Do Now 2/18/141. Which moon phase comes after a waxing

gibbous?2. Which layer of the Sun do we see?3. Where does the sun’s energy come from

(how is it made)?

We’re taking a quiz. . .

The Visible Universe

The Milky WayGalaxy

The Solar System (that blue dot is Earth)

The Earth

1) List them in order from largest to smallest2) list them in the order they were formed

3. What direction do those normally spin?

4. What force cause the “Spinning Disk” to form clumps because of the crashes and collisions?

5. Is the Milky Way spherical or spiral in shape?

6. Is the Universe expanding?

7. What is the name of the most accepted theory for the formation of the Universe?

8. How old is the Universe?

9. What does the rotation of the Earth cause?

10. What do the Revolution and Precession of the Earth cause?

Time to Grade. . .

Proof of the Big Bang, Kepler’s 3 Laws and the History of Astronomy

Astronomy

• The “Golden Age of Astronomy” occurred during 600 – 150 B.C. when the ancient Greeks used observations, instruments, and geometry and trigonometry to make the first discoveries of space.

Aristotle (384 – 322 B.C.)

Determined that Earth was round based on the curved shadow left on the surface of the moon when Earth fell between the sun and the moon.

Eratosthenes' measurement of the Earth's circumference

• Eratosthenes calculated the circumference of the Earth without leaving Egypt. Eratosthenes knew that on the summer solstice at local noon in the Ancient Egyptian city of Swenet (known in Greek as Syene, and in the modern day as Aswan) on the Tropic of Cancer, the sun would appear at the zenith, directly overhead (he had been told that the shadow of someone looking down a deep well would block the reflection of the Sun at noon). He also knew, from measurement, that in his hometown of Alexandria, the angle of elevation of the sun was 1/50th of a circle (7°12') south of the zenith on the solstice noon. Assuming that the Earth was spherical (360°), and that Alexandria was due north of Syene, he concluded that the meridian arc distance from Alexandria to Syene must therefore be 1/50 = 7°12'/360°, and was therefore 1/50 of the total circumference of the Earth. His knowledge of the size of Egypt after many generations of surveying trips for the Pharaonic bookkeepers gave a distance between the cities of 5000 stadia (about 500 geographical miles or 927.7 km). This distance was corroborated by inquiring about the time that it takes to travel from Syene to Alexandria by camel. He rounded the result to a final value of 700 stadia per degree, which implies a circumference of 252,000 stadia. The exact size of the stadion he used is frequently argued. The common Attic stadion was about 185 m,[9] which would imply a circumference of 46,620 km, i.e. 16.3% too large. However, if we assume that Eratosthenes used the "Egyptian stadion"[10] of about 157.5 m, his measurement turns out to be 39,690 km, an error of less than 2%.[11]

Eratosthenes’ measurements

Models of the Solar System

1. Geocentric Model – The Greeks determined that the moon, the sun, and the known planets (Mercury, Venus, Mars, and Jupiter) orbited Earth.

2. Heliocentric Model – Aristarchus (312-230 B.C.) was the first Greek to believe in a sun-centered universe.

Ptolemaic System – Claudius Ptolemy 141 A.D. He used the geocentric model, but was the first to explain retrograde motion (the planets move eastward in the sky, appear to stop, move backwards, and then resume its eastward movement).

http://www.youtube.com/watch?NR=1&v=72FrZz_zJFU&feature=fvwp

The Birth of Modern Astronomy

Nicolaus Copernicus (1473-1543) – The first major astronomer to make advancements since Ptolemy. He was the first to determine that Earth is a planet and that the sun is the center of the universe.

Tycho Brahe (1546-1601) He convinced King Frederick II to build an observatory in Copenhagen. Here, Brahe invented measuring devices (telescopes had not yet been invented) and made the most accurate observations of several planets, especially Mars.

Johannes Kepler (1571-1630) – Studied under Brahe and continued his work by using math to develop 3 laws of planetary motion.-The path of each planet around the sun is an ellipse.

Kepler’s 1st Law Of Planetary Motion• Each planet moves in an

ellipse rather than a circle–Perihelion-When a planet is

closest to the sun–Aphelion-When a planet is at

it’s furthest distance from the sun

Kepler’s 2nd Law Of Planetary Motion

• Kepler’s second law says that an imaginary line between the sun and a planet sweeps out equal amounts of area in equal amount of time

Kepler’s 2nd Law Of Planetary Motion

Kepler’s 3rd Law Of Planetary Motion

• States that the planet’s orbital period squared is equal to its mean solar distance cubed:– T2 = d3, where T = planet’s

orbital period and d = solar distance

– Therefore, the solar distances of the planets can be calculated when their periods of revolution are known.

Gallileo Galilei (1564-1642) –first to use the telescope. Found 4 satellites (moons) around Jupiter.Realized planets are circular disks, not just points of

light.Venus has phases (just like our moon does).The sun has sunspots (dark spots).

-Sir Isaac Newton (1642-1727) developed the Law of Universal Gravitation.

-The gravitational pull is a result of the mass of the object and the distance between 2 objects.

Reward Video Time

• Earth’s motion around the sun

• http://www.youtube.com/watch?v=82p-DYgGFjI&feature=related

Exit Ticket 2/18/14

Think of a way that you could teach the seasons to a class of middle school students.

Draw your ideas or write them out on your white sheet of paper.

**Make sure to include how they will understand the tilt causes the seasons and how they will be able to recognize each season based on a photo.

Do Now 2/13/14

1. What happens to most of the light energy during photosynthesis?

2.A major piece of scientific evidence supporting this

theory is the fact that wavelengths of light from galaxies moving away from Earth in stage 3 are observed to be:

a) shorter than normal (a red shift)b) shorter than normal (a blue shift)c) longer than normal (a red shift)d) longer than normal (a blue shift)