10,000+ B.C.
During the Paleolithic period, early
people kept track of the moon's phases
by engraving lines onto animal bones.
It has also been suggested that certain
4,900 B.C
star patterns were memorialized the The earliest Sun observatory
same way. Astronomy has been used
to predict the cycle of the seasons for
has been built using four
agricultural purposes, measuring time concentric circles, a
and measuring direction. mound, and two wooden
stakes. The observatory
1,100 to 3,000 B.C. enabled people to measure
Astronomers named many constellations the Sun's path during a solar
and identified planets. People started to year accurately.
use sundials, and sailors used pole stars for
navigation. Constellations were invented;
Zodiac constellations marked the Sun,
moon, and planets' path throughout the
year. People used clay tablets to record
the earliest astronomical records and star
catalogs, recording the position of planets
800 B.C.
and solar eclipse. The Stonehenge was Yajnavalkya proposed a
built; it is a sacred place of worship and is
aligned to mark the summer and winter heliocentric concept of the
solstices. The earliest record of a solar Universe where the Earth is
eclipse was made.
spherical, and the Sun is at
the center of the spheres.
611 to 547 B.C.
Anaximander made the first detailed
maps of the Earth and the sky. He knew
that the Earth was round, and he believed
that it was free-floating and unsupported.
He also measured the Earth's
circumference and put forward the idea
that celestial bodies make full circles in
their orbits and conceptualize space has
600 to 130 . . B C
Greeks develop astronomy from being
depth. Thales traveled Mesopotamia and
an observational science related to
Egypt and brought astronomical records
back to Greece. Thales believed that the religion into a theoretical science
Earth is a disk floating on an endless about the structure of the Universe.
ocean. It says that he correctly predicted Aristarchus suggests the Earth revolves
a solar eclipse. around the Sun. He provides the first
estimation of Earth-Sun distance.
569 to 475 . . B C
Eratosthenes of Cyrene, a Greek
polymath, measures the
Pythagoras put forward the idea circumferences of the Earth.
that the Universe is made of crystal
spheres that encircled the Earth.
According to him, the Sun, moon,
planets, and stars traveled in 450 . B C
Anaxagoras suggested that the stars
separate spheres, and when the
are suns, similar to our own but located
spheres touch each other, a "music at such vast distances that we cannot
of the spheres" can be heard. feel their heat back on Earth.
Anaxagoras attracted a lot of
attention and disapproval from
384 to 322 . . B C
Aristotle proved that the Earth is spherical and
religious groups, and he was
subsequently exiled from Athens.
believed that it was at the center of the
Universe. He believed that if the Earth revolved
around the Sun, we should see the stars shift
position throughout the year. Since he did not
have the technology to detect this shift, he
concluded that the Earth rested at the center of
the Universe. According to him, the Sun, planets,
and stars were located in spheres that revolved
around the Earth.
350 to 230 B.C.
Eudoxus proposed the concept of transparent
spheres supporting the bodies visible in the
heavens. Aristarchus suggested a heliocentric
190 to 120 B.C.
theory of the Universe. He proposed that the Earth
and planets revolved around a stationary sun; the
Sun was in the center of the Universe. His theory Antikythera mechanism, an ancient
was considered far too radical; it was not popular. astronomical computer, was constructed in
It was nearly 1800 years before it was finally ancient Greece. It was capable of
accepted. He also attempted to measure relative
predicting star and planet positions and
distances between the Earth and the Sun and the
lunar and solar eclipses. Hipparcos
Earth and the moon. He used a reasonable
method to measure this. However, He had not very completed and compiled the first known
accurate results due to the lack of technological star catalog to organize astronomical
equipment. objects and came up with the scale to
define stars' brightness. He measured the
distance from the Earth to the moon to be
50 to 45 B.C. 29.5 earth diameters. His most significant
discovery was the precession of the Earth's
The Maya introduces a calendar with a axis, caused by the Sun and moon's
cycle of fifty-two years, known as the gravitational pull.
Calendar Round. Julius Caesar's new
calendar is introduced when its
predecessor has become out of step with
the seasons by three months.
85 to 165 A.D.
Claudius Ptolemy used Hipparchus's extensive
observations to develop a model that predicted
the Sun, moon, planets, and stars' movements. His
780 to 850 A.D. model was called the Ptolemaic system; it
visualized an Earth-centered Universe and
assumed that all astronomical objects move at
Al-Khwarizmi developed a mathematical
constant speeds in circular orbits. The circle was
device completely in words based on the
considered the perfect shape; regardless of the
system on Indian numbers borrowed by the evidence against circular orbits, Ptolemy built his
Arabs. His work was translated into Latin model to fit this idea. The Ptolemaic model is one
and served as the European introduction to of the longest upheld scientific histories and was
the Indian number system, complete with the cornerstone of astronomy for 1500 years.
Ptolemy refined the original geocentric model in
its concept of zero. He performed detailed
his masterpiece entitled "Almagest," which listed
calculations of the Sun, moon, and planets'
48 constellations and charted the stars and
positions and did several eclipse planets' motions. He also published his theory of
calculations. He also constructed a table of the Earth-centered Universe.
the latitudes and longitudes of different
cities and landmarks, forming the basis of
an early world map. 1048 to 1420 . . A D
Omar Khayyam compiled many
astronomical tables and performed a
reformation of the calendar. Ulugh-Beg,
1473 1543 . .
prince of Turkestan, builds a great
observatory and prepares tables of planet
to A D and star data.
Nicolaus Copernicus began a new era of
astronomy when he concluded that the Sun was
the center of the Universe instead of the Earth.
Copernicus felt that the Ptolemaic system was
contrived but kept the orbits circular when he
revised that model. His idea was not popular with
1546 to 1601 . . A D
Tycho Brahe built an observatory where he made
the church. However, several astronomers helped
to prove this model of the Universe more the most accurate astronomical observations. His
accurately portray reality. Modern astronomy observatory contained sophisticated equipment
began to take shape when Copernicus published for mapping star positions. He made detailed
his masterpiece "De Revolutionibus Orbium records of his observations and findings. He
Coelestium," which used empirical evidence to believed that the Universe was a blend of
revive Aristrachus' heliocentric view of the Ptolemaic and Copernican models. Then he
Universe. created his own model in which the planets orbit
1564 1642 . .
the Sun, and the Sun orbits the Earth.
to A D
1571 1630 . .
Galileo Galilei heard about the invention of the
telescope and built one for himself. He used the
telescope to make some incredible to A D
astronomical observations and make several Johannes Kepler used Tycho Brahe's collection of
stunning discoveries. Galileo saw the craters, astronomical records and used them to develop
mountains, and valleys of the moon and planetary motion laws. He believed in the Copernican
noticed the huge number of stars making up model of the Universe. However, Kepler found it difficult to
fit Tycho's observations of mars into the model with a
the milky way, kept precise records of sunspot
circular orbit. He compiled accurate and comprehensive
activity and the phases of Venus, and observations of the planets' positions to further credit the
discovered four orbiting Jupiter. These four Copernican system over the Ptolemaic one. He also built
moons are called Galilean Moons today. He the uniborg. Johannes used the idea of elliptical orbits to
also publicized the fact that other astronomical describe the motions of the planets, which became
bodies were revolving around something other known as Kepler's first law. His second law states that a
than the Earth. Galileo attempted to defend line from the Sun to a planet sweeps out equal areas in
equal amounts of time. The third law states that the
the heliocentric model of the Universe, which
square of the number of years of a planet's orbital period
landed him in direct conflict with the church.
is equal to the cube of that planet's average distance
from the Sun.
1605 to 1608 A.D.
Johannes Kepler discovered that the planets
orbit about the Sun in an elliptical and not
circular motion and then proposed his three
planetary motion laws. Dutch spectacle maker
Hans Lippershey invented the refractor
1625 to 1712 A.D.
telescope. Giovanni Cassini discovered the division
in Saturn's rings, which is now known as
the Cassini division. He also found four
1643 to 1727 A.D.
Isaac Newton developed extensive mathematics to
moons orbiting the Sun and measured
the periods of rotation of mars and
describe the astronomical models of Copernicus and Jupiter. He also calculated the distance
Kepler. His theory of Universal Gravitation was the
from the Earth to the Sun and is only 7%
foundation of Kepler's laws of planetary motion. Though
it went further, Newton showed the laws governing out.
astronomical bodies were the same laws governing
motion on Earth's surface. Isaac Newton also invented
1730 to 1822 A.D.
the first reflecting telescope that used a curved mirror
instead of a lens to look further into space. He later
published his book "Philosophiae Naturalis Principia
Mathematica." He agreed that the Earth rotated around Charles Messier published a list of 110
the Sun and explained the reasons behind Kepler's three
laws. Isaac Newton also established the law of universal
astronomical objects that must never be
gravitation, which started in a New Age of physics and mistaken for comets. Galaxies, nebulae,
Enlightenment. Using a homemade telescope, and star clusters are among the fascinating
Christiaan Huygens accurately describes the rings of
sights visible through small telescopes. The
Saturn and discovers the planet's largest moon, Titan.
M objects are used to classify the brightest
stars in the sky. William Herschel discovered
1747 to 1826 A.D. Uranus and two of its moons. He also found
two more moons from Saturn and certain
Johann Bode made a law that is mainly asteroids and compiled a database of
used to calculate the distances between 2,500 astronomical objects. He discovered
the planets and the Sun. He was able to Mars' polar ice caps, which are now being
calculate that there should be another observed by several satellites in the hopes
planet between Mars and Jupiter, which is of revealing the presence of water on the
where the asteroid belt is located, using planet today.
his own law. Joseph von Fraunhofer
discovered that dark lines in the spectrum
1836 1941 . .
were coming from the Sun. He calculated
the positions of over 300 of these lines, to A D
resulting in creating a wavelength norm. Joseph Lockyer discovered the element Helium during
Pierre-Simon Laplace publishes his nebular the time he was studying the atmosphere of the Sun.
He kept meticulous records of sunspot activity and
hypothesis, arguing that the planets
studied solar flares and prominences, among other
formed from a mass of incandescent gas things. Lockyer led many tours to locations where solar
and proposed the concept of Black Holes. eclipses were expected to be visible and occurred
and were also one of the very first
archaeoastronomers. He wrote an infamous book
1868 1938 . .
called 'The Dawn of Astronomy,' which looks into
ancient cultures' astronomy, particularly Egypt. Johann
to A D Galle discovered the Neptune. Annie Cannon's
spectra were used to classify the stars. She classified
George Hale helped explain an important
over 400,000 stars into the system that we use today (O
phenomenon present in the Sun by B A F G K M). She also ended up discovering 300
discovering that sunspots have localized variable stars. She undoubtedly paved the way for
magnetic fields. Henceforth, his most women entering the astronomical field.
1873 1967 .
incredible legacy was being able to found
three important observatories, which are to A D
Yerkes, Mt. Wilson, and Palomar. Henrietta Ejnar Hertzsprung was one of the Hertzsprung-Russell
Swan Levitt discovered that a Cepheid, a diagram inventors, which depicts the relationship between
the absolute magnitude of stars and their spectral type. He
type of variable star, could be used as a
also contributed to discovering the distance to the Small
distance marker, allowing her to calculate Magellanic Cloud, a galaxy visible from the southern
astronomical distances between objects. hemisphere of the Earth. Karl Schwarzschild studied the
theory of black holes. The Schwarzschild radius is the
distance from a black hole at which bodies' escape
1877 1957 . .
velocity exceeds the speed of light, rendering them
invisible. Centered on Einstein's Theory of Relativity, he also
to A D wrote extensively on the curvature of space.
Henry Russell, an American astronomer, was the inventor
1879 1955 . .
of the Hertzsprung-Russell diagram, which described the
spectral types of stars. He used photography to calculate
the stars' parallax, enabling them to be positioned to A D
correctly on the H-R diagram.
Albert Einstein proposed his Special Theory of
Relativity, which generalized Newtonian Mechanics
1882 to 1944 . . A D
to very high speeds near the speed of light. It
explains how measurements of physical
phenomena change as observers are moving to
Arthur Eddington proved that Einstein's the phenomenon. Einstein expanded on this in his
calculation of light bending near the General Theory of Relativity, which incorporates
extreme mass of a star is scientifically gravitational effects, in 1915. According to this
accurate. He also notably discovered the theory, the geometry of spacetime is determined
by mass and energy, and curvatures of spacetime
relationship between a star's mass and its
manifest themselves in gravitational forces.
luminosity and indeed studied Cepheid
variables' behavior.
1889 to 1953 A.D.
Edwin Hubble, who from the moment he learned
that distant galaxies are moving away from us,
made a huge contribution to astronomy and
cosmology. The principle, known as Hubble's Law,
states that galaxies recede from each other at a
1900 to 1992 A.D.
rate proportional to their separation. This idea is Jan Oort, a notable Dutch astronomer,
central and vital to the Big Bang theory of the measured the distance between our solar
Universe. system and the center of the Milky Way
Galaxy and calculated the mass of the
1905 to 1997 A.D. Milky Way, firstly. The proposal of many icy
comets left over from the formation of the
George Gamow put forward the idea that solar
solar system, now known as the Oort Cloud,
energy stems from the nuclear fusion process.
is considered an enormous contribution
Gerard Kuiper discovered the Kuiper belt,
which essentially is a large number of comets at that he offered.
the edge of the solar system beyond Pluto's
orbit. He also discovered several moons in the
outer solar system and the atmosphere of
Saturn's moon Titan. Karl Jansky discovered that 1910 to 1995 A.D.
radio waves are emanating from space; this led
Subramanyan Chandrasekhar
to the establishment of the science of radio
astronomy. Clyde Tombaugh discovered the made important contributions to
final planet in our solar system: Pluto. Using the the theory of stellar evolution. He
telescope at the Lowell Observatory in Arizona,
discovered that the Chandrasekhar
he was able to spot the planet using
photography in 1930. limit for white dwarf star stability is
1.4 solar masses: any star greater
1914 to 2006 A.D. than this cannot be stable as a
white dwarf.
james Van Allen discovered the
Earth's magnetosphere. Moreover,
the Van Allen belts are a collection
of radiation belts that cover the
1915 to 2001 . . A D
Fred Hoyle, a firm believer in the Universe's
planet and help to moderate the
steady-state model, therefore dismissed the
amount of solar radiation that Big Bang Theory. However, he was the one
reaches Earth. who invented the phrase "Big Bang." Fred
1923 2010 . .
Hoyle also claimed that comets transport
early life forms and that the Earth's encounter
to A D with a comet is how life first appeared on our
planet. Robert Dicke believed that it was
Edwin Hubble worked at the Mount plausible to detect radiation left over from
Wilson Observatory using a 60-inch the Big Bang. He invented the infamous
reflector telescope to prove that microwave radiometer, which has a
wavelength of one centimeter to detect
galaxies separate systems outside of
radiation.
our own Milky Way and that the
1930 1933 . .
Universe was expanding. Alan
Sandage discovered the first quasar to A D
and calculated the ages of many
Karl Jansky discovered radio
globular clusters.
waves from space. Roger Penrose
is a British mathematician who
1934 to 1996 . . A D
expanded the physics of black
holes by displaying that
Carl Sagan claimed that we are not alone
singularities in space were
in the world; he popularized astronomy
among the general public, revolutionized responsible for their existence.
science fiction, and promoted the quest Arno Penzias co-discoverer of the
for extraterrestrial intelligence. Robert cosmic microwave background
Wilson co-discovered the cosmic radiation, which is considered as
microwave background radiation leftover
radiation left over from the Big
from the Big Bang. Grote Reber built the
first radio telescope and reported the first Bang.
radio telescope survey of the sky. Hans
Bethe explains the energy source of the
Sun and other stars. Alan Guth developed 1942 to 2018 . A D
a new theory called the inflationary Stephen Hawking was an English theoretical
Universe; The theory predicts that the physicist, is another great thinker from the
twentieth century. In order to show that black
Universe is simply flat and infinite.
holes emit radiation and ultimately evaporate,
he merged general relativity and quantum
theory. Despite becoming totally immobile
due to Lou Gehrig's disease, he has written
several books to educate the general public
about astronomy, physics, math, and
cosmology.
1957 to 1963 A.D.
Russian Sputnik 1 satellite became
the first man-made object to orbit
the Earth, marking the beginning of
the space age. Geoffrey Burbidge et 1992 to 1998 A.D.
al. explained how elements form in
Wolszczan and Frail, radio
stars. Maarten Schmidt discovers that
quasars are located at immense
astronomers, announced the
distances from the Milky Way and are discovery of the first definitive
thus brighter than most other objects detection of exoplanets. Reinhard
in the Universe. Genzel and Andrea Ghez find
conclusive evidence for a
supermassive black hole at the
2003 to 2006 A.D center of the Milky Way.
The Hubble Space Telescope
took repeated images of a
region of the sky that, when
combined, makes up the 2015 A.D.
Hubble ultra deep field or the
most profound picture of the The Laser Interferometer
Universe ever made. The Gravitational-Wave Observatory
reports the detection of
International Astronomical
gravitational waves from the
Union demotes Pluto to the new merger of two black holes about
category of 'dwarf planet.' 1.3 billion light-years from Earth.
MEMBERS:
NICOLE LEXI RANOCO
JENNYLYN DE OCAMPO
JOSHUA DELOBRINO
SHAIRA RESTAR
LORENZO PRE
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