2. It was in prehistoric times when humans first noted stars
in the night sky, and it is where you can probably trace
the roots of astronomy.
In modern times Astronomy is defined as the science of
the universe outside of our planet. It is also the branch
of physical science dealing with heavenly bodies.
3. 1. Cosmology: Cosmologists study the Universe as a
whole, including its beginnings.
2. Astrometry: Astrometrists measure great distances.
3. Planetology: Planetologists study planets within our
own Solar System as well as those orbiting distant
stars.
4. Radio Astronomy: Radio Astronomers use radio-
telescopes to study the Universe.
5. Mathematical Astronomy: Mathematical
Astronomers who use numbers, calculations and
statistics to explain the universe.
4. 1. Optical Telescopes: Possess a much larger
aperture than the human eye. This means that this can
be used to collect much more of the light coming from
distant object, which greatly improves resolution and
clarity.
The Refracting Telescope
This was the earliest design and in usually formed using two
lens. The distance between two lenses, which are
commonly placed near either end of a tube, can be
adjusted to vary the resolution and magnification required.
Any light passing through the forward lenses is refracted
(bent) before being focused on the eyepiece lens.
5. 2. A Radio Telescope: produces image with aid of a
large concave mirror. The reflecting is also referred to as
the Newtonian, after the English Astronomer Isaac
Newton who first used this design to build a telescope
around 1670.
3. Spectroscope: a narrow slit that is illuminated by the
light source under study;
A collimator or tube and lens that produce a beam of
parallel light rays; either glass or prism or a diffraction
grating separate white light into its components and a
telescope for viewing a spectrum.
6. 4. Spectrograph: an instrument designed to photograph
the spectrum instead of presenting it.
5. Photometer: An instrument for measuring the
intensity of light. One of the light sources will be the
star whose brightness is to be determined, the other
will be star of known magnitude or an artificial star of
known magnitude.
6. Interferometer: an instrument used to measure the
angular diameter of the stars.
7. Thermocouple: is an extremely sensitive instrument
used to measure the heat radiated from a celestial
body.
7. 8. Comparators: comparator or a blink microscope, is
used for the examination of photographic plates taken
of the same region of the sky at different times.
9. Chronograph: is an excellent means of recording
astronomical observations accurately and permanently.
10. Coronagraph: was invented by Bernard Lyot around
1930. this device enables the corona of the sun to be
studied at anytime without waiting for the occurrence
of a solar eclipse.
8. Thales and Anaximander were the first ancient Greeks
who first recorded scientific theory on the nature of the
universe. Ptolemy described a finite universe ruled by the
mathematicians and God in which the sun, planets, and
other stars were attached to concentric spheres centered
on the Earth.
9. It was Nicolaus Copernicus who revived the Greek idea
that the Sun, and not the Earth, is the center of the
universe.
10. 1. The Big Bang Theory
This theory explains that the universe sprang into
existence as “singularity” around 13.7 billion years ago.
This force can actually squished anything that goes on its
way even light itself.
11. 2. The Oscillating Theory
The theory was credited to Richard Tolman who saw it as
a possible outcome of the Big Bang theory.
The theory emphasizes that the universe after expanding
for years will soon grow cold and dark and die an ultimate
heat death.
12. 3. The Steady State Theory
Austrian-British astronomer Hermann Bondi and the
Austrian-American astronomer Thomas Gold formulated
the theory in 1948.
The British Astronomer Fred Hoyle soon published a
different version of the theory based on his mathematical
understanding of the problem.
The big bang theory and the steady state theory were
both based on Bondi’s “cosmological principle”.it states
that the universe is on a large scale, that it looks the
same at every point.
13. A galaxy is essential an immense collection of
stars which are held together by gravity. They
range on size to shape.
14.
15. Elliptical Galaxies
Galaxies of this class have smoothly varying brightness,
with the degree of brightness steadily decreasing outward
from the center.
They appear elliptical in shape, with lines of equal
brightness which is made up of concentric and similar
ellipses.
These galaxies are nearly the entire same color, they are
somewhat redder than the Sun.
16.
17. Spiral Galaxies
These galaxies are conspicuous for their spiral-shaped
arms, which emanate from or near the nucleus and
gradually wind outward to the edge.
The nucleus of a spiral galaxy is sharp-peaked area of
smooth texture, which can be quite small or, in some
cases can make up the bulk of the galaxy
18.
19. Irregular Galaxies
Consists of grainy, highly irregular assemblages of
luminous areas.
They have no noticeable symmetry nor obvious central
nucleus, and they are generally bluer in colour than are
the arms and disks of spiral galaxies
An extremely small number of them, however, are red
have a smooth, though nonsymmetrical, shape.
20.
21. The Milky Way Galaxy
Is a spiral system consisting of several billion stars, one of
which is the Sun.
It takes its name from the Milky Way, the irregular
luminous band of stars and gas clouds that stretches
across the sky.
22.
23. Stars is a huge burning sphere of hot gas. The Sun is the
nearest to Earth and the most comprehensively studied.
The sun is just an ordinary star with ordinary size and
brightness. Since the sun itself is a star, it can be used as
reference for understanding all other the stars.
24. A star has its own brightness but does not have the
same brightness. The difference of brightness in stars
can be related to
1. The amount of light produced by stars
2. The size of each stars
3. The distance to a particular star.
25. 1. Apparent Magnitude – refers to how bright stars
appear on Earth, taking relation the effect of the
Earth’s atmosphere.
2. Absolute Magnitude – are expression of luminosity,
or the total amount of energy radiated into space
each second from the surface of the stars.
26.
27.
28. Stars have varying colors and temperature, and these
are the bases of the different natures of stars.
However, since the stars are too distant thus we can
only identify their relative brightness, the brighter
they appear the larger the image.
The color is a function of a star to determine its
relative temperature.
29. Type Color Temperature
(K)
Comment
O Bluish 30,000 – Spectrum with Ionized
80,000 helium and Hydrogen but
little else; short-lived and
rare stars
B Bluish 10,000 – Spectrum with neutral
30,000 helium, none ionized
A Bluish 7,500 – Spectrum with no helium;
10,000 strongest hydrogen, some
magnesium and calcium
F White 6,000 – Spectrum with Ionized
7,500 calcium, magnesium,
neutral atoms of iron
G Yellow 5,000 – The spectral type of the
6,000 sun, with 67 elements
K Orange – Red 3,500 – Spectrum packed with lines
5,000 from neutral metals
M Reddish 2,000 – Band spectrum of molecules
3,500
30. The Life of A Star
A star is born in a gigantic cloud of gas and dust in
interstellar space, and then spends billion of years
calmly shining while it fuses hydrogen nuclei in
core.
According to Bill W. Tillery, the life cycle of stars
are just theoretical framework based on the
outcome of studies regarding nuclear reactions,
which include nuclear fusion and fission.
31. The first stage of theoretical model of stars.
As gravity pulls the gas of a protostar together, the
density, pressure and temperature increase from
the surface down to the center.
The mass of the star can start a simple nuclear
fusion in the core.
The initial fusion combines four atoms of hydrogen
to form helium thus releasing huge amount of
energy.
32. Lesser hydrogen fusion reaction occurs, thus less
energy is released so the star begins to collapse.
The collapse heats the core, which now composed
primarily of helium and the surrounding shell still
have hydrogen.
The increase temperature causes hydrogen in the
shell to undergo fusion, and the increased release
of energy causes the outer layers of the stars to
expand.
With an increased surface area, and the amount of
radiation emitted per unit area is less, the star
acquires a property of red giant.
33. Less massive star may cool enough that the nuclei
at the surface become neutral atoms rather than
plasma.
The outer layer of stars begin to pulsate in and
out, and a violent expansion blows off the outer
layers of the stars, leaving the hot core.
The nebulae will continue to move away from the
core of the star, leaving a carbon core and helium
fusing shell begin to contract in a small, dense
white dwarf star.
34. A more massive star will definitely have different
theoretical ending. It will also contract just like
less massive star.
The heat from the star will used up all its energy,
and will no longer maintain its internal
temperature.
The star loses outward pressure of expansion
from the high temperature thus, the star will
collapse, then rebounds like a compressed spring
into catastrophic explosion called a supermova.
35. Main Sequence Stars
Red Giants
White Dwarfs
Brown Dwarfs
Variable Stars
Binary Stars
36. - is the point in a
star’s evolution
during which it
maintains a stable
nuclear reaction.
Our Sun is a main
sequence star.
37. – is a large star that is
reddish or orange in
color. It represents the
late phase of
development in a star’s
life.
The outer surface of the
star expands and cools,
giving it a reddish color.
38. Is the remnant of an
average-sized stars that
has passed through the
red giant stage of its life
after the star has used
up its remaining fuel.
The star may expel some
of its matter into space,
creating a planetary
nebula.
39. Also called as failed
star.
During the process of
star formation, some
protostars never
reach the critical
mass required to
ignite the fires of
nuclear fusion.
40. A star that changes in
brightness.
These fluctuations
can range from
second to years
depending on the
type of variable star.
Stars usually change
their brightness when
they are young and
when are old and
dying.
41. Is a system of two
stars that are
gravitationally bound
to each other.
They orbit around a
common point, called
the center of mass.
It is estimated that
about half of all stars
in our galaxy are part
of a binary system.
42.
43. 1. NEBULAR HYPOTHESIS – for many years
the nebular hypothesis was a leading theory.
According to it, the sun and its planets
supposedly condensed out of swirling eddies of
cold, dark, interstellar clouds of gas and dust.
44. 2. FISSION THEORY – the “fission theory says
that our sun burst one day, and all our planets came
from it. Then the moons shot out from each planet,
stopped, turned sideways and began circling the
planets they came out of.
3. CAPTURE THEORY – the “capture theory”
says that our planet and moons were wandering
around in space and the planets were captured by
the gravity of our sun, and the moons were captured
by the planets.
45. 4. ACCRETION THEORY – the “accretion
theory” says that our planets and moons were
wandering around in space and the planets were
captured by the gravity of our sun, and the moons
were captured by the planets.
5. PLANETARY COLLISION THEORY – the
“collision theory” of the origin our moon theorizes
that our world is said to have collided with a small
planet. The resulting explosion threw off rocks which
formed our orbiting moon.
46. 6. STELLAR COLLISION THEORY - the
“collision theory” of the origin of the entire solar
system suggests that our planets, moons, and sun all
spun off from a collision between stars.
7. GAS CLOUD THEORY – the “gas cloud
theory” of our planets and moons teaches that gas
clouds were captured by our sun, which then
mysteriously formed themselves at a distance into
planets and moons.
47. The Laws of Planetary Motion
First Law:
The orbits of the planets are ellipse with the Sun at one
focus of the ellipse.
The sun is not at the center of the ellipse, but is instead
at one focus (generally there is nothing at the other focus
of the ellipse). The planet then follows the ellipse in its
orbit, which means that the Earth-sun distance is
constantly changing as the planet goes around its orbit.
For purpose of illustration we have shown the orbit as
rather eccentric; remember that the actual orbits are
much less eccentric than this.
48. The line joining the planet to the Sun and planet
sweeps out equal areas in equal times, so the planet
moves faster when it is nearer the Sun. Thus, a
planet executes elliptical motion with constantly
changing angular speed as it moves about its orbit.
The point of nearest approach of the planet to the
Sun is termed aphelion. Hence, by Kepler’s second
law, the planet moves fastest when it is near
perihelion and slowest when it is near aphelion.
49. Kepler’s Third Law implies that the period for a
planet to orbit the Sun increase rapidly with the
radius of its orbit. Thus, we find that Mercury, the
innermost planet, (Pluto) requires 248 years to do
the same.
50. The Sun is at the center of our solar system. Sun’s
structure consists of from inner to outer elements –
core (nuclear fusion), radiative zone, convection
zone, photosphere, chromosphere, and corona.
Some of the Sun’s features are sunspots
(photosphere), solar flares, coronal loops, and
prominences (chromosphere and corona).
52. The Photosphere
The deepest layer of the sun you can see is the
photosphere.
The word “photosphere” means “light sphere”. It
is called the “surface” of the Sun because at the
top of it, the photons are finally able to scape to
space.
53. The photosphere is about 500 kilometers thick.
By analysing light from the photosphere with a
spectrograph, astronomers can tell that the Sun is
consist of hydrogen and helium.
54. Sunspots are cooler regions on the photosphere.
Since they are 1000-1500 K cooler than the rest of
the photosphere, they do not emit as much light and
appear darker . They can last a few days to a few
months.
55. During solar eclipse a thick layer can be seen at the
edge of the dark Moon. This colorful layer is called
the chromosphere (it means “color sphere”). The
chromosphere is only
2000 to 3000 kilometers
thick.
56. Solar prominence refers to a phenomenon
astronomically which involves dense ionized clouds of
gas, otherwise known as plasma, which comes our
from the sun and are detained in place by its
magnetic field. They are sculpted into vast loops of
arches by magnetic fields over sunspot group.
The gas may splatter down
into the photosphere as
coronal rain or erupt into
space.
57. Solar flares are violent explosions in the chomosphere
above sunspot groups; are caused by a release of
magnetic energy. They send out bursts of high-energy
particles and radiation that can interface with radio
communications on Earth when they strike the
ionosphere – the electrically charged layer of Earth’s
atmosphere.
Flares can endanger astronauts in space.
59. When the new Moon covers up the photosphere during a
total solar eclipse, a pearly-white corona around the dark
Moon is seen. This is the complex upper atmosphere of the
Sun. It has a very high temperature, of one to two million
Kelvin. Despite its high temperature, it has a low amount of
heat because it is so fragile.
The corona is known to be very hot because it has ions with
many electrons removed from the atoms. At high
temperatures, the atoms collide with each other with such
energy to eject electrons. This process is called ionization.
62. The energy of the sun comes from the core innermost
layer of the sun. The material in the core is firmly
attached and has very high temperature, which is
about 15 million degrees Kelvin.
64. The convective zone of the Sun is plasma-
made part. Plasma is a “gas” that conducts
electrical currents. The plasma in the
convective zone is mainly made up of
hydrogen (70℅ by mass), helium (27.7℅ by
mass) plus small quantities of carbon,
nitrogen and oxygen.
66. A non luminous celestial body bigger than an
asteroid or comet, light up by luminosity from star,
such as the sun, is called a planet.
Planets are classified into two, these are terrestrial
and gas planets.
67. Terrestrial is derived from Latin word terra,
meaning ground or soil.
Are described as the four planets in the solar
system that are closest to the sun, Mercury, Venus,
Earth, Mars.
These four planets are composed primarily of rock
and solid surfaces.
68. GAS PLANETS
Jupiter, Saturn, Neptune, Uranus are referred to as Jovian
or gas planets.
It is much larger than terrestrial planets and composed
mainly of gas and liquid.
69.
70. The closest planet to the sun.
It is a little and infertile planet.
It has thousand of impact craters.
It has no atmosphere that greatly affects its surface
temperature.
It revolves around the sun at an average distance of
about 36 million miles (58 million kilometers), compared
with about 93 million miles (150 million kilometers) for
earth.
Mercury moves around the sun faster than any other
planet.
The density of mercury is slightly a smaller amount than
the Earth’s density.
It has less mass than earth.
71.
72. It is the Earth’s “twin” because the two planets are so
alike in size.
The diameter of Venus is about 7,520 miles (12,100
kilometers), approximately 400 miles (644 kilometers)
smaller than that of the Earth.
It takes about 225 Earth days, or about 71/2 months,
to go around the sun once, compared of 365 days, or
one year
The mass of Venus is about 4/5 that of the Earth.
Venus has smaller amount of density than the Earth.
A fraction of Venus would weigh a little than an equal-
sized part of the Earth.
73.
74. Earth ranks fifth in size among the nine planets.
Its diameter is 8,000 miles (13,000 kilometers).
Earth takes 24 hours to turn completely around on its
axis so that the sun is the same place in the sky.
Earth takes 365 days 6 hours 9 minutes 9.54 seconds to
round the sun.
75.
76. Is the fourth planet from the sun.
Named for the ancient Roman god of war
Is one of Earth’s “next-doors neighbors” in space.
4.6 billion years old
Mars is about 128,390,000 miles (206,620,000
kilometers) or as much as about 154,860,000 miles
(249,230,000 kilometers) from the sun.
It revolves around the sun once every 687 Earth days;
this is what they call Martian year.
Martian day is 24 hours 39 minutes 35 seconds long.
77.
78. The chief of the gaseous giants and second of the
greater planets, is the biggest planet in solar system,
Jupiter.
Over 11 times the diameter of the Earth and has a
mass 2.5 times that all of the planets combined.
It revolves around the sun in a slightly elliptical (oval-
shaped) orbit.
It takes 9 hours 56 minutes to spin around once on its
axis, compared within 24 hours for Earth.
The density of Jupiter is about ¼ that of Earth.
79.
80. The second largest planet and the second gaseous
planet is Saturn.
It rotates faster than any other planet except Jupiter.
Rolls around once only in 10 hours 39 minutes,
compared to about 24 hours, or one day, for the Earth.
It takes about 10,759 days, or 29 ½ Earth years, to go
around the sun, compared with 365 days, or one year,
for Earth.
Has a lower density than any other planet.
81.
82. Is the seventh planet from the sun.
The farthest planet that can be seen without a
telescope.
It revolves around the sun in an elliptical (oval-shaped)
orbit in 30,685, or 84 Earth years.
Rotates on its axis and it takes 17 hours 14 minutes to
spin around once in its axis.
Uranus mass is only about 1/20 as big as that of the
largest planet, Jupiter
83.
84. One of the two planets that cannot be seen without
telescope.
30 times as far from the sun as in Earth.
It goes around the sun once in about every 165 Earth
years.
Spins around once in about 16 hours and 7 minutes.
85.
86. Dwarf planet that orbits the sun.
It lies on region known as the Kuiper belt.
39 times as far from the sun as Earth is.
It come closer to the sun than Neptune’s orbit for
about 20 years.
Pluto entered Neptune’s orbit on Jan. 23,1979, and
remained there until Feb. 11, 1999
87. The Moon is Earth natural satellite and the fifth largest
satellite in the Solar System.
The Moon makes a complete orbit around the Earth every
23.7 days, and the periodic variations in the geometry of the
Earth-Moon-Sun system are responsible for the lunar phases
that repeat every 29.5 days.
88.
89. NEW MOON
The Moon’s
unilluminated
side is facing
the Earth.
The Moon is not
Visible (except
during solar eclipse).
90. The Moon appears to be
partly but less than one-half
illuminated by direct sunlight.
The fraction of the Moon’s
disk that is illuminated I
increasing.
91. One-half of the Moon appears to be illuminated
by direct sunlight.
The fraction of the Moon’s disk that is
illuminated is increasing.
92. The Moon appears to be more than one-half but not
fully illuminated by direct sunlight.
The fraction of the
Moon’s disk that is
illuminated is increasing.
93. The Moon’s illuminated side is facing the Earth. The Moon
appears to be completely by direct sunlight.
94. The Moon appears to be more than one-half but
not fully illuminated by direct sunlight.
The fraction of the Moon’s disk that is
illuminated is decreasing.
95. One-half of the Moon appears to be illuminated by direct
sunlight.
The fraction of he Moon’s disk that is illuminated is
decreasing.
96. eclipse occur when the Earth, Sun and Moon are in a line.
If the Moon is in-between the Earth and the Sun, it blocks
the view of the Sun from some parts of the Earth, and its
produce a solar eclipse. If the Earth is between the Sun
and Moon, the Earth block the light from the Sun before if
can get to the Moon. Since moonlight is just the light the
Moon reflects from the Sun, this will darken the Moon, and
we get lunar eclipse. An eclipse is consist of a darker
shadow, or umbra and a lighter region, the penumbra or
the lighter shadow.
97. Whether it is the Moon between the Earth and Sun, or
the other way around, the phenomenon is basically the
same: the body in the middle casts a cone shadow, and if
the outer body happens to move into this cone, we have
an eclipse.
It actually consists of a darker cone, or umbra, where no
sunlight reaches, and a lighter region, the penumbra,
where only some of the sunlight is blocked.
98. A solar eclipse occurs when the Moon is directly between
the Earth and Sun. this is the most spectacular kind,
where the day changes into darkness and one can see the
stars in plain day surrounding the dark disk of the Moon.
99. 1. Total Solar Eclipse occur when the umbra of the Moon’s
shadow touches a region on the surface of the Earth.
2. Partial Solar Eclipse occur when the penumbra of the
Moon’s shadow passes over a region on the Earth’s
surface.
3. Annular Solar Eclipse occur when a region on the
Earth’s surface is in line with the umbra, but the
distances are such that the tip of the umbra does not
reach the Earth’s surface.
100. A lunar eclipse is a celestial that occurs when the Earth
blocks all or part of the sun’s rays, preventing them
from reaching the moon and thus creating a shadow
across the moon.
A lunar eclipse can happen between two and four times
per year.
101. 1. Penumbral Lunar Eclipse
The Moon passes through Earth’s penumbral shadow.
These events are of only academic interest because they
are subtle and hard to observe.
102. 2. Partial Lunar Eclipse
A portion of the Moon passes through Earth’s umbral
shadow.
These events are easy to see, even with the unaided eye.
103. The entire Moon passes through Earth’s umbral
shadow.
These events are quite striking due to the Moon’s
vibrant red color during the total phase (totality).
104. The word “tides” is a generic term used to define the
alternating rise and fall in sea level with respect to the
land, produce by a gravitational attraction of the moon
and the sun.
To a much smaller extent, tides also occur in large
lakes, the atmosphere, and within the gravitational
forces of the moon and sun.
105. Tides are created because the Earth and the
moon are attracted to each other, just like
magnets are attracted to each other.
The moon tries to pull at anything on the Earth
to bring it closer.
The Earth is able to hold onto everything except
the water.
106. SPRING TIDES
Spring tides are especially strong tides. They occur
when the Earth, the Sun and the Moon are in a line.
The gravitational forces of the Moon and the Sun both
contribute to the tides.
Spring tides occur during the full moon and the new
moon
107. Neap tides are especially weak tides. They occur when
the gravitational forces of the Moon and the Sun are
perpendicular to one another.
Neap tides occur during quarter moons.
