THE SUN, EARTH, AND MOON
• Astronomy: study of the space and the
universe.
EARLY
ASTRONOMY
• Includes all celestial bodies and phenomena.
• Greeks made huge contributions to what we
know of astronomy today
• Came to conclusions about the cosmos
using philosophical arguments and
observational data
HIPPARCHUS
• Pre-Ptolemy
• 190-120 BC
• Mathematician
• Measured the distance between the
Earth and the moon using basic
trigonometry
• Invented the Astrolabe
ASTROLABE
ARISTOTLE
• 384-322 BC
• Philosopher and polymath
• Polymath: wide range of knowledge (think da Vinci)
• Used the curved shadow of Earth on the
moon during the eclipse to assume that the
Earth was round.
• His belief was abandoned in the Middle Ages
ERASTOSTHENES
276-194 B.C.
• Mathematician
• First successful attempt to establish the
size of Earth.
• Calculated circumference of the Earth
using the Post of Alexandria and the
Well at Syene.
•
C A L C U L AT I N G
E A RT H ’ S
CIRCUMFERENCE
GEOCENTRIC VS
HELIOCENTRIC
• Geocentric Model
• • In the ancient Greeks’
geocentric model, the moon,
sun, and the known planets—
Mercury, Venus, Mars, and
Jupiter—orbit Earth.
• Heliocentric Model
• In the heliocentric model,
Earth and the other planets
orbit the sun
CLAUDIUS PTOLEMY
• 100-170 AD
• Mathematician, astronomer, philosopher, geographer, and
astrologer.
• Believed in the Geocentric model.
• Was proven incorrect by Galileo.
• So why do we still learn about him?
• Think back to scientific inquiry. Incorrect answers are just as
important as correct answers. Incorrect answer narrow what we
perceive as truth.
ARISTARCHUS
• 312-230 B.C.
• Mathematician and astronomer
• First Greek to believe in a sun-centered universe (heliocentric)
• Attempted to calculate the distance between the Earth, Sun,
and moon.
• Though evidence supported it for 1500 years the Geocentric
model dominated Western thought.
Ptolemy created a model of the
universe that accounted for the
movement of the planets.
Retrograde motion is the
apparent westward motion of
the planets with respect to the
stars.
PTOLOMAIC
SYSTEM
RETROGRADE
MOTION
• 1473-1543
NICOLAUS COPERNICUS
• Polish mathematician and
astronomer.
• Copernicus concluded that
Earth is a planet. He proposed a
model of the solar system with
the sun at the center.
TYCHO BRAHE
• 1546-1601
• Danish nobleman, astronomer,
and writer.
• Lost his nose in a sword fight
and wore a “prosthetic” made
of copper.
• Invented devices that measured
the locations of celestial bodies.
• More precise observations than
anyone else previously.
• This especially goes for the
position of Mars.
• 1571-1630
• German
astronomer
• Played a key part in
the 17th century
scientific revolution.
• Created what we
know as “law of
planetary motion”.
JOHANNES KEPLER
KEPLER’S LAWS
1. Orbits of the planets are
elliptical.
2. Planets revolve around the
sun at varying speed.
3. There is a proportional
relationship between a
planet’s orbital period and its
distance to the sun.
• Ellipse- oval-shaped path
• AU- the average distance between the
earth and the sun (150 million km)
PLANET
REVOLUTION
GALILEO GALILEI
• 1564-1642
• Italian polymath
• Known as the father of:
• Observational astronomy
• Modern physics
• Scientific method
• Most important contributions were his
descriptions of the behavior of moving
objects.
• Developed his own telescope and
discovered a plethora of important
discoveries:
1.
Four satellites (moons) orbiting Jupiter
2.
Planets are circular disks and not just bright
points
3.
Venus has phases just like the moon
4.
The moon’s surface is extremely bumpy
5.
There are spots (dark regions) on the sun’s
surface
GALILEO (CONT.)
SIR ISAAC
NEWTON
• No, an apple did not fall on his
head.
• 1643-1727
• English mathematician, physicist,
astronomer, theologian, and
author.
• Recorded by William Stukely and
archived by the Royal Society:
• “Why must apples always
descend perpendicularly to the
ground?”
UNIVERSAL
GRAVITATION
• Gravity: the force of
attraction that exists
between any two
masses.
• Force decreases with
distance.
• Greater the mass,
greater the force.
STONEHENGE
MOTIONS OF EARTH
• Rotation: turning, or spinning, of a body
on its axis.
• Mean solar day
• The time interval from one noon to the
next (approx. 24 hrs).
• Sidereal day
• The time it takes for Earth to complete
360 degrees (approx. 23hr, 56 min, 4 sec)
• Revolution: motion of a celestial body
along a path around some point in space.
• Perihelion
• The time in January when Erath is
closest to the sun.
• Aphelion
• The time in July when Earth is farthest
from the sun.
ROTATION VS REVOLUTION
MOTIONS OF
EARTH
• Axis and the Seasons
• The plane of the
ecliptic is an imaginary
plane
• Connects earth’s
orbit with the
celestial sphere
• The tilt in the axis leads
to the yearly cycle of
seasons.
MOTIONS OF
THE EARTH
• Precession- traces out a cone
over a period of 26,000 years
• The solar system moves in the
direction of the star Vega
• The sun revolves around the
galaxy
• Earth is slowly approaching
Andromeda, our galaxy
neighbor
APOGEE AND PERIGEE
THE POINT AT WHICH THE MOON THE POINT AT WHICH THE MOON
IS FARTHEST FROM EARTH.
IS CLOSEST TO EARTH.
LEONARDO DA VINCI
• 1452-1519
• Italian polymath
• Made the determination that the phases
of the moon came from the light from
the sun reflecting on earth’s surface.
• Published in the Codex Leicester in 1510.
• One of the most famous polymaths in
history.
PHASES OF THE
MOON
• Progression of changes
in the moon’s
appearance (monthly
cycle)
• Result of light from the
sun reflected om
earth’s surface and the
motion of the moon.
LUNAR MOTIONS
• Synodic month: 29. 5 days.
• Based on the moon’s phases.
• Sidereal month: 27.33 days.
• True period of the moon’s revolution around the earth.
• The different of the two days is due to the Earth-moon system orbiting the
Sun.
• The period of rotation of the moon is the same as Earth. This causes the same
lunar hemisphere to always face Earth.
LUNAR
MOTIONS
TYPES OF
ECLIPSES
• Solar eclipses
• Occur when the
moon moves in a line
directly between the
Earth and the sun
• Casts a shadow on
Earth
TYPES OF
ECLIPSES
• Lunar Eclipses
• Occurs when the moon
passes. through the Earth’s
shadow
• During a new-moon or
full-moon phase, the
moon’s orbit must cross
the plane of the ecliptic
for an eclipse to take
place
THE LUNAR SURFACE
• Craters
• A depression at the summit of volcano or where a meteorite impacted
• Most craters were produced by the impact of rapidly moving debris
• Rays
• any of a system of bright, elongated streaks, sometimes associated with a crater on
the moon.
• Highlands
• Densely-pitted, light-colored areas
THE LUNAR SURFACE
• Maria
• Ancient beds of basalt that were formed when impacts allowed magma to bleed
through the surface
• A rille is a long channel associated with maria that are similar to a valley or trench.
• Regolith
• thin, layer consisting of loosely compacted, fragmented material believed to have
been formed by repeated meteorite impacts
THE MOON’S SURFACE
Mare Imbrium
(Sea of Rains)
Kepler
Crater
Copernicus
Crater
Mare Tranquillitatus
(Sea of Tranquility)
TOPOGROPHY
LUNAR HISTORY
• The most widely accepted model for the origin of the moon is that
when the solar system was forming, a body the size of Mars impacted
Earth. The resulting debris was ejected into space, began orbiting
around Earth, and eventually united to form the moon.
MOON LANDING
• The race to space was a
monumental period of
events that forever
changed our relationship
with the cosmos.
• One of those events was
known as the Apollo 11
mission that made Neil
Armstrong and Buzz
Aldrin the first ever
humans on the moon.
KATHERINE JOHNSON
• In 1969, Neil Armstrong became the first
man to walk on the moon. However…
• …he would not have gotten there had it
not been for Katherine Johnson and her
precise mathematical calculations of the
orbital trajectory for the Apollo 11
mission.
• Lead to the movie Hidden Figures, in
which she was played by Taraji P. Henson.
• 1918-2020
• Born in West Virginia
• Graduated from West Virginia State
College.
KATHERINE
JOHNSON
MARY JACKSON
• 1921-2005
• Hampton,VA
• Hampton Institute in
Mathematics and Physical Science
• Engineer
• Staunch advocate for the rights
of women and minority groups in
the STEM fields.
• Extracted data from wind tunnel
and flight tests.
• Born in 1942 in Monroe, NC
• The George Washington University
• Aeronautical Engineer
• Wrote the computer program for a sonic
boom that led to sonic boom minimization
studies for 25 years.
CHRISTINE DARDEN
DOROT H Y
VAUG H AN
• Key figure in the desegregation
of STEM fields.
• 1910-2008
• Kansas City, MO
• Mathematician
• Math teacher in Farmville, VA
during WWII.
• First African American
supervisor hired by NASA,
monitoring the “West Area
Computing” unit.