1. SSA Review # 1 - Astronomy

2. Universe - Space and all of the matter and energy that is in it.

3. UNIVERSE
GALAXY
STARS
SOLAR SYSTEMS
PLANETS

4. *Galaxy – a massive system of stars (billions), gases, dust, and other matter held together by a central gravitational force

5. Spiral Elliptical
Irregular

6. *Stars – large spherical(round) bodies composed of gas (H, He) and gives off light
The Sun
Sirius
Betelgeuse
Aldebaran
Regulus

7. *Solar System – a central star with planets and other small objects orbiting it

8. *Planet – a spherical body that orbits a star

9. Measuring Distances in the Universe

10. *Astronomical Unit (AU’s) – the distance from Earth to the Sun
--used to measure distances in the Solar System

11. *Light year – the distance light travels through space in 1 year of time (measures distances in the rest of the Universe)
From Earth to stars
The size of galaxies
From galaxy to galaxy

12. Size of Stars

13. *The color of a star indicates its temperature
Blue (Hottest) Red (Coolest)

14. *Apparent Magnitude - How bright a star appears to be from Earth
The Sun
26.8
Sirius
-1.46
Vega
+0.03
Betelgeuse
+0.5
*The smaller the number (value), the brighter the star appears

15. *Absolute Magnitude (Luminosity) – How bright a star actually is
Apparent Magnitude
Absolute Magnitude
The Sun
26.8
+4.8
Sirius
-1.46
+1.2
Vega
+0.03
+0.6
Rigel
+0.12
-8.1
Betelgeuse
+0.5
-7.2
*The smaller the number (value), the brighter the star actually is

16. Models of the Solar System

17. *Geocentric Model – Earth in the center

18. *Heliocentric Model – Sun in the center

19. Structure of the Sun
Core where energy is produced through the process of fusion

20. Structure of the Sun
Convective Zone – Energy moves to the surface by convection currents

21. Structure of the Sun the visible surface of the sun
Photosphere
the visible surface of the sun
Structure of the Sun
*approx 300 miles thick
*takes 8 minutes for light to reach the
Earth

22. The Sun’s Rotation – Differential Rotation
*Different parts of the sun rotate at different rates of speed (the sun is a ball of gases , not solid like the Earth

23. SOLAR ACTIVITY
Solar Flare an explosive burst of energy extending out from the sun
*appears as very bright spots on the photosphere
*Similar to a volcanic eruption on Earth

24. SOLAR ACTIVITY
Prominence huge loops of gases extending out from the sun
*many Earths could fit inside one

25. SOLAR ACTIVITY Sunspots dark areas that form on the sun’s surface
*cooler regions of the photosphere caused by a change in the sun’s magnetic field

26. *How does solar activity affect conditions on Earth?
*Solar flares can affect satellites, astronauts, GPS systems, jet airplanes, and electrical systems and devices on Earth.

27. 1 - Inner Planets
(Terrestrial)
*Small
*Rocky
*Thin atmospheres
*Closer to the Sun

28. *Fast rotational period
2 - Outer Planets
(Gas Giants)
*Large
*Thick, gaseous atmospheres (hydrogen & helium) with a solid core
*Fast rotational period
*Many moons and rings
*Farther away from the Sun (colder)

29. 1. Dwarf Planet
*A round object that orbits the Sun, but has other objects that cross its orbit
PLUTO

30. 2. Natural Satellites (Moons)
*A round object that orbits a planet
*Why does Jupiter and Saturn have so many satellites?
*They have a stronger gravitational pull on objects

31. 3. Asteroids
*Chunks of rocks & metal orbiting the Sun

32. 5. Comets
*An icy body that releases glowing gases as it orbits close to the Sun
Coma
Tail

33. What is the universal force that hold galaxies together, caused a nebula to collapse inward and flatten into a disk that eventually formed our solar system, and keeps objects in orbit around other objects?
Gravity