Transcript combined astro show 2013x

Electromagnetic Waves with Wavelengths
1 nm = 1 x 10-9 meters
What can LIGHT tell us about the objects in
space that produce them?
The composition of the gas, by comparing to known gases in the lab
The temperature of the gas, generally the spectral lines of various elements become
more prominent at certain temperatures
The motion of the object producing the lines, either towards us or away
from us. This is known as the Doppler Effect
There are 3 types of light spectrums that we
see in space:
(Bright line)
#1) A continuous spectrum
(Dark line)
is produced by a HOT glowing solid
#2) A bright line spectrum or emission spectrum
is produced when a low density gas (like in a nebula)
is HOT and glows
(Bright line)
(Dark line)
Each element has its own characteristic bright line spectrum
Emission Spectrum (Bright-line)
#3) An absorption spectrum or dark line spectrum
is produced when a gas (in space)
comes between the observer and the source of light
(Bright line)
(Dark line)
The Doppler Effect in sound waves
Galaxy is moving
away from us
Normal line
position
So is this galaxy moving towards
or away from us?
Would this be a blue shift or red shift?
So is this galaxy moving towards
or away from us?
Would this be a red shift or blue shift?
These galaxies all show high
red shifts
Farthest look yet into space
Why are all galaxies Red Shifted?
• Universe began with the
Big Bang about 13-14
billion years ago
• The universe is
expanding!
• Cosmic Background
Radiation is the “echo” of
the Big Bang
• Will the Universe expand
forever or collapse in a
Big Crunch?
• Oscillating Universe?
• The expansion of the
Universe is speeding up!
• Dark Energy?
• Dark Matter?
• Big Freeze?
All stars are contained in galaxies
Our own Milky
Way galaxy
contains around
200 billion suns
This is what our own galaxy
(the Milky Way) might look
like if we could get far enough
outside of it and view it face on
Top view of what Milky Way would look like
Spiral Galaxy
(viewed face on)
Spiral Galaxy
(viewed edge-on)
Elliptical Galaxies – these
galaxies have no spiral arms
Irregular Galaxies
Stable
main sequence
star
Fusion
Hydrogen + Hydrogen
makes
Helium + energy
Fusion is what makes all stars SHINE
Luminosity
….Means how BRIGHT a star APPEARS
• BIG stars appear brighter
• CLOSE stars appear brighter
• HOT stars appear BLUE
Betelgeuse in Orion is a Supergiant (red)
Rigel is BLUE
Medium size
Large Size
Know this sequence of events
in the lives of stars!
H-R Diagram
• Most stars spend most of their lives on the
MAIN SEQUENCE
• Dying Stars: Red Giants and Super Giants
• Dead Stars: White Dwarfs, Black Dwarfs,
Neutron Stars, Black Holes
Dying stars
Young &
Middle aged stars
Dead stars
Milky Way: Our Galaxy
Pointer Stars point to Polaris
Polaris and Circumpolar stars
Cassiopeia the Queen
Cepheus
the
King
Orion the Hunter
Left shoulder star
is Betelgeuse, red giant,
12th brightest star
Right knee star
is Rigel
(blue-white),
7th brightest star
Sagittarius (“teapot”)
Where am I?
In….Red Hook High School
In…Red Hook Village
In….Upstate NY
In…..Eastern North America
On…. Planet Earth
In…. The Solar System
Nearest Star to the Sun
In…. The Solar Neighborhood
In… The Milky Way Galaxy
Nearest Neighbor Galaxy
In… The Local Group of Galaxies
In… The Local Supercluster of Galaxies
Nearest Neighbor Superclusters
In the Universe