The Solar SystemASTR 1010

Tu/Th 12:30-1:45PM, Room 202

by Inseok Song

Lecture #1

Physics / Astronomy “majors”…

go out and see Mr. Tom Barnello (Room 310)to be enrolled in ASTR1110 instead!

I am an exo-planet hunter!

1st Imaged Exo-planetary system !

… trying to understand the origin of planetary systems• In Pleiades, collision between two

planets!

Gemini Planet Imager (GPI) • The largest scale exoplanet imaging

project in the world.o 1000 hrs of “clear” observing time

with the 8m telescopeo 34 million USD for manufacturing

highly specific instrument for exoplanet imaging

o will observe about 1,000 nearby stars to image orbiting planets

about $34,000 / star

o Need to prepare the best set of targets

• I am the leader of the target selection group for GPI

First Day of the Class

• Professor: Inseok Song • Office : Physics Building, Room 240 Office Telephone Number: 706-542-7518• E-Mail Address: song@uga.edu • Course Webpage:http://cosmos.physast.uga.edu/iSong/ASTR1010

• Office Hours: Tue/Thu after the class or by appointment

Check the course webpage frequently!

http://www.physast.uga.edu “course schedule” ASTR1010

Why Astronomy?

“… it is better to be a human being dissatisfied than a pig satisfied” - John Stuart Mill, 19th century British philosopher

beautiful

extreme

curiosity

past

future

Vast Universe

Vast UniverseHubble Ultra Deep Field: in a very small region of the sky (similar to the angular extent of a penny at the end of a football field), ~10,000 galaxies were found.

Vast Universe : Hubble Ultra Deep FieldIn the Universe, there are about 10 billions galaxies!And, each galaxy has about the same number of stars as in the Milky WaySo, there have to be Earth-like planets somewhere out there…Yet, we are barely reaching out the boundary of Solar System with our technologyIt is very difficult to explore distant space, let’s first know the details of our Backyard!

Astronomy• To understand the Universe, astronomers are using scientific methods.

Characteristics of Science1. Collection of facts (or observations)2. Create/test a model to explain observations3. Make a testable prediction4. After successful predictions, it becomes a theory

models should be as simple as possible. Occum’s razor examples: a model of the atom, a model of the solar system…

Through numerous tests/verifications, theory becomes law.

Pseudo-Science

Pseudo-science : handling the nature appearing as a true science, but it involves a non-scientific handling of evidence or method.(Ex) Biorythm: every human being has three distinct cycles (physical: 23 days, emotional: 28 days, intellectual: 33 days) which determine the fate of an individual.

Scientific… in your daily life

Say that you are looking for a used car, and you are offered a lovely, 1-year old Porsche for just $500.

?Why should the price so low? ?Does the car run??Has it been wrecked and poorly rebuilt?

Ask your friendTake a test driveGet examined by a mechanic you trust

being scientific : skeptical and looking for greater confidence in a drawing conclusion.

fact

skepticism

test

draw a new conclusion

Tentativeness : Being “Scientific” is not absolute!• 200 years ago, French Academy of

Science declared that the notion of stones falling from the sky (e.g., meteorites) by Chladni is not scientific; a complete nonsense.

why? Scientific evidence for this hypothesis (claim) is lacking…

Then, the claim by Ernst Chladni received a spectacular confirmation by a prominent meteor shower near L’Aigle, France in 1803.

Scientific or not?? Thanks to Isaiah Crowell, UGA will win the season opening game against

Boise State on Sep 3, 2011.? Terrestrial bacteria can survive on Mars.? A huge fleet of alien ships will land on Earth and introduce an era of peace

and prosperity on January 1, 2020.? There is no liquid water on the surface of Venus today.? My house is haunted by ghosts, who makes the creaking noises I hear each

night.? God created the Universe with all Laws of Nature (e.g., Law of Motion,

evolution, etc)

Logic and clarity are the most important!Does not matter if it is right or wrong!

Laws of Physics• Proven physical theories that survived numerous tests over time are

referred to as “Laws of Physics”

these can have profound effect on civilization.

“Newtonian Theory of Gravity” or “Newtonian Mechanics” immediate practical application in the construction of machines, buildings,

bridges, etc.

Theoretical and mathematical advances triggered by Astronomy led to the Industrial Revolution.

Formation of the solar system• By exploring the planets in our solar system, we can uncover the clues to

the origin of the Solar System.o Solar System = the Sun and all celestial objects orbiting the Sun (planets, moons,

asteroids, comets, and more)o From accumulated knowledge from various space missions in addition to the

Moon rocks brought back by Apollo mission, we now know that our Solar System has been shaped by numerous collision among its constituents.

o Age of the Solar System: How do we know? the oldest rocks on the Earth 3.9 billion years old (3.9 Gyr) oldest object found on Earth 4.56 Gyr meteorites deduced the age of Solar System to be ~4.56Gyr

Stars are born, age, and die• By studying stars, astronomers discover how stars are born, age, and die.

What powers stars?

Forming Stars (massive star formation site)

Orion Nebula (about 400 parsecs or 1300 Lyrs away)

Exploded star

Crab nebula(supernova seenin 1054 AD)

about 6000 Ly away

From galaxies to the Universe

• By observing galaxies, astronomers learn about the origin and fate of the universeo all galaxies are moving away

from us and from each other expanding Universe Big Bang

(Right) Image of a star and a quasar that are drastically different in nature.star : ~100 Ly awayquasar : 9 billion Lyr away

In summary…

Important Concepts• Science

observables hypothesis testable prediction theory

Important Terms• Occum’s razor• Laws of Physics• Nebula• Nuclear burning (or H-burning)• quasar

Chapter/sections covered in this lecture : sections 1.1-1.4