our universe billions of galaxies made up of billions of stars
TRANSCRIPT
Our Universe
Billions of galaxies made up of billions of stars
Our Own Solar System
The Sun and the Planets that orbit it
The Sun – Our StarThe closest star to Earth
• Medium size • Yellow • Main Sequence Star• 150,000,000 Km (93
Million miles) away.• 4.5 - 5 billion years old• Will last about another
5 billion years• Located near the edge
of our disc shaped galaxy – The Milky Way
The Suns PlanetsCelestial bodies that orbit a star
Our Milky Way Galaxy
CometsRocky material made of gas dust and ice that orbit the
sun
MeteorsSpace Rocks known as shooting stars when they
enter the Earth’s atmosphere.Become meteorites when they hit the Earth’s surface
AsteroidsSmall rocky bodies known as minor planets
Orbit the sun mainly between Mars and Jupiter (asteroid belt)
StarsHuge bright balls of gas
What are Stars?
• Gigantic spheres of gases held together by gravity
• Generate huge amounts of energy because of nuclear reactions of hydrogen and other elements.
• Radiate electromagnetic radiation.– Light, heat and other forms of energy
• There are 100 billion stars in our own galaxy!
Stars• The Sun is the closest star
to Earth – 150,000,000 km away
• The next closest star is Proxima Centauri – 39,900,000,000,000 km away– 4.2 light years
• Stars are extremely far away!!!
• The Sun is thousands of times closer to Earth than other stars
• The Sun
• Proxima Centauri
Light YearsUnit of measurement for distances in Space
• The distance that light travels in one year.• Light travels at about 300,000 km/sec.
– 186,000 miles/sec
• One light year is equal to 9.46 trillion km (9,461,000,000,000).– 5.87 trillion miles (5,870,000,000,000)
• Light travels faster than anything else known to man.
Classifying Stars
Class Color Surface Temp.(degrees Celsius)
Elements detected
Examples of stars
O Blue Above 30,000 Helium 10 Lacertae
B Blue-white 10,000 - 30,000 Helium and Hydrogen
Rigel, Spica
A Blue-white 7,500 - 10,000 Hydrogen Vega, Sirius
F Yellow-white
6,000 - 7,500 Hydrogen and heavier elements
Canopus, Procyon
G Yellow 5,000 - 6,000 Calcium and other metals
The sun, Capella
K Orange 3,500 - 5,000 Calcium and Molecules
Arcturus, Aldebaran
M Red Less than 5,000 Molecules Betelgeuse,Antares
Hertzprung–Russel (H-R) Diagram- a graph that shows the relationship between a star’s
surface temperature and it’s absolute magnitude.
H-R DiagramAnalyze the graph!
Analyzing the H-R Diagram
Brightest Stars
Y-AxisBrightness
Dimmest Stars
Hottest Stars X-Axis Coolest Stars
Temperature
Stages of a Stars Life Cycle
Nebulas – Stellar Nurseries
• Giant clouds of gas and dust in space
• Where new stars are formed
GALAXIESLarge group of stars in space held
together by GravityClassified by Shape - Sprial/Disc, Elliptical, Irregular
Shaped
Spiral/Disc Shaped Galaxy
• Andromeda Galaxy – Large center with spiral arms traveling around it
– Ex. Andromeda Galaxy and our Milky Way Galaxy
– Our Sun is located near the edge of the Milky Way Galaxy
Our Milky Way• Sprial/Disc
Shaped Galaxy• 100,000 Light
Years Across• Black Hole at the
center• The Sun is near
the edge of our galaxy in one of the spiral arms.
Elliptical Galaxy
• M 87 Galaxy
– Massive blobs of stars that have very bright centers
– Very little gas and dust
– Contain mostly old stars.
Irregular Galaxy
• Large Megellanic Cloud
– Don’t fit into any other class.
– Have irregular shapes
– Contain mostly young stars and lots of gas
SupernovaDeath of a star by explosion
Black HolesGravity is so strong not even light can escape
Believed to be the center of most galaxies
Theories on the Origin of the Universe
How did we get here?• The Big Bang Theory – states that
the universe began with a big explosion.
• Steady State Theory - the universe has always been here and always will.
• There are many more theories
The Big Bang Theory
• Most dominant theory
• States that the universe was created from a cosmic explosion that hurled matter in all directions
• Occurred about 13-14 billion years ago
Evidence that supports the big bang
• Cosmic background radiation – radiation coming from all directions in
space, believed to be left over from the big bang.
• The observable expansion of the universe (Red Shift).– Galaxies are moving away from each
other
Spectroscopes/Spectrometers
•Used to gain information about properties of components in the Universe
•Shows differences in the elements that make up a star.
Electromagnetic Waves
• Light Waves that Astronomers can use to gain information about distances and properties of components of the universe.
Electromagnetic Waves
• Radio waves• Microwaves• Infrared waves• Visible Light • Ultraviolet waves• X-Rays• Gamma Rays• Cosmic Rays
From lowest to highest frequency (energy)
Electromagnetic Waves Research
1. Look up Electromagnetic Waves using your netbook.
2. Define electromagnetic waves3. List all the electromagnetic waves in
the electromagnetic spectrum4. Describe what each type of wave is
used for by humans.