A brief presentation regarding heavenly bodies. Basic knowledge of Earth, Moon and Sun. The Solar System, Stars and Galaxies.

3. Early Astronomy
• Human beings are curious creatures. They
have a natural desire to seek explanations for
the existence of things. To the first people to
exist, much of what existed on Earth would
have been a mystery to them. The objects in
space that we now know as stars, planets,
moons and comets would have completely
baffled them. But by looking at them and
trying to understand them, these early human
beings would become the first astronomers.

5. Pictures Depicting Early
Astronomy

6. Eratosthenes
Eratosthenes was a
Greek
mathematician
who is famous for
his work on prime
numbers and for
measuring the
diameter of the
earth

8. The Moon does not
produce any light of its own—it
only reflects light from the Sun. As
the Moon moves around the Earth,
we see different parts of the near
side of the Moon illuminated by
the Sun. This causes the changes in
the shape of the Moon that we
notice on a regular basis, called the
phases of the Moon. As the Moon
revolves around Earth, the
illuminated portion of the near
side of the Moon will change from
fully lit to completely dark and
back again.

10. Rotation is when a planet or moon turns all the
way around or spins on its axis one time. The
axis of rotation is an imaginary line going from
the north pole to the south pole. When a planet
or moon travels once around an object this is
considered a revolution. On Earth, a rotation is
pretty short - it happens once a day! It is the
rotation that makes the sun appear to come up
in the morning and set at night. On Earth, a
revolution is quite a bit longer - one year!

13. The moon is the easiest celestial object to
find in the night sky — when it's there. Earth's only
natural satellite hovers above us bright and round
until it seemingly disappears for a few nights. The
rhythm of the moon's phases has guided humanity
for millennia — for instance, calendar months are
roughly equal to the time it takes to go from one
full moon to the next.

14. An eclipse is an astronomical event that
occurs when an astronomical object is
temporarily obscured, either by passing
into the shadow of another body or by
having another body pass between it and
the viewer.

15. A solar eclipse occurs
when the new moon
passes directly
between the Earth and
the Sun. This casts a
shadow on the Earth
and blocks our view of
the Sun.
Solar Eclipse

16. A total solar eclipse occurs when the
Moon's shadow completely blocks
the Sun. When only a portion of the
Sun is out of view, it is called a
partial solar eclipse. Solar eclipses
are rare events that usually only last
a few minutes. That is because the
Moon's shadow only covers a very
small area on Earth and Earth is
turning very rapidly. As the Sun is
covered by the moon's shadow, it
will actually get cooler outside. Birds
may begin to sing, and stars will
become visible in the sky. During a
solar eclipse, the corona and solar
prominences can be seen.

18. A lunar eclipse occurs when the full moon moves through the
shadow of the Earth. This can only happen when the Earth is
between the Moon and the Sun and all three are lined up in the
same plane, called the ecliptic. The ecliptic is the plane of Earth's
orbit around the Sun. The Earth's shadow has two distinct parts:
the umbra and the penumbra. The umbra is the inner, cone
shaped part of the shadow, in which all of the light has been
blocked. The outer part of Earth's shadow is the penumbra where
only part of the light is blocked. In the penumbra, the light is
dimmed but not totally absent. A total lunar eclipse occurs when
the Moon travels completely in Earth's umbra. During a partial
lunar eclipse, only a portion of the Moon enters Earth’s umbra. A
penumbral eclipse happens when the Moon passes through Earth’s
penumbra. The Earth's shadow is quite large, so a lunar eclipse
lasts for hours and can be seen by anyone with a view of the Moon
at the time of the eclipse.

20. After World War II drew to a close in the
mid-20th century, a new conflict began.
Known as the Cold War, this battle
pitted the world’s two great powers–the
democratic, capitalist United States and
the communist Soviet Union–against
each other. Beginning in the late 1950s,
space would become another dramatic
arena for this competition, as each side
sought to prove the superiority of its
technology, its military firepower and–
by extension–its political-economic
system.

21. The Apollo program, also known as
Project Apollo, was the third
United States human spaceflight
program carried out by
the National Aeronautics and
Space Administration(NASA),
which accomplished landing the
first humans on the Moon from
1969 to 1972.

23. Our solar system consists of
an average star we call the
Sun, the planets Mercury,
Venus, Earth, Mars, Jupiter,
Saturn, Uranus, Neptune,
and Pluto. It includes: the
satellites of the planets;
numerous comets,
asteroids, and meteoroids;
and the interplanetary
medium.

24. Ptolemy was the most
influential of Greek
astronomers and
geographers of his time.
He propounded the
geocentric theory that
prevailed for 1400 years.
Claudius Ptolemy

25. Galileo Galilei, was an
Italian astronomer,
physicist, engineer,
philosopher, and
mathematician who
played a major role in
the scientific revolution
during the Renaissance.
Galileo Galilei

26. Tycho Brahe, born Tyge
Ottesen Brahe, was a
Danish nobleman known
for his accurate and
comprehensive
astronomical and
planetary observations.
He was born in Scania,
then part of Denmark,
now part of modern-day
Sweden.
Tycho Brahe

27. Johannes Kepler December
27, 1571 – November 15,
1630) was a German
Mathematician, astronomer,
and astrologer. A key figure in
the 17th century scientific
revolution, he is best known
for his laws of planetary
motion.
Johannes Kepler

28. English physicist and
mathematician Sir Isaac
Newton, most famous for
his law of gravitation,
was instrumental in the
scientific revolution of
the 17th century.
Iaac Newton

29. It is often said that the Sun is
an "ordinary" star. That's
true in the sense that there
are many others similar to it.
But there are many more
smaller stars than larger
ones; the Sun is in the top
10% by mass. The median
size of stars in our galaxy is
probably less than half the
mass of the Sun.

30. The inner planets (in order of
distance from the sun, closest
to furthest) are Mercury,
Venus, Earth and Mars. After an
asteroid belt comes the outer
planets, Jupiter, Saturn, Uranus
and Neptune. The interesting
thing is, in some other
planetary systems discovered,
the gas giants are actually quite
close to the sun.

31. Asteroids are small, airless rocky
worlds revolving around the sun
that are too small to be called
planets. They are also known as
planetoids or minor planets. In
total, the mass of all the asteroids
is less than that of Earth's moon.
But despite their size, asteroids can
be dangerous. Many have hit Earth
in the past, and more will crash
into our planet in the future.

32. A meteor is a bright
streak of light in the sky
(a "shooting star" or a
"falling star") produced
by the entry of a small
meteoroid into the
Earth's atmosphere.

33. The outer planets are those
planets in the Solar
System beyond the asteroid
belt, and hence refers to the
gas giants, which are in order
of their distance from the
Sun: Jupiter is the largest
planet in the Solar System. It
has four very large satellites.

34. The astronauts had to
use special tools to
collect rock samples on
the Moon because they
could not bend over in
their spacesuits.

36. Lenses form images by refraction
and are typically made of either glass
or plastic. They are ground so that
their surfaces are either segments of
spheres or planes. If a lens is convex
or converging, it takes parallel light
rays from a distant object and bends
them so that they converge to a
single point called the focal point.
The distance from the lens to the
focal point is called the focal length
of the lens.

38. The earliest telescopes, as well
as many amateur telescopes
today, use lenses to gather more
light than the human eye could
collect on its own. They focus the
light and make distant objects
appear brighter, clearer and
magnified.

39. A refracting or refractor
telescope is a type of
optical telescope that uses a lens
as its objective to form an image
(also referred to a
dioptric telescope). The refracting
telescopedesign was originally
used in spy glasses and
astronomical telescopes but is also
used for long focus camera lenses.

41. A reflecting
telescope (also called a
reflector) is an
optical telescope which
uses a single or
combination of curved
mirrors that reflect light
and form an image.

43. As everybody knows distances in
astronomy are vast with many
people struggling to understand
the extremely large numbers
involved and the methods
Astronomers use to calculate
distances. It must be said here
that there is no single method
able to be used to calculate the
distance to the entire
Astronomical phenomena that
have been discovered.

45. When the light from a
galaxy which is moving
away from you is observed
the wavelength of the
observed light appears
longer, it moves towards
the red end of the
spectrum. This is
called RED SHIFT.

48. Red shift supports the big bang theory.
The big bang theory is that the
universe began from a very small initial
point. The universe then expanded
from that point to give us the universe
we see today.
The light from distant galaxies is red
shifted (this tells us the galaxies are
moving away from us) and the further
away the galaxy the greater the red
shift (this tells us that the more distant
the galaxy the faster it is moving).

52. A star is a luminous sphere
of plasma held together by
its own gravity. The
nearest star to Earth is the
Sun. Other stars, mostly in
the Milky Way, are visible
from Earth during the night,
appearing as a multitude of
fixed luminous points due to
their immense distance.

53. Life Cycle of Stars

55. A system of millions
or billions of stars,
together with gas
and dust, held
together by
gravitational
attraction.