1. Astronomy Review

2. HOW SCIENTISTS BELIEVE THE SOLAR SYSTEM FORMED
The Big Bang Theory:
The universe began with a big explosion some billion years ago
All matter was condensed into a tiny spot and for some reason it exploded and formed what we know as the universe … evidence for this theory is that the universe is still expanding and being formed.

3. HERE’S WHY SCIENTISTS BELIEVE THE UNIVERSE IS EXPANDING
RED SHIFT

4. LIFE CYCLE OF A STAR STAGE 1: NEBULA
A Nebula is a cloud of dust and gas.
Nebulae are the birthplace of stars.
HORSESHOE NEBULA

5. STAGE 2: Main Sequence Star
Our sun is a main sequence star
STAGE 3: Giant or Supergiant
A supergiant burns cool so it glows red
STAGE 4: White Dwarf
This is very small (about the size of Earth), hot star, the last stage in the life cycle of an average size star like the Sun.

6. Hertzsprung-Russell Diagram
(H-R diagram)
Stars are ranked based on their temperature and absolute magnitude.
O B A F G K M

7. *Note the position of the sun in the Milky Way
GALAXIES
There are 3 types: Elliptical, Irregular and Spiral
Spiral
Identified by its spiral arms
The Milky Way is a spiral galaxy of about 200 billion stars
*Note the position of the sun in the Milky Way

8. THE SUN Layers of the Sun Photosphere
this is the visible surface of the Sun
the layer where most of the
light comes from
2. Chromosphere
only visible during a solar
eclipse or with special filters…
appears as a red circle or ring
around the sun during the
eclipse

9. 3. Corona
only visible during a solar eclipse or with special filters…appears as white glow that extends several million miles into space

10. Sunspots Cooler areas on the photosphere that last for about 2 months
Sunspot cycle occurs about every 11 years

11. THE INNER PLANETS

12. VENUS
Second from the Sun and similar to Earth in size and mass, therefore known as EARTH’S TWIN
Has an extremely dense atmosphere of clouds, therefore making it the hottest planet in the solar system

13. LAYERS OF THE ATMOSPHERE
THE EARTH
LAYERS OF THE ATMOSPHERE
Which layer does weather occur in?
Where do you find the ozone layer?
Where do you find the jet stream?

14. Troposphere: weather,
clouds, and smog are found here

15. Stratosphere contains the ozone (O3) layer The ozone layer can be
depleted by chlorofluorocarbons
also known as (CFC’s).
CFC’s contribute to global
warming
The Jet Stream is also found in the Stratosphere

16. EARTH’S TILT CAUSES SEASONS
The hemisphere tilted toward the Sun receives more daylight hours than the hemisphere tilted away from the Sun therefore:
When the North Pole is in the sunlight, the Northern Hemisphere is having SUMMER.
When the North Pole is in darkness, the Northern Hemisphere is having WINTER.

17. SOLSTICES
The day when the Sun reaches its greatest distance north or south of the equator
1. Summer Solstice---occurs June 21 or 22 in the northern hemisphere
2. Winter Solstice---occurs December 21or 22 in the northern hemisphere
SUMMER SOLSTICE WINTER SOLSTICE

18. EQUINOXES The day when the Sun is directly over Earth’s equator
12 hours of daylight and 12 hours of darkness on equinox days
1. Spring equinox occurs on March 20 or 21 in the northern hemisphere
2. Fall equinox occurs on September 22 or 23 in the northern hemisphere
FALL (Autumnal) EQUINOX SPRING (Vernal) EQUINOX

19. PHASES OF THE MOON New Moon Waxing Crescent Waning Crescent
1st Quarter rd Quarter
Waxing Gibbous Waning Gibbous
Full Moon

20. ASTEROID BELT
Made from rocks that are similar to that which formed planets
Most asteroids lie in an asteroid belt located between Mars and Jupiter

21. THE OUTER PLANETS THE GAS GIANTS
Are made completely of gas, and may have a solid core
Are the largest of all the planets in the solar system
Have numerous moons and very thin atmospheres

22. JUPITER fifth planet from the Sun largest planet in the solar system
a stormy ball of mostly hydrogen
and helium
the Great Red Spot is the most spectacular of Jupiter’s many constant high-pressure gas storms… winds up to 400 m/hr

23. SATURN
Sixth planet from the Sun, second largest in the solar system, lowest density…it would float on water if you could find a big enough tub
Thick atmosphere of hydrogen and helium

24. COMETS Made of dust and rock mixed with water, methane, and ammonia
As it approaches the Sun, its structure changes
The icy comet begins to vaporize
Solar winds push on the gases in the comet
Tails always point away from the sun