOLAR SYSTEM
The formation of the Solar System is estimated
to have begun 4.6 billion years ago with the
gravitational collapse of a small part of a giant
molecular cloud Most of the collapsing mass collected
in the centre, forming the Sun, while the rest flattened
into a proto planetary disk out of which the planets,
moons, asteroids, and other small Solar System bodies
formed.

16. End of the solar system:
• It is difficult to calculate exactly where our solar system ends. It ends at a point at
which objects are no longer affected by the sun’s gravitational pull. The farthest
reaches of the solar system are thought to be surrounded by a great halo: Oort cloud;
home to millions of comet nuclei & small icy rocks.

17. Important Theories regarding
modern Astronomy

26. Galileo Galilei (1594 – 1642)
Invented the modern view of science: Transition
from a faith-based “science” to an observation-
based science.
Greatly improved on the newly invented
telescope technology. (But Galileo did NOT invent
the telescope!)
Was the first to meticulously report
telescope observations of the sky to support
the Copernican Model of the Universe.

27. Major Discoveries of Galileo
• Moons of Jupiter (4 Galilean moons)
• Rings of Saturn

28. Major Discoveries of Galileo (2)
• Surface structures on the moon; first estimates
of the height of mountains on the moon

29. Recent works
New limit on the definition of a planet proposed
• Date: January 23, 2018
• Source: Johns Hopkins University
• Summary: A planet can be no bigger than about
10 times the size of Jupiter, an astrophysicist has
calculated.

30. Chance of Finding Young Earth-Like Planets
Higher Than Previously Thought
• June 5, 2020 — Researchers have found that the
chance of finding Earth-like planets in their
early stages of formation is much higher than
previously

31. Astronomy Bot Speeds Up Search for Jupiter's
Twins
• June 25, 2019 — Astronomers have a new tool in
their search for extraterrestrial life -- a
sophisticated bot that helps identify stars
hosting planets similar to Jupiter and

32. Astrophysicists Discover Planets in Extragalactic
Galaxies Using Microlensing
• Feb. 2, 2018 — Astrophysicists have discovered
for the first time a population of planets beyond
the Milky Way galaxy. Using microlensing -- an
astronomical phenomenon and the only known
method capable of discovering planets at truly
great distances from the Earth among other
detection techniques -- researchers were able to
detect objects in extragalactic galaxies that range
from the mass of the Moon to the mass of
Jupiter.

33. Bizarre Worlds Orbiting a Black Hole?
• Nov. 25, 2019 — Theoreticians in two different
fields defied the common knowledge that
planets orbit stars like the Sun. They proposed
the possibility of thousands of planets around a
super massive black hole.

34. Five Planets Revealed After 20 Years of
Observation
• Apr. 17, 2019 — To confirm the presence of a
planet, it is necessary to wait until it has made
one or more revolutions around its star. This can
take from a few days for the closest to the star to
decades for the

35. New Research of Oldest Light Confirms Age of
the Universe
• July 15, 2020 — New research suggest the
universe is about 13.8 billion years old,
according to researchers using observations
from the Atacama Cosmology Telescope (ACT)

36. Scientists Propose Plan to Determine If Planet
Nine Is a Primordial Black Hole
• July 12, 2020 — Scientists have developed a new
method to find black holes in the outer solar
system, and along with it, determine once-and-
for-all the true nature of the hypothesized Planet
Nine.