Welcome to AST 2002H

AST 2002H General Comments Hard class, but also fun. Lots of resources: Attend class Keep up with lectures, quizzes, online resources Office hours Einstein Club and Preceptors (more on this later) SARC tutors and workshops Online Resources Mastering Astronomy comes with the new book, new features for students as well as for instructor. Specific instructions from publisher. Unique aspects of honors section: Small class atmosphere conducive to discussions Can go into more depth on certain subjects

AST 2002H General Comments Mastering Astronomy: Course ID: AST2002HF10 Free help available for Mastering Astronomy: "virtual" office hours with AIM Screen Name ast2002help on Tuesdays, 1:30 - 2:30 pm and Thursdays, 9:00 - 10:00 am. Additionally, students may use this email address: (ast2002help@gmail.com), appointments to see students in person are also available.

AST 2002H General Comments (Cont.) Class Mechanics: Syllabus has all the relevant information, READ IT! The Essential Cosmic Perspective (5th edition) by Bennett . The Mastering Astronomy code comes with the book at the UCF bookstore. MAKE SURE you get this code if you buy the book elsewhere. 4 Exams: 3 in-class (Thursday Sept. 23, Thursday Oct 21, and Tuesday Nov 23), and a cumulative final (on Tuesday Dec. 7 at 1:00 PM) Grades: 100% exams, plus extra credit (see below)

IV. Class Mechanics: EXTRA CREDIT Participate in the Einstein Club To get extra credit you MUST complete 90% of the assigned quizzes (you can miss no more than 1 quiz). If at end of semester the quiz requirement is fulfilled, extra credit will be earned for several activities: Quiz grades can add as much as 1% to course grade Meet once a week until Nov. 17th with a preceptor (to qualify for this 1% extra credit you cannot miss more than two of these weekly meetings with preceptors). Attending a workshop at UCF's Student Academic Resource Center (SARC, Phillips Hall Room 113) BEFORE Nov. 17th, can add 1%. All this can add up to 3% to your course grade!

Other: Please turn off cell phones, never answer them in class Do not be shy about asking questions in class, it makes the lecture much more interesting Seek help outside class (office hours, preceptor, tutor at SARC) Attendance is very important. Unannounced in-class quizzes. Exams will be based on material covered in class Read chapters BEFORE CLASS, review and study THAT DAY after class Not a stargazing class, more like physics of the universe Course gets harder: get a good grade on the first exam because its hard to recover later

Who cares about astronomy anyway?

Outline of lecture 1 (Ch 1) 1.1 Our modern View of the Universe Survey of the universe and powers of ten 1.2 The scale of the Universe Astronomical distances 1.3 Spaceship Earth Motions of Earth, Sun, Galaxies

1.1 Our Modern View of the Universe Our goals for learning: What is our place in the universe? How did we come to be? How can we know what the universe was like in the past? Can we see the entire universe?

Start with Earth-Moon and jump 100 times larger every slide

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DISTANCE SCALES ASTRONOMICAL UNIT (AU): Earth Sun. The average distance between the Earth and the Sun. About 150 million km or 93 million miles Earth 1 AU Sun.

A TOUR OF THE SOLAR SYSTEM KUIPER BELT AND OORT CLOUD NOT TO SCALE!!!! ASTEROID BELT MERCURY NEPTUNE EARTH JUPITER SATURN URANUS VENUS PLUTO MARS

A TOUR OF THE SOLAR SYSTEM KUIPER BELT AND OORT CLOUD Distance (AU) .4 .7 1.0 1.5 5 10 20 30 40 ASTEROID BELT MERCURY NEPTUNE EARTH JUPITER SATURN URANUS VENUS PLUTO MARS NOT TO SCALE!!!!

DISTANCE SCALES LIGHT-YEAR (LY): The distance light can travel in one year. About 9.5 trillion km NOTE: this is a distance not a time! How far is the nearest star?

DISTANCE SCALES LIGHT-YEAR (LY): The distance light can travel in one year. About 9.5 trillion km NOTE: this is a distance not a time! How far is the nearest star? 4.3 Ly

WRITING NUMBERS IN SCIENTIFIC NOTATION CONVENTIONAL SCIENTIFIC NOTATION 341,000 3.41 X 105 0.0000049 4.90 X 10-6 234,000,000 2.34 X 108 0.0134 1.34 X 10-2

1.1 Our Modern View of the Universe Our goals for learning: What is our place in the universe? We are on a planet, orbiting a star, in a galaxy (which is a member of the Local Group of galaxies in the Local Supercluster) How did we come to be? How can we know what the universe was like in the past? Can we see the entire universe?

STAR A large, glowing ball of gas that generates heat and light through nuclear fusion

PLANET A moderately large object which orbits a star; it shines by reflected light. Planets may be rocky, icy, or gaseous in composition.

The definition of a planet is not so clear What about Pluto? What about objects larger than Pluto that have been discovered? What about asteroids? The definition of a planet is not so clear (it was much easier for the ancient Greeks….for them a planet was a star that moved and there were 5 of them)

MOON An object which orbits a planet.

ASTEROID A relatively small and rocky object which orbits a star.

COMET A relatively small and icy object which orbits a star.

SOLAR (STAR) SYSTEM A star and all the material which orbits it, including its planets and moons

NEBULA An interstellar cloud of gas and/or dust

GALAXY A great island of stars in space, all held together by gravity and orbiting a common center

THE UNIVERSE The sum total of all matter and energy; that is, everything within and between all galaxies

AGE OF UNIVERSE Age of Universe: about 14 billion years Age of Solar System: about 4.6 billon years Cosmic Calendar: see details in book

1.1 Our Modern View of the Universe Our goals for learning: What is our place in the universe? We are on a planet, orbiting a star, in a galaxy (which is a member of the Local Group of galaxies in the Local Supercluster). How did we come to be? The matter in our bodies came from the Big Bang, which produced hydrogen and helium. All other elements were constructed from H and He in stars and then recycled into new star systems, including our solar system. How can we know what the universe was like in the past? Can we see the entire universe?

Where do we come from? The first (and simplest) atoms were created during the Big Bang. More complex atoms were created in stars. When the star dies, they are expelled into space…. to form new stars and planets! Most of the atoms in our bodies were created in the core of a star!

SPEED OF LIGHT The speed of light in the vacuum of space is constant! All light travels the same speed! c = speed of light = 290,000,000 m/sec = 2.9 x 108 m/sec = 290,000 km/sec

Looking back in time Light, although fast, travels at a finite speed. It takes: 8 minutes to reach us from the Sun 8 years to reach us from Sirius (8 light-years away) 1,500 years to reach us from the Orion Nebula The farther out we look into the Universe, the farther back in time we see!

1.1 Our Modern View of the Universe Our goals for learning: What is our place in the universe? We are on a planet, orbiting a star, in a galaxy (which is a member of the Local Group of galaxies in the Local Supercluster). How did we come to be? The matter in our bodies came from the Big Bang, which produced hydrogen and helium. All other elements were constructed from H and He in stars and then recycled into new star systems, including our solar system. How can we know what the universe was like in the past? When we look to great distances we are seeing events that happened long ago because light travels at a finite speed. Can we see the entire universe?

1.1 Our Modern View of the Universe Our goals for learning: What is our place in the universe? We are on a planet, orbiting a star, in a galaxy (which is a member of the Local Group of galaxies in the Local Supercluster). How did we come to be? The matter in our bodies came from the Big Bang, which produced hydrogen and helium. All other elements were constructed from H and He in stars and then recycled into new star systems, including our solar system. How can we know what the universe was like in the past? When we look to great distances we are seeing events that happened long ago because light travels at a finite speed. Can we see the entire universe? Nope!

1.1 Our Modern View of the Universe Our goals for learning: What is our place in the universe? We are on a planet, orbiting a star, in a galaxy (which is a member of the Local Group of galaxies in the Local Supercluster). How did we come to be? The matter in our bodies came from the Big Bang, which produced hydrogen and helium. All other elements were constructed from H and He in stars and then recycled into new star systems, including our solar system. How can we know what the universe was like in the past? When we look to great distances we are seeing events that happened long ago because light travels at a finite speed. Can we see the entire universe? No, the observable portion of the universe is about 14 billion light-years in radius because the universe is about 14 billion years old. ALSO (not in Ch. 1 of the book), we can “see” only about 4% of the universe, 96% is made of “dark matter” and “dark energy”.

What have we learned? How is Earth moving in our solar system? It rotates on its axis once a day and orbits the Sun at a distance of 1 AU = 150 million km How is our solar system moving in the Milky Way Galaxy? Stars in the Local Neighborhood move randomly relative to one another and orbit the center of the Milky Way in about 230 million years

What have we learned? How do galaxies move within the universe? All galaxies beyond the Local Group are moving away from us with expansion of the universe: the more distant they are, the faster they’re moving Are we ever sitting still? No!