The Universe
http://www.cartoonstock.com/newscartoons/cartoonists/sni/lowres/snin34l.jpg
The universe is all the matter, ________, and space everywhere.
Why Do Stars Shine?
A star is a large ball of _________ held together by gravity.The gravity is pulling the gasses together, and this forces a ________ reaction to occur.
Nuclear ___________
H + H = He + ________ and heat
the missing mass is turned into energy
E=mc2
What information can star light tell us?
A. Compostion
Spectroscopes- telescopes with ___________ that break down star light into patterns of colors. Each element has its own specific "_____________" of color.
- Bright Line- a few thin bands of ________ against a ________ background (each has its own distinct pattern). One single element is glowing.
- Continuous spectra- a ___________ of smeared colors. Many elements are glowing so bright lines are ___________ together.
- Absorption spectra- a rainbow of colors with a few __________ lines. Gas surrounding a star ABSORBS colors of light indicating the elements present.
Spectra Lab
B. Temperature
Blackbody furnance experiments in making steel showed as the furnace heated up its walls glowed different temperatures depending on the heat.
- Hot temperatures emit ________ colors at 25,000 degrees.
- "Cool" temperatures are ______ in color at 3,000 degrees. .
The hotter the temperature, the shorter the wavelength. Therefore, we can tell the temperature of a star just by observing its _________!
- The order of star temperatures from cool to hot: red-orange-yellow-white-blue
C. Distance, Mass and Brightness
A light year is ____ trillion miles which is the distance that light can travel in a _______.
- Distances between stars are so great that we need to resort to light years to discuss them.
- The closest star is Proxima Centauri, 4.2 light years away. Scale of distance to closest star
A way we can estimate the distance of a star is by using parallax- the closer a star is to us, the greater the background stars will appear to __________ as we orbit the sun.
Apparent Magnitude- how bright a star appears in the sky. But closer dimmer star may appear ___________.
Absolute Magnitude- how bright the star WOULD appear if they were all the same _________.
- Measured at 32.6 light years away.
The luminosity (____________) of a star is roughtly dependent on the stars ______. The brighter stars are larger.
Hertzsprung-Russell H-R Diagram
Stars were graphed based on their temperature and absolute magnitude. Something very odd was discovered.
- _________% of the stars are on the main sequence.
- 80% of the main sequence stars are ______ dwarfs.
H-R Diagram Lab
Stellar Evolution
http://www.astro.psu.edu/users/niel/astro1/slideshows/class15/003-crab-chandra.jpg
Stars evolve too!
Small Mass Stars
- Nebula- Protostar- Main Sequence Star- Red Giant- Plantary Nebula- White Dwarf
When our sun runs out of hydrogen it will turn into a ________ Giant and expand all the way into the orbit of Mars swallowing the _______. Some day your atoms will be part of the SUN! How much time do we have left? _____ billion years!
Large Mass Stars
- Nebula- Protostar- Main Sequence- Red Super Giant- Super Nova- Black Hole OR Neutron Star
- The constellation ORION has a super red giant and a blue giant!
- Black holes are invisible but we can see their ____________ effect on surrounding stars.
- Also gas from surrounding stars can be observed being _________ into the black hole. As it spirals inward it heats up and emits large amounts of X-ray radiation.
Black holes- so dense they capture their own light.
Einstein (1879-1955)
- The _________ you move, the slower time passes. Twin paradox!
- General Theory of Relativity- space-time and light are curved by ____________. Matter deflects light itself!!!! One test of this theory was provided during a solar eclipse. Stars behind the sun were visible!!! This explains why a black hole captures its own light!
How Old is the Universe?
The universe formed 13-14 ________ years ago.
The universe began with the "Big _______."
- A hot tiny sphere of _________ exploded in an incredible burst and began moving outwards.
- The first 700,000 years were _______- energy had to cool down enough to convert into matter.
- The universe is still __________ outwards
How do we know that the universe is expanding? (Proof of the big bang)
- Background Radiation: The remaining __________ of the Big bang is faint and cool and found EVERYWHERE in the sky.
- It is now in the microwave energy sector and roughly 2.7 degrees Kelvin
- Red Shift: Light from the _________ around us appears to stretch and turn red as they race away from us.
- Red light has a ________ wavelength then blue light. Because all the stars are moving away from us (except those in our Milky Way galaxy) their light appears to have lengthened into longer wavelengths and turned ______.
- Blue visible light has a much ________ wavelength than red visible light. If an object is moving toward you, the electromagnetic energy that the object gives off will crowd together. This is called the Blue shift, because the wavelength __________.
http://www.phschool.com/atschool/science_activity_library/images/properties_sound_doppler.jpg
- We can determine how fast a galaxy
is moving toward or away from earth by analyzing the degree of red or blue shift.
- All galaxies are moving away from us, except for the Andromeda galaxy which exhibits a __________ shift.
- Galactic Collisions
- Hubble's Law- the farther a galaxy is away from us, the __________ it is moving, the greater the red shift.
Power of 10- Travel off the Earth's surface from St. Mark's square in Venice! What is most of space filled with?
Four Types of Galaxies
1. Spiral- 30% of the galaxies
- older stars are in the __________ and younger stars are on the arms
- A barred-spiral galaxy is a common type of spiral galaxy
2. Elliptical- 60% of the galaxies
- mostly older stars
3. Irregular- 10% of the galaxies
- mostly blue giants
What galaxy are we in?
The __________ Way, a barred-spiral galaxy.
- It contains 200 -400 billion stars
- It measures 100,000 by 30,000 light years.
- The center of our galaxy is a _________ hole
Galaxy Lab
Local Group
- Like stars, galaxies evolve and group themselves into clusters.
- Our Milky Way and other near by galaxies form a Local Group of 35 galaxies.
- Within a sector of the sky, about the size of a grain of rice, high resolution photos taken for several WEEKS by the hubble telescope reveal ______________ of galaxies.
http://www.californiaindianeducation.org/science_lab/pics/space_photos/Space_Deep.jpg
The Composition of the Universe:
The Search for Dark Energy and Dark Matter
4% Ordinary Matter- The _____ matter that makes up you and me
26% Dark Matter- __________ matter that doesn't interact with light. We know its there because of it's ____________ effect on ordinary matter. It pulls things together.
70% Dark Energy- Invisible energy that causes the universe to ____________. It pushes things apart.