Transcript 1.2.3 full astronomy pptx

Astronomy
Earth’s Place
in the Universe
Warm Up
1.What do you think of when
you hear astronomy?
2.What are you the most
curious about in astronomy?
3.What do you know about
astronomy?
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https://www.youtube.com/watch?v=D
8zZZZzppIM
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What is Astronomy?
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The science that studies
the universe that deals
with
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Properties of objects in
space
Laws under which the
universe operates
Universe is made of galaxies which are made of many
stars. Some stars have planetary systems similar to
our solar system. Earth is a satellite planet of one
particular star
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Hierarchy of the Universe
Universe- everything that exists
Galaxies- contain stars, other remnants, and
sometimes planetary systems
Star- A star is a luminous sphere of plasma held
together by its own gravity. The nearest star to Earth
is the Sun
Planet- an astronomical object orbiting a star or stellar remnant
that
● is massive enough to be rounded by its own gravity,
● is not massive enough to cause thermonuclear fusion, and
● has cleared its neighbouring region of planetesimals.
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Famous Astronomers
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The Ancient Greeks
Ptolemy
Copernicus
Brahe
Kepler
Galileo
Newton
Famous Astronomers
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Ancient Greeks
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Ptolemy: 141 AD
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Geocentric view (Earth centered)
7 heavenly bodies (Sun, Moon, Mercury – Saturn)
and stars
Aristachus – Heliocentric (Sun centered),
retrograde motion
Geocentric Model
Copernicus: 1473 – 1543
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Earth was a planet
Model of the Solar System – Sun centered heliocentric
Famous Astronomers
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Brahe: 1546 – 1601
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Solar Eclipses
Stellar paralax – shift in
star’s position
Geocentric universe
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■Galileo:
1564 – 1642
■Telescope in 1609
■4 moons of Jupiter
■Sunspots
Newton: 1643 – 1727
Law of Universal Gravitation (Gravity)
3 Laws of Motion (Inertia, forces, action/reaction)
Supported Kepler
Father of calculus
https://www.youtube.com/watch?v=4p3Np6eivZ8
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Famous Astronomers
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Kepler: 1571 – 1630
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3 Laws
✓ 1st law: The orbits of the
planets are ellipses, with the Sun
at one focus of the ellipse.
✓ 2nd law: The line joining the
planet to the Sun sweeps out
equal areas in equal times as the
planet travels around the ellipse.
✓ 3rd law: The ratio of the
squares of the revolutionary
periods for two planets is equal
to the ratio of the cubes of their
semimajor axes.
Warm Up
1.In your own words
summarize the three laws
of Kepler.
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Objective
■By the end of class, you
should:
■Discuss the theories of the
beginning of the universe.
■Be able to distinguish the
different types of galaxies.
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■ Big BangHof
theory
History
the Universe
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States that at one time, the
entire universe was confined
to a dense, hot, super-mass
ball
About 13.7 billion years ago,
a violent explosion occurred,
hurling this material in all
directions
Marks the beginning of the
universe
https://www.youtube.com/wa
tch?v=uabNtlLfYyU
Nebula Theory
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Theory of how the bodies of our solar
system evolved from an enormous
rotating cloud called the solar nebula.
Made up of Hydrogen and Helium
Theory how the planets were formed
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The Expanding Universe Theory
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The Expanding Universe Theory,
developed from the observed red
shifts of celestial bodies, that the
space between galaxies is
expanding, so that they appear to
recede from us at velocities that
increase with their distance
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Types of Galaxies
Spiral
■ Disk-shaped with concentration of
stars in the center and
“arms”extending from the center
■ Contain old and young stars
■ Ex) Milky Way Galaxy
■ Elliptical
■ Round to oval in shape
■ Contain old stars
■ Ex) giant diffuse galaxies -largest
■ Irregular
■ No definite shape
■ Composed of young stars
■ Ex) Large and Small Magellanic
Clouds (closest neighbor galaxies)
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Agree or Disagree?
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___ Kepler discovered that the path of
each planet around the sun is an
ellipse.
___ The universe is made of galaxies,
galaxies contain stars, stars may have
planetary systems.
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Agree or Disagree?
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Electromagnetic radiation includes gamma
rays, X-rays, ultraviolet light, visible light,
infrared radiation, microwaves and radio
waves.
Nuclear fission and fusion are the same
thing.
Sunlight is used in the process of
photosynthesis for plants and other
autotrophs to make energy.
Any living thing could exist without sunlight.
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The Sun
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Solar Interior or Core
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The Sun produces
energy by a process
known as nuclear
fusion
Convection currents
occur here
Enough fuel to last
another 5 billion years
Fusion and Fission
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Fusion
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Particles “Fuse” together to create energy
Found on the Sun and Stars
Fission
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Particles split to create energy
Found in Nuclear Reactors splitting atoms
to create energy
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Energy from the Sun
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Solar energy into chemical energy
through photosynthesis
Plants use sunlight to produce sugar
through the actions of the chlorophyll
Chemical Formula
■ 6H2O
+ 6CO2 ----> C6H12O6+ 6O2
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How does the magnetic
field protect us from
harmful solar radiation
rays?
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Agree or Disagree
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Revolution is the motion of a body along a
path around some point in space.
Rotation is the turning, or spinning, of a
body on its axis.
Barycenter is the center of mass between
celestial objects.
Nutation is the wobble movement observed
in precession.
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Agree or Disagree
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Precession is a slow movement in rotation of
a body on its axis.
Earth’s revolution results in day and night.
One Earth around rotation the sun is a year.
Seasons on Earth are due to the Earth’s
rotation around the Sun.
Seasons of the Northern and Southern
hemisphere are opposite.
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Light
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Electromagnetic radiation (spectrum)
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Gamma rays - fastest
X-rays
UV rays
Visible spectrum (ROYGBIV)
Infrared waves
Radio waves – slowest
Electromagnetic Spectrum: The arrangement
of these waves according to their wavelengths
and frequencies
Light: Wave or Particle?
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Wave: Found on
Earth
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Particle: Photons
found in space
Spectroscopy
Study of the
properties of light
that depend on
wavelength.
■ Visible white light
passes through a
prism producing the
colors of the
rainbow (ROYGBIV)
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Rotation
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The turning or spinning of
a body on its axis
Causes day and night
Two kinds of measurement
■ Mean Solar Day – time
interval from one noon to
the next (24 hours)
■ Sidereal Day – time it
takes for Earth to make one
complete rotation (360’)
with respect to a star other
than the sun (23 hours, 56
minutes, 4 seconds)
Revolution
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Motion of a body along a path
around some point in space.
Earth’s orbit is elliptical
Earth’s distance from the sun
varies
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Perihelion
– Earth is closest to the sun
– 147 million km away
– Occurs on January 3rd
Aphelion
– Earth is farthest from the sun
– 152 million km away
– Occurs on July 4th
Precession
■ slight movement,
over a period of
26,000 years where
Earth’s axis points in
different directions
■ Points to two stars
https://www.youtube.com/w
atch?v=0qHjtp4cdC
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Polaris
Vega
Currently pointing to
Polaris
Doesn’t affect the
seasons
Nutation and Barycenter
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Nutation
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oscillatory movement of the
axis of a rotating body or a
wobble
occurs about 18.6 years
Barycenter
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the point between two objects
where they balance each other
the center of mass where two or
more celestial bodies orbit each
other
Barycenter website with
animation
https://www.youtube.com/watch?
v=_IHXj8k2jqc
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Seasons are caused
by the tilting of the
earth on its axis
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When the Earth is
tilted towards the Sun
– warmer seasons
When the Earth is
tilted away from the
Sun – cooler
seasons
How would you describe the
Earth’s shape and
appearance? What affects
its shape?
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Agree or Disagree
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Tides are only caused by the Sun’s
magnetic pull.
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● What are Tides?
● changes in elevation
of the ocean surface
● What causes Tides?
● Gravitational forces
of the moon and sun
Tidal
Range
● Vertical distance
between the high
and low tides.
● Vary from place to
place and week to
week.
Spring
Tides
● Spring Tides
● Occur during the
new and full moons
● All gravitational
forces are added
together
● Extreme high and
low tides
● High tidal range
Neap
Tides
● Neap Tides
● During the 1st and
3rd quarters of the
Moon
● Gravitational forces
are offset
● Tidal range is the
smallest value
Tides
●Tides occur 50
minutes later due
to …
● Rotation pattern of
earth and moon.
● This is known as a
lunar day
Tidal Patterns
● Diurnal (daily)
● one high and one low tide each
lunar day. Occurs at Pensacola,
Fl. And the Gulf coast.
● Semidiurnal (semi-daily)
● 2 high and 2 low tides: each high
and low tides are similar to the
preceding high and low. Occurs
in the Atlantic coast
● Mixed
● 2 high and 2 low tides each day.
Each high and low tides are
different from each other.
Occurs on the west coast.