Download Astronomy: The Original Science

Chapter 18
Section 1
Astronomy: The Original Science
1 Describe two early ideas about the structure of
the universe.
2. Describe the contributions of Brahe, Kepler,
Galileo, Newton, and Hubble to modern astronomy
Log: Sept. 20th
• Suppose that you need to explain the
concepts of a year, a month and a day to a
small child. Write a paragraph and draw a
picture describing the motion of the earth.
Our Modern Calendar
• Year- the time it takes
the earth to orbit the
sun
Day
• The circumference of the Earth at the
equator is 25,000 miles.
• The Earth rotates in about 24 hours.
• Therefore, if you were to hang above the
surface of the Earth at the equator without
moving, you would see 25,000 miles pass by
in 24 hours, at a speed of 25000/24 or just
over 1000 miles per hour.
Day- the earth rotates once on its axis
Month- the time it takes the moon to
orbit the earth
Early Astronomy
• Ptolemy (Toleme)
– Greek astronomer
– Earth center of
universe
• Copernicus
– Polish
– Sun centered universe
• Tycho Brahe
– Danish Astronomer
– Late 1500s
– Sun and moon
revolved around the
Earth
– Other planets revolved
around the sun
• Johannes Kepler (yo
hon ees)
– Brahe’s Assistant
– All planets revolved
around the sun in a
elliptical orbit
– Laws of Planetary
Motion
1st law
• I. The orbits of the planets are ellipses,
with the Sun at one focus of the ellipse.
Galileo: Telescope
• One of the first to use a telescope
• Discovered
– Sun spots
– Craters & mountains on moon
– Planets are not wandering stars
Isaac Newton
• Explained the laws of gravity
• Gravity depends on mass
Edwin Hubble
• 1924
• Proved other galaxies exist beyond milky way
Log: Sept. 21st
• Describe month, day and year.
• If you need trade with someone and evaluate
their Buried Treasure Directions
• Start DR
Fold CHart
Ptolemy
Copernicus
Tycho
Kelpler
Galileo
Newton
Month
Day or Year
Drawing
3 facts
Log: Sept. 22nd
• Create a time line using the astronomers that we have learned
about. Use you text to find what year the wrote their theories.
Ptolemy
Galileo
Tycho
Kelpler
Copernicus
Hubble
Newton
What instrument did Tycho use to make discoveries?
Log: Sept. 23
• Explain why early astronomers thought the
planets were wandering stars?
• List the 4 discoveries of Galileo.
Telescopes
Chapter 18 Section 2
Sept. 3 Log: Do Now
• What are the two main types of optical
telescopes
• List one difference between the two
Used to look at outer space
Optical telescope
• Most common Telescope used
• Collects visible light an focuses it to a focal point
– Focal Point- the point where rays of light pass through lens or
reflect from mirror
– Objective lens- collect light and forms image at back of telescope
• The bigger the more light it can gather
– Eye piece- magnify the image produce by objective lens
History of two
Telescopes
• Galileo and his
• Newton’s Reflective
Refractive Telescope
Telescope
Refracting-
This is the simplest telescope design you
could have. A big lens gathers the light and directs it to a focal
point and a small lens brings the image to your eye.
Refractors are the type of telescope that most of
.
us are familiar with. They have the following parts:
1. a long tube, made of
metal, plastic, or
wood
2. a glass combination
lens at the front end
(objective lens)
3. a second glass
combination lens
(eyepiece)
• What are the
disadvantages look on
pg. 559 in book
Refractive Disadvantages
• Lens focus different colors of light a different
distances
• Size of telescope is limited to size of objective
lens
• If to large glass will sag due to its own
weight
Most professionals use
Most commonly used in homes
Reflecting
• Many Advantages
• Mirrors can be very
large
• Mirrors are polished
on one side a prevent
light from entering
• Can focus all colors of
light at same focal
point
Used a curved mirror to
gather and focus light
Reflecting
• Some Disadvantages
• Atmosphere still disrupts star light
• Light pollution form cities can still disrupt
images
Best places to stargaze
• Area away from city light
• Mountains
• Outer space
http://www.ifa.hawaii.edu/mko/
Some very large reflecting telesopes
Hubble Space Telescope
• Orbits in outer space
• Is a reflective telescope
• Deployed in 1990
Homework
• Drawing Refractive
• List
– Advantages
– Disadvantages
• Draw Reflective
• List
– Advantages
– Disadvantages
Log: Sept. 27th
• List 3 types of Nonoptical telescopes.
• Explain what they are best used for.
Write the question and answer in
log
• What does the water drop do to words on
the paper?
• James Clerk 1852
– Proved visible light is only part of the
electromagnetic spectrum
– The Spectrum is made up of 7 different types
of radiation
All of the frequencies or wavelengths of electromagnetic radiation
Nonoptical Telescopes
• Detect radiation that can not be seen by the
human eye
– Radio
– Infrared
– X-ray
– Gamma Ray
– Ultra Violet
Today Class work
• Complete DR in class
• Define words on Telescope Diagram
• If needed Complete for HW
Telescopes
Optical
Reflecting
Non Optical
Refracting
Ultra Violet
Gamma Rays
Radio
Infrared