ASTR 220 - Collisions in Space
Homework 1 (12 points)
Homework is due at 11AM
on the lecture date indicated on the syllabus.
Homework handed in
after 11AM on the due date will be considered late (a 2 point deduction).
Homework turned in after the due date will lose additional points, but partial
credit is better than none at all. Late homeworks will NOT be accepted after
graded homeworks have been returned.
Due Tuesday February 15 at the beginning of class
Homework MUST be neat, meaning typed, word-processed, or very neatly
hand written. We must be able to read and understand your homework for
you to receive full credit. SHOW your calculations on any problems and JUSTIFY
written answers - `yes' or `no' is not adequate. Do NOT COPY from the book
or the Web. This is plagiarism and violates the University honor code. Though
readings in the book may be the basis of your answer, it is important to
phrase all answers in your own words. Do NOT COPY from a fellow student.
This is academic dishonesty. You may discuss homework with friends, but the
final product must be your own work.
If you make use of references other than the textbooks or class handouts,
include the reference information (book title & author; WWW URLs) at
the end of your assignment. The University's honor code will be enforced.
See page 36 of the Schedule of Classes.
Homework 1 Questions:
Describe the orbit of a typical comet. Relatively speaking,
how much time does it spend near to and far from the sun?
What happens as a comet nears the sun that sometimes makes
- Observed Crater Densities:
Satellites (moons) and planets with solid surfaces show great variation
in the number of craters that are visible. Describe the processes which
can modify a surface which started out with many craters when the
solar system was young (4 billion years ago).
- Make use of the WWW tool
Astronomical Distances to answer the following questions:
- a) How long would it take you to reach the Moon if you traveled in
a spaceship as fast as a car? As fast as a commercial airliner? Choose
typical values for these speeds. If you are unsure of typical speeds,
- b) How many times further away is Pluto than our Moon? How many times
further away is Proxima Centauri than Pluto? How many times further away
is the center of the Milky Way than Proxima Centauri? (HINT: how is the
ratio of travel times related to the desired ratios of distances?)
- c) A club popular with all space faring species in the galaxy is
Joe's Canteen and Deuterium Depot, conveniently located at the center of
the Milky Way. Joe's is particularly noted for its delectable
FAF (Flaming Arcturian Flamingo). Alas, the Arcturian Flamingo has been
placed on the Galactic Endangered Species List. This news
will reach Joe's in 25,000 years, where there will no doubt be one last
great multi-species interstellar feast. If you
leave Earth now and make the best possible speed, can you make it in time
to eat FAF at Joe's?
Why or why not?