Download III. Contents of The Universe

The Universe
How old? 15 billion years old?
I. Definition of the Universe
 All matter that exists now, in the
past and in the future.
 Everything in space and time.
 There is only one universe.
 Anything that exists is part of the
universe.
II. Measuring The Universe
A. Light year (ly)
 Distance light travels in one year
 1 ly = 6 trillion miles (6.0 x 1012)
 Light travels 3.0 x 108m/s or 186,000
mi/s
 Used for distance between stars, galaxies
 Closest star (after the sun) – Alpha
Centauri (aka Proxima Centauri)- 4.3 ly
B. Parallax
 the apparent shift
of an object
against a
background
 due to a change
in observer’s
position
Sun/Stars vs Planet
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Suns are stars
Stars give off energy (light and heat) due to
nuclear fusion, planets do not (NOT ENOUGH
MASS)
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Nuclear fusion is the process of hydrogen fusing to
form Helium and other elements…this process is
the life cycle of stars. When fusion starts, stars are
born, when it stops, stars die.
III. Contents of The Universe
A. Galaxies
 Collection of millions, billions, etc. of stars held
by gravity
 Between stars, interstellar matter (clouds of
dust, gas)
 Andromeda – 2 million ly
 Types of galaxies:
1. Spiral
2. Elliptical
3. Irregular
1. Spiral Galaxies
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arms containing
gas and dust
stars form in arms
young stars are
blue
central bulge
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The Milky Way – spiral galaxy
Our Solar System is in an arm
See video – structure of Milky Way
2. Elliptical
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Spherical or egg shaped
Older galaxies, older
stars
Less gas and dust
3. Irregular Galaxies
No well defined shapes
Vary in age and activity
III. Contents of The Universe
B. Stars – balls of hot gas that emit light
 The Sun is the closest star to us
1. Multiple Star System
 most stars that we see in the sky are parts of
multiple star systems
 revolve around each other.
 two stars = binary star system.
 ex. Algol, eclipsing binary
B. Stars
2. Star Cluster
Group of stars held together by ________.
Open and globular
Pleides, 7 sisters
47 Tucana, second brightest
B. Stars
3. Nova
 a star that spits out some of its material and
becomes brighter in the process
B. Stars
4. Constellations
 Stars create apparent shape in Earth’s sky
called constellation
 Why were they used?
 Season
 Navigation
 entertainment
Naming the Stars
(this slide is just for fun)
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Proper names are often a literal description of the
star’s location in the constellation:
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Betelgeuse – “Shoulder of the giant”
Rigel – “Foot”
Deneb – “Tail”
Procyon – “Before the dog”
Algol – “Eye of the ghoul”
Star proper names also sometimes describe the star.
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Sirius – “Scorching”
Antares – “Rival of Mars”
Kochab – “Star”
Bayer Letter Names
(this slide is just for fun)
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Nearly every star with a proper name also has a Bayer
Letter Name (alpha – brightest star in galaxy, etc.)
You can use the names to make a guess as to how
bright the star is relative to its neighbors in the
constellation:
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Alpha Orionis = Betelgeuse
Beta Orionis = Rigel
Alpha Canis Majoris = Sirius
Alpha Canis Minoris = Procyon
Alpha Geminorum = Castor
Beta Geminorum = Pollux
Alpha Scorpii = Antares
Beta Persei = Algol
III. Contents of The Universe
C. Planets – bodies that do not emit light
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There are eight true planets in our solar system.
There are planets outside our solar system.
There are other solar systems.
III. Contents of The Universe
D. Asteroids, Comets,
Meteors
1. Asteroids – large
space rocks
Eros was visited by the NEAR Shoemaker probe, which
orbited it, taking extensive photographs of its surface, and, on
February 12, 2001, at the end of its mission, landed on the
asteroid's surface using its maneuvering jets.
2. Comets - Small, icy celestial body
is made up of:
 a nucleus (solid, frozen ice, gas
and dust),
 a gaseous coma (water vapor, and
other gases)
 and a long tail (made of dust and
ionized gases).
The tail develops when the comet is
near the Sun.
I. The Universe
3. Meteroid – rock or metal traveling
through space
4. Meteor – meteoroid that enters Earth’s
atmosphere
5. Meteorite - A rock of extra-terrestrial
origin found on Earth.
See video on meteors, then asteroids
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Barrington Crater in Arizona, 0.8 miles
See video, damage Earth Collison, protecting Earth
E. Nebula
 clouds of gas and dust in space
 some are illuminated by nearby stars
(bright nebulae)
 others remain dark and are only seen if
they obscure a brighter object (dark
nebulae)
Witchhead in near Rigel, Orion
Trifid nebula
Planetary nebula
F. Quasar
 Most distant object in universe
 "quasar'' means "quasi-star''
 produce more light each second than an
entire galaxy of stars does
G. Dead Star Remnants
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Black holes
Neutron stars
White dwarf
IV. Creation of The Universe
A. Big Bang Theory
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Theory: started as a small, dense mass that
exploded, matter sent in all directions, forming
the universe
Can never be proven.
See video –big bang
IV. Creation of The Universe
(do not copy)
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Singularity – point when all
matter contained in small point.
Explosion – created space,
time, matter, and four
fundamental forces
Forces: strong nuclear, weak
nuclear, gravity and
electrostatic
IV. Creation of The Universe
B.
Support
1. The Doppler Effect, Red Shift
 Doppler Effect - when motion changes a wave's perceived
frequency
 Starlight shifts to red and of rainbow spectrum
 Supports the big bang theory (universe is expanding)
Galaxies move away
From us…shift to
red
You are
Here
2. Cosmic Background Radiation – microwave radiation
detected throughout the Universe
C. Future: The Universe will….
1.
2.
3.
Continue to (open universe)
Stop expanding and hang out (closed universe)
Begin to collapse and ‘reexplode’ (the big crunch)