1. How would you send a letter across the universe
How would you send a letter across the universe? What’s your return address?

2. Galactic Address, Galaxies, and Stars

3. There’s no place like home…
Powers of Ten video
What is your galactic address?

4. Galactic Address Name Room 227 Cinnaminson Middle School Cinnaminson
Burlington County
New Jersey
United States of America

5. North America
Northern Hemisphere
Earth
Solar System
Milky Way Galaxy
Local Group
Virgo Supercluster
Universe

6. Galaxies
A large group of stars (million+), gas, and dust held together by gravity.

7. 4 shapes of galaxies
Spiral-normal
Spiral-barred
Elliptical
Irregular

8. Spiral - Normal

9. Spiral - Barred

10. Elliptical

11. Irregular

12. The Milky Way What happens when galaxies collide?

13. Stars

14. What is a star?

15. What is a star?
A star is an object in space that produces its own light and heat through nuclear reactions.

16. Size of Stars
Stars can be as small as Earth or as large as the orbit of Jupiter.

17. Surface Features

18. Surface Features
Sunspots - cooler, darker areas.

19. Surface Features
Flares – erupting columns of gas caused by sunspots.

20. Surface Features
Prominences - arching columns of gas

21. Not the actual location of Earth
Prominences
Not the actual location of Earth

22. Surface Features
Coronal Mass Ejections (CME’s) – electrically charged particles sent towards Earth.

23. CME’s Can disrupt radio, satellite, and phone use.
Also causes auroras to occur.

24. CME’s
Earth’s magnetic field helps protect us from the CME’s.

25. Constellations

26. What is this constellation?

27. Cassiopeia

29. Constellations Constellations are patterns of stars in the sky.
Stars are organized into 88 constellations.

30. Constellations
Constellations can help identify directions in the sky and time of year.

31. Constellations
Constellations also may tell a story.

33. Star Classification

34. Observe a candle flame What colors do you notice?
Why are there different colors?
How does a candle look up close? Far away?

35. Classification
Stars are organized by temperature and brightness.

36. Temperature
Hot stars are blue-white
Cool stars are red-yellow

37. Brightness
Absolute Magnitude - a measure of the actual amount of light given off by a star (watts)
Apparent Magnitude - a measure of the amount of light seen from Earth. (how bright it looks)
100 Watts
50 Watts

38. Do the stars of Orion have the same apparent or absolute magnitude?

39. Not all stars are equal distances away, but their apparent magnitudes look the same from Earth

40. Star Distance Star distance is determined using parallax
Parallax - how much a star appears to “jump” when viewed from two different positions
Measuring the universe

41. H-R Diagram
H-R Diagram - a chart used to classify stars based on temperature and absolute magnitude (brightness).

42. bright
brightness
dim
temperature
hot
cool