Download File

Astronomy
Notes
Image From: http://www.astronomy-pictures.net/spiral_galaxy.jpg;
1 of 11
Stars
• An object made of gas that gives off energy
– mainly hydrogen
– helium
The Sun
•
•
•
•
medium in size & life span compared to other stars
primary energy source for all processes on Earth
much closer to Earth than any other star!
about 4 ½ billion years old
H-R Diagram: Shows the relationship between
color, temperature, magnitude & size of stars.
Magnitude
• Color = temperature
• Magnitude = how bright
• Our Sun is a main sequence star.
2 of 11
Black Dwarf
Nebula
1. Large
cloud of
gas & dust
where
stars form.
2. Gravity pulls
4. Outer layers
5. Collapses
material into a
come off
sphere that
to just its
3. Expands
becomes
core
dense, hot
Explodes!
& ignites.
3 of 11
4 of 11
Galaxy
• A large grouping of stars in space.
• 3 types
1. Spiral – bulge in center & distinctive spiral arms
•
•
Example: Our galaxy, The Milky Way
Our solar system is located within an arm
2. Elliptical – spherical or elongated
3. Irregular
1
2
3
Our Solar System
5 of 11
Terrestrial Planet: a rocky, INNER planet
Mercury
• closest to the sun
• no atmosphere
• full of craters
• very hot during day; freezing cold at night
Venus
• Similar in size to Earth
• Hot, thick & poisonous atmosphere
Earth – home!
Mars
• known as the “red planet” because of its ironrich soil
6 of 11
Gas Giant: large, OUTER planet that is
made mostly of gases
Jupiter
• largest planet
• known for its storm, “The Great Red Spot”
Saturn
• known for its ring system
Uranus
• known for blue-green atmosphere
Neptune
• blue-green atmosphere like Uranus
• Also has a storm, “The Great Dark Spot”
Moon
7 of 11
• A natural satellite of a planet.
• The outer planets have many of them!
Image From: http://sos.noaa.gov/images/Solar_System/moon.jpg;
Definition: www.thefreedictionary.com
Other Rocky Bodies...
Asteroids
• asteroid belt between Mars & Jupiter
• small, rocky body that revolves around the Sun
Meteoroids – in space (like asteroids), but usually smaller
Meteors – (meteor shower); a bright streak of light caused by the
rock burning as it streaks through the atmosphere
Meteorites – piece of rock that has landed on Earth without
completely burning up, possibly making a crater
Comet – a body of ice, rock and dust that
forms a tail as it gets close to the Sun
8 of 11
Light Year
A measure of how long it takes light to
travel through space in one year.
Image From: http://uniqhorns.com/images/milkyway.gif;
Definition: www.thefreedictionary.com
9 of 11
10 of 11
Electromagnetic Spectrum
The range of all the waves that can travel
through matter as well as empty space.
R
O
Y
G
B
I
V
Scientists use different
portions of the spectrum to
learn about the universe.
Ex: light waves can tell us
what elements stars are
made & if they are moving
away or towards other
objects.
Image From: http://www.lcse.umn.edu/specs/labs/images/spectrum.gif
Definition: www.thefreedictionary.com
Theories on the Origin of the Universe
1. Steady State – has always been the same
2. Oscillating Model - began by expanding, has
slowed down & is now contracting
3. Big Bang - *the dominant theory
• 12 to 15 billion years ago
• Universe began as a dense point that exploded
• It rapidly expanded & began to cool down,
forming stars, etc.
• Evidence
 discovery of cosmic background radiation
 red shift in EM spectrum suggest it is still expanding
11 of 11