Trotter 2013-2014

Some Vocabulary Geocentric: Earth centered Astronomical unit Heliocentric : sun centered Perihelion Aphelion Copernicus

Early Astronomy 280 BC- Aristarchus (Greek) stated that the Sun was the center of the 'solar system'. It was almost 1800 yrs later that his theory would be widely accepted. Heliocentric: sun centered Geocentric: earth centered

Heliocentric vs geocentric Planetary motion could not be explained with a geocentric model. Mars’ retrograde motion proved this.

Galileo Galilei (1564-1642) The Italian physicist and astronomer first used a telescope from lenses he made himself, at the beginning of the 17th Century. Again, he stated that the Sun was the center of the universe, for this he was persecuted for going against the Church. The Inquisition forced him to repeal his discoveries in order avoid torture. He also discovered sun spots and Jupiter's 4 satellites.

Isaac Newton (1643-1727) He coined the now famous term "and to every action there is always an equal and opposite or contrary, reaction." Newton also determined the moon's effect on the tides.

Edwin Hubble (1889-1953) He discovered that our Milky Way was not the center of the universe, but rather only one galaxy in among billions. He calulates the distance to the Andromeda and Triangulum 'nebulas'. He also theorized that the galaxy was expanding.

Who’s Kepler? 17th century astronomer and mathematician Described astronomy as “ celestial physics” Born in 1571

Kepler’s Law of Planetary Motion Law 1: Ellipses Law 2: Equal Areas Law 3: Periods

Law 1: Law of Ellipses The Earth, planets, asteroids, and some comets orbit the Sun in an elliptical path Earth travels faster when it is closest to the sun ( perihelion), and slower when its farther away (aphelion) The Sun is at one focus

I. Measuring Light A. Light is the best tool astronomers use to learn about the universe. 1. Analyzing the radiation emitted from foreign cosmos scientists first have to understand the radiation

II. Radiation A. The radiation astronomers study is called electromagnetic radiation. 1. Electromagnetic radiation has both a electric & magnetic wave components as it travels through space B. This radiation has various wavelengths which include: infrared, ultraviolet, radio, microwaves, x-rays, gamma & visible light

V. Types of Telescopes A. There are 2 types of telescopes: located at high altitudes to diminish atmosphere coverage 1. Refracting – (1600) focuses visible light with lenses 2. Reflecting – (1668) focuses visible light using mirrors. Widely used today FYI: Radio telescopes – dish acts like a reflecting telescope

VI. Telescopes At Other Wavelengths A. Special designed reflecting telescopes have been created to help collect infrared, x-rays, ultraviolet. 1. Receiver collects & converts the waves into signals that can be stored & analyzed by a computer B. Scientists also linked different telescopes together, called interferometry, to act as one. 1. Allows for a clearer picture of information

VII. Satellites, Probes & Space-Based Astronomy A. Astronomers send their instruments into space to collect the information since Earth’s atmosphere blocks a lot of space radiation. B. Sending instruments into space allows for a clearer picture as well as close-up (obtain samples) from nearby objects. C. Spaced-Based observatories: 1. Hubble telescope 2. Space Probes (Spirit & Opportunity)

IIX. Human Space Flight A. Space Shuttle Program (1981) B. International Space Station