Transcript Lecture 1, PPT version

AS102 -The Astronomical Universe
Instructor: Professor Tereasa Brainerd
TAs: Ren Cashman & Katie Garcia
AS102 - Major Topics
• Where are we (earth, sun) in the universe?
• What are stars?
• How are stars born, how do they live out their lives and how do
they die?
• What is the Milky Way?
• What are galaxies, and what can they tell us about the universe
as a whole?
• Has the universe always existed? If not, how did it begin?
The boring details…
Class web page is http://firedrake.bu.edu/AS102/AS102.html
Textbook: Stars, Galaxies & Cosmology (5th edition) by Bennett,
Donahue, Schneider and Voit
Grade Breakdown:
Labs (best 5 of 6 day labs + 2 night labs): 25%
Homework (approx. 10, 2 lowest scores dropped): 15%
Midterm Exams (15% each, best 2 of 3): 30%
Final Exam: 30%
In-class “minute papers”: 5%
Day Labs - Rooms B4 & 606
Text of day labs will be posted on the course web page.
You are responsible for printing out hard copies of the labs and bringing
them to your lab section!
Luminosity & Brightness (B4)
Parallax (B4)
Gravity (B4)
Spectroscopy (B4)
Stellar Spectra (Computer Lab, 606)
Hubble Law (Computer Lab, 606)
Next week: 2/19-2/21 will be orientation and math review in lab sections.
Night Labs - Roof of CAS Building
Every CLEAR Monday,
Tuesday, and Thursday night
starting at 8:30pm
Call 617-353-2630 after
6:00pm for status of night labs.
Night Lab #1 - must attend
one session between 01/19
and 03/4
Night Lab #2 - must attend
one session between 03/15
and 04/27
Night lab reports are due by 5:00pm on the day after the last scheduled
opportunity to do the lab (03/05, 04/28)
The eastern view from the roof.
Notice the red brick wall on the bottom and the
concrete wall to the right.
Wear lots of warm clothes (including a hat and gloves)! You will
be outside on the roof for about an hour.
Bring a small flashlight! It will be dark, and you will need to write
things down during the lab.
Get your night labs done as early as you can!
• Night lab #1 is only offered before Spring Break
• Night lab #2 is only offered after Spring Break
• If you wait until the very last night to go up to the roof, and it
happens to be cloudy (or snowing) that night, you’re out of
luck and will get a zero on the night lab
candy
Homework Assignments
• will be due about every other
week
• will be posted on course web
page
• hand in using the “Homework
Box” in the main Astronomy Office
(Room 512/514)
• your two lowest scores
(including zeros due to illness) will
automatically be dropped
• late homework is not accepted
In-class “Minute Papers”
• Last 5 minutes of class (12:15pm to 12:20pm) write a few
sentences on one of the following: something you found
particularly interesting in the day’s lecture, something you
found particularly confusing in the day’s lecture, questions
you have about topics that were covered in the day’s lecture
• Use a full-sized sheet of paper (8.5”x11”)
• Be sure to print your name clearly
• You can miss up to 3 minute papers (due to illness or family
emergency) without it affecting your grade
Physics & Mathematics
•
Astronomers use laws of physics to interpret observations of the
universe
•
Physics is a mathematical description of nature
•
Focus will be on qualitative understanding, but will be times when
we need to use mathematics
•
Math will be at level of high school algebra
•
Will practice ratios, units conversion, powers of 10 next week in lab
•
Get a copy of Prof. Marscher’s math primer from the course web
page
How to succeed in this course…
• Come to class every day, do the labs, do the homework, and
hand everything in on time
• Read along in the book (see the lecture outline in the syllabus)
• Start studying early for exams
• Ask lots and lots of questions!!!!
Exam Dates
• Midterm #1 - Thursday, February 11
• Midterm #2 - Tuesday, March 23
• Midterm #3 - Tuesday, April 20
• Final Exam - Tuesday, May 5 (9:00am - 11:00am)
Astronomy as a Science
• What is the “scientific method”?
• What makes a good “theory”?
• Does the scientific method have an endpoint? Why or why not?
• In what way is astronomy a “passive” science compared to other
sciences (e.g., chemistry, biology)?
Learning about the Universe
(where do the data come from?)
It’s all about LIGHT!
Light comes in
different “colors”
Light interacts with
matter
The Solar System
Sun is a perfectly ordinary,
garden-variety star. Mass of
2x1030 kg, about 5 billion
years old.
Earth is one of 8 planets that orbit the
sun. Planets closest to the sun are
hard and rocky. Planets farthest from
the sun are huge gas balls. Is there
anything special about the Earth’s
location?
Stars in the Night Sky
Look closely at this picture on the course website. The projector does not do it justice!!
What differences might you see? Do all stars seem the same?
Baby Stars
Star Guts
The Milky Way
Time exposure image taken at the
Cerro Telolo observatory in Chile.
What’s the little bright blob on the
horizon?
Our home galaxy is called the
“Milky Way Galaxy”. It is a vast
collection of stars, gas (mostly
hydrogen) and dust.
M31 (the Andromeda Galaxy)
our “sister” galaxy
Like the Milky Way,
M31 is a spiral
galaxy where most
of the stars reside
in a thin disk.
The sun resides in
the outer reaches
of the Milky Way’s
disk.
Any idea where all
the stars you see
around M31 are
actually located?
M51 (the Whirlpool)
Take a look at this
on the course web
page. This is one
of the most
beautiful galaxies in
the universe!!!
Bright blue stars
are extremely
young
Bright pink blobs
are hot hydrogen
gas
Notice how they
all fall along the
spiral arms!
Not all galaxies are spirals
M87 - a giant elliptical galaxy
The Large and Small Magellanic
clouds (irregular galaxies)
The universe is full of galaxies!
An image of an essentially
random region of the sky.
There are over 2000
galaxies in the image, and
in the entire universe there
are at least 100 billion
galaxies in the
observable universe.
Minute Paper
A few sentences on one of the following:
* something you found particularly interesting today
* something you found particularly confusing today
* questions on things from today that you would like to know more about
Be sure to PRINT your name legibly