1. Studying Science
Chapter 1

2. Astronomy: The Original Science
Section 1 Vocabulary
Astronomy
Year
Month
Day

3. Introduction
Seasonal cycles of the stars, planets, and the moon to mark the passage of time
Best times of year to plant and harvest crops
Observatories
Study of the universe
Led to first calendars

4. Our Modern Calendar
Based on the observations of bodies in our solar system
Time required for the Earth to orbit once around the sun
Roughly the amount of time required for the moon to orbit around the Earth
The time required for the Earth to rotate once on its axis

5. Who’s Who of Early Astronomy
Helped people understand their place in the universe
Oral histories
Discovered with their eyes and minds
Stars edge of the universe
Ptolemy and Copernicus

6. Ptolemy: An Earth-Centered Universe
140 CE –book that combined all the ancient knowledge of astronomy that he could find
Ptolemaic theory
Earth was at the center of the universe and the other planets revolved around Earth (geocentric)

7. Copernicus: A Sun Centered Universe
1543-New theory that will eventually revolutionize astronomy
Sun is at the center of the universe (heliocentric)
Did not replace Plotemaic theory immediately
Coperinican Revolution

8. Tycho Brahe: A Wealth of Data
Late-1500’s-several large tools to make the most detailed astronomical observations
Different geocentric model
Sun and moon revolve around Earth
Planets move around the sun

9. Johannes Kepler: Laws of Planetary Motion
Brahe’s assistant –continued his work
Did not agree with his theory
1609-all of the planets revolve around the sun in elliptical orbits and the sun is not in the exact center of the orbits.
3 laws of planetary motion

10. Galileo: Turning a Telescope to the Sky
1609-one of the first people to use a telescope to observe objects in space
Craters and mountains on the Earth’s moon
Four of Jupiter’s Moons
Sunspots on the Sun
Phases of Venus
Not “Wandering Stars” but physical bodies

11. Isaac Newton: The Laws of Gravity
1687-all objects in the universe attract each other through gravitational force
Force of gravity depends on the mass of the objects and the distance between them
Explained why we travel around the sun

12. Modern Astronomy Edwin Hubble: Beyond the Edge of the Milky Way
Two Milestones
Invention of the Telescope
Description of Gravity
Before the 1920’s –thought the Milky Way (our galaxy) included every object in space
1924-proved that other galaxies existed beyond our galaxy
Computers help process data and control the movement of telescopes

13. Telescopes Section 2 Vocabulary Telescope Refracting Telescope
Reflecting Telescope
Electromagnetic Spectrum

14. Introduction Standard tool
Professional astronomers
Amateur stargazers
An instrument that gathers electromagnetic radiation from objects in space and concentrates it better for observation

15. Optical Telescopes Most common Helps to see so much more in the sky
Study visible light from objects in the universe
Helps to see so much more in the sky
Collects visible light and focuses it to a focal point for closer observation
The point where the rays of light that pass through the lens or that reflect from a mirror coverage

16. Optical Telescopes Simplest telescope has two lens
1. Objective Lens- collects light and forms an image at the back of the telescopes
The bigger the lens
The more light can gather
2. Second lens-located in the eyepiece of the telescope
Magnifies the image produced by the objective lens

17. Refracting Vs. Reflecting
Refracting Telescopes
Reflecting Telescopes
Telescopes that use lenses to gather and focus light
Objective lens that bends light that passes through it and focuses the light to be magnified by an eyepiece
Two Disadvantages
Cannot be perfectly focused
Size is limited due to the objective lens
Telescope that uses a curved mirror to gather and focus light
Light enters the telescope and is reflected from a large curved mirror to a flat mirror
Flat mirror focuses the image and reflects the light to be magnified
Advantages
Mirrors can be very large
Prevents light from entering the glass
Focus all colors of light to the same focal point

18. Refracting Vs. Reflecting
Refracting Telescopes
Reflecting Telescopes

19. Very Large Reflecting Telescopes
Several mirrors work together to collect light and focus it in the same area
Hawaii
Twin telescopes
36 hexagonal mirrors that work together
Linking several mirrors-more light to be collected and focused in one spot

20. Optical Telescopes and the Atmosphere
Light gathered by telescopes on the Earth is affected by the atmosphere
Atmosphere
Causes starlight to shimmer and blur due to the motion of the air above the telescopes
Light pollution from large cities can make the sky look bright
Places for telescopes
Dry areas
Mountaintops

21. Optical Telescopes in Space
Hubble Space Telescope
2.4 meters across
Can detect very faint objects in space

22. The Electromagnetic Spectrum
Visible light
Light that we can see
Not the only form of radiation
1852-James Clerk Maxwell proved that visible light is part of the electromagnetic spectrum
Made up of all of the wavelengths of electromagnetic radiation

23. Detecting Electromagnetic Radiation
Each color of light is a different wavelength of electromagnetic radiation.
We can see
Red light-long wavelength
Blue light-short wavelength
Rest of electromagnetic spectrum-radio waves, microwaves, infrared light, etc.
Atmosphere blocks most invisible radiation
Can pass through-radio waves, microwaves, visible light, etc.

24. Nonoptical Telescopes
To study invisible radiation
Detect radiation that can not be seen by the human eye
Each type of radiation reveals different clues about an object

25. Radio Telescopes Detect Radio waves
Much larger than optical telescopes –radio waves are much longer than optical wavelengths
Most can be detected day and night
Does not have to be solid

26. Linking Radio Telescopes
More detailed images
Work like on large telescope
Very Large Array
27 radio telescopes
30km

27. Nonoptical Telescopes in Space
Most blocked by the earth’s atmosphere
Put a lot of them in space
Chandra X-Ray Observatory
Detects X-Rays
Much more sensitive

28. Mapping the Stars Section 3 Vocabulary Constellation Zenith Altitude
Horizon
Light-year

29. Patterns in the Sky Ancient cultures connected stars in patterns
Named sections of the sky based on the patterns
Sections of the sky that contain recognizable star patterns
Help navigate and keep track of time
Different civilization-different names
Orion

30. Constellations Help Organize the Sky/Seasonal Changes
A Region in the sky
Shares a border with its neighbor
Like states
Every star or galaxy is located within 1 of 88 constellations
As the Earth revolves around the sun, the apparent locations of the constellations change from season to season.

31. Finding Star in the Sky
Astrolabe-can be used to describe the location of a star or planet-Used on relation to you
Need to know three points of reference
Zenith
Altitude
Horizon
If you want to describe a star’s location in a relation to the Earth, you need to use the celestial sphere

32. The Path of Stars Across the Sky
Most stars and planets rise and set throughout the night-apparent motion is caused by the Earth’s rotation
Poles- the stars are circumpolar
Stars that can be seen at all times of the year and all times of night
They never set.
Different areas of the universe are visible

33. The Size and Scale of the Universe
Looking out a car window at trees
Objects that are very far away do not appear to move at all
Same for stars and planets
1500’s-Nicolaus Coperinicus noted that the planets appeared to move relative to each other but the stars did not
Thought that the stars must be much farther away than the planets

34. Measuring Distance in Space
Copernicus was correct.
Light-Year-Unit of length equal to the distance that light travels in 1 year
9.46 trillion kilometers
Farthest objects we can observe are more than 10 billion light-years away

35. The Doppler Effect Car Horn Doppler Effect-also occurs with light
If a light source is moving quickly away from an observer, the light emitted looks redder than it normally does
Redshift
If a star is moving quickly toward an observer its light appears bluer than it normally does
Blushift

36. An Expanding Universe
Hubble-analyzed the light from galaxies and stars to study the general direction that objects in the universe are moving
Light from all galaxies except our close neighbors is affected by redshift
Rapidly moving away from each other
All galaxies except our close neighbors are moving apart, the universe must be expanding