Transcript Universe ppt - Killeen ISD

Galaxies on a Collision Course in the Hubble Ultra Deep Field Image
http://hubblesite.org/gallery/album/the_universe_collection/pr2004007d/

Stars, (including our sun) are spheres of hot,
glowing gas.

Stars give off 2 types of electromagnetic
radiation:
 visible light
 radio waves
Electromagnetic Radiation
(Wave)- is a transverse wave
that does not need a medium to
travel through; therefore it is
able to travel through space.
Short
wavelengths
Long
wavelengths
R.O.Y.G.B.I.V
All these waves can travel through space because they do not need a medium.
Wavelength
(metres)
long
short
low
Frequency
high
R
(Hz)
O
Y
G
B
I
V

Spectrograph – breaks the light from an object into
colors and photographs the resulting spectrum; this
allows astronomers to identify the chemical
composition and temperature of a star; each
element has a unique set of lines on a spectrum

Astronomers infer how hot a star is by comparing
its spectrum with the known spectra of elements at
different temperatures. Stars at different
temperatures produce different spectra.

Universe is defined as all of space and
everything in it

Galaxy is a cluster of stars, gases, and dust
held together by gravity
 We are part of the
 Milky Way Galaxy;
nearest galaxy is
Andromeda Galaxy
Spiral Galaxy NGC 3949
http://hubblesite.org/gallery/album/the_universe_collection/pr1994002c/
Proxima Centauri is the nearest star (with the exception of our sun), it is 4.5 light-years away

Distances to stars are
SO large they are
measured in lightyears
 the distance light travels
in one year at a speed of
300,00 km per second or
 9.5 million million km;

light-year is a unit of
distance, NOT time!
http://www.daviddarling.info/images/
Proxima_Centauri.jpg
Proxima Centauri is
the nearest star (with
the exception of our
sun), it is 4.5 lightyears away
 1. Size
 2. Color and Temperature
 3. Brightness

SIZE: in order from smallest to largest
 Neutron Star
smallest
 White Dwarf
 Medium size stars (our Sun)
 Red Giants
 Super Giants
largest
http://hubblesite.org/gallery/album/nebula_collection/
Light Echoes From Red Supergiant
Star V838 Monocerotis – September
2002
Our Sun is a medium size star- here it is
compared to the planets in our solar
system
Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C)
and Rigel is the blue-white star in his heel (over 15,000 oC)

– a star’s color reveals
its temperature!
Red is the coolest
Blue is the hottest

Ex. in the constellation Orion the Hunter,
Betelgeuse is the red star in his shoulder (5,
500 o C) and Rigel is the blue-white star in
his heel (over 15,000 oC)
Ex. in the constellation Orion the Hunter, Betelgeuse is the red star in his shoulder (5, 500 o C)
and Rigel is the blue-white star in his heel (over 15,000 oC)
AKA: brightness or luminosity or magnitude
 The brightness of a star depends on its size
and temperature

How bright a star looks from Earth depends
on:
 1. how far the star is from Earth AND
 2. how bright the star actually is (absolute
magnitude)
http://stloe.most.go.th/html/lo_index/LOcanada9/907/1_en.htm
ABSOLUTE MAGNITUDE – THE
BRIGHTNESS THE STAR WOULD
HAVE IF IT WERE A STANDARD
DISTANCE FROM EARTH
APPARENT MAGNITUDE – THE
STAR’S BRIGHTNESS AS SEEN
FROM EARTH; HOW BRIGHT THE
STAR “APPEARS” TO BE
 Stars don’t last forever.
Each star is
born, goes through its life cycle, and
eventually dies. Astronomers study
many stars and see how they differ
from each other.
•a nebula is a large amount of gas and dust spread out in an immense volume
Gravity begins to pull some of the gas and dust in the nebula together to form a ‘protostar’
Crab Nebula
1. A large amount of gas and dust spread out in an
immense volume in the nebula
2. In the nebula gravity begins to pull some of the gas
and dust together and it becomes more and more dense.
3. The contracting gas and dust become so hot that
nuclear fusion starts and enormous amounts of energy
are released;
4. this is the earliest stage in a star’s life; a protostar
Horsehead Nebula
http://hubblesite.org/gallery/album/nebula_collection/
A Perfect Storm of Turbulent
Gases in the Omega/Swan
Nebula
The Cat's Eye Nebula: Dying
Star Creates Fantasy-like
Sculpture of Gas and Dust
Gas Pillars in the Eagle Nebula: Pillars of
Creation in a Star-Forming Region
The Spirograph Nebula
The Cone Nebula
Veil Nebula

How long a star lives depends on how much mass
it has. Stars with less mass last longer than stars
with more mass!

Small stars use up their fuel more slowly than large stars so
they have much longer lives!

Small mass = long life

Medium-sized stars like the sun can live for up to 10
billion years- (astronomers think the sun is about 4.6 billion years
large mass = short life
old so it is almost halfway through its lifetime)
White Dwarf-the remaining blue-white
hot core of a red giant after the outer
part has drifted away
*about the size of
Earth with the
mass of the sun
*have no fuel but
glow faintly from
leftover
Ancient, White Dwarf Stars in
the Milky Way Galaxy
White Dwarf, the final
stage of a dying star, the
bright white center is the
star and the colors around
is the gasses being
expelled from the center
Black Dwarf:
These are
what remain
of a dead
white dwarf
star after the
heat has
radiated into
space.
www.moonpebble.us/Images/BlackDwarf.jpg
http://hubblesite.org/gallery/album/nebula_collection/
Supersonic Shock Wave Heats Gas Ring
Around Supernova 1987A
S
U
P
E
R
N
O
V
A
Details of Supernova
Remnant Cassiopeia A
Gaseous Ring Around
Supernova 1987A
An explosion of a giant or
supergiant
some material expands into
space and can become part
of a nebula to form a
‘recycled star’
a tinya star
tiny star
that that
remains
remains
afterafter
a supernova;
a supernova;
science.nationalgeographic.com/staticfiles/NG...
Neutron Star
A tiny star that remains after a
supernova
An artist's rendering shows a neutron star—located 50,000 light-years from Earth—that flared
up so brightly in December 2004 that it temporarily blinded all the x-ray satellites in space and lit
up the Earth's upper atmosphere. The flare-up occurred when the star's massive, twisting
magnetic field ripped open its crust, releasing an explosion of gamma rays.
http://hubblesite.org/gallery/album/search.php?method=and&format=normal&sort=score&config=picturealbum&restrict=entire_collection%
2Fpr&exclude=&words=black+hole&Submit=Search+site&page=2
Black Hole-Powered Spiral Galaxy
NGC 7742
Dust Disk Surrounds a Massive Black Hole in Elliptical
Galaxy
BLACKHOLES: the remains of a massive star pulled into a small volume
by gravity;
these are the most massive stars, 40x more massive than the sun; force/pull of gravity is so strong that
nothing can escape, not even light

graph used by astronomers; also called
the H-R Diagram shows the relationship
between the surface temperature and
the brightness(magnitude/luminosity)
of stars
Here × marks the sun
Hertzsprung-Russell
Diagram:
main sequence
Most of the points
form a diagonal
band called the
main sequence
(this includes more
than 90% of all
stars) surface
temperature
increases as
brightness
increases

http://sunshine.chpc.utah.edu/labs/star_life/s
upport/HR_init.swf

http://sunshine.chpc.utah.edu/labs/star_life/s
upport/HR_animated.swf

http://sunshine.chpc.utah.edu/labs/star_life/s
upport/HR_static.swf
Quasar:
http://hubblesite.org/gallery/album/entire_collection/pr2003015c/
A distant
galaxy
with a
black
hole at its
center
Andromeda Galaxy
Our closest neighboring galaxy
Hubble's Sweeping View of the Coma Cluster of
Galaxies
http://hubblesite.org/gallery/album/galaxy_collection/pr2008024a/
Types of Galaxies
Type
Description of Shape
Spiral Galaxy Arms that spiral outward, like
pinwheels
Elliptical
Looks like flattened balls;
Example
Milky Way
there is little gas and dust between the
stars; most contain only old stars
Irregular
Does not have a regular shape;
Smaller than spiral and elliptical
The Large
Magellanic
Cloud
http://hubblesite.org/gallery/album/galaxy_collection/+1
Barred Spiral
Galaxy NGC
1300
The Tadpole Galaxy:
Distorted Victim of
Cosmic Collision
Spiral Galaxy M100
Grand Design Spiral
Galaxy M81
Whirlpool Galaxy and Companion Galaxy
http://hubblesite.org/gallery/album/galaxy_collection/+1
Spiral Galaxy NGC 3949: A Galaxy Similar to the Milky Way
science.nationalgeographic.com
Galaxy Centaurs A
NGC 1316, a giant elliptical galaxy formed billions
of years ago when two spiral galaxies merged
: www.britannica.com
Cigar Galaxy
NGC1427A
Sagittarius Dwarf Irregular Galaxy

Moving Galaxies - Astronomers use information
about how galaxies are moving as one way to develop ideas
about how the universe formed. By examining the visible
light spectrum of a galaxy, astronomers can tell how fast the
galaxy is moving toward or away from our galaxy (the Milky
Way). Only a few of the nearby galaxies are moving toward
us, most are moving away.

Edwin Hubble, an American astronomer discovered that the
farther away a galaxy is from us the faster it is moving away
from us. The Hubble Space Telescope was named in his
honor.

Origin of the Universe –
Big Bang Theory states that the universe
began with an enormous explosion about 10 to 15
billion years ago. Since that explosion the universe
has continued to expand.
(p. 302, Fig. 20 and Fig. 21 on p. 303)

About 5 billion years ago, a cloud of gas and dust (nebula) collapsed to
form our solar system