Transcript Linking Asteroids and Meteorites through Reflectance Spectroscopy

Astronomy 101
The Solar System
Tuesday, Thursday
2:30-3:45 pm
Hasbrouck 20
Tom Burbine
[email protected]
Course
• Course Website:
– http://blogs.umass.edu/astron101-tburbine/
• Textbook:
– Pathways to Astronomy (2nd Edition) by Stephen Schneider
and Thomas Arny.
• You also will need a calculator.
Office Hours
• Mine
• Tuesday, Thursday - 1:15-2:15pm
• Lederle Graduate Research Tower C 632
• Neil
• Tuesday, Thursday - 11 am-noon
• Lederle Graduate Research Tower B 619-O
Homework
• We will use Spark
• https://spark.oit.umass.edu/webct/logonDisplay.d
owebct
• Homework will be due approximately twice a
week
Homework #1 (Email it to me if you
have not submitted it)
• Find an article concerning a topic concerning the
Solar System and write about why you found it
interesting.
• Include the name of the article and where it was
published.
• Submit using Spark
Homework #2 (due today)
• 10 questions
• In Assessment on Spark
HW #3 (due Thursday)
• 10 questions
• In Assessment in Spark
Let’s look at the sky
• http://www.skyandtelescope.com
Terminology for looking at the sky
Celestial Poles
• The altitude of the celestial pole (near Polaris) is
equal to your latitude
• If the altitude of the celestial pole is 50 degrees,
you latititude is 50 degrees
Angular size
• We measure distances
in the sky using angles
• 180o in the observable
sky
More precise distances
• 1 degree = 60 arcminutes (symbol ´)
• 1 arcminute = 60 arcseconds (symbol ´´)
• So something that is 2 degrees, 10 arcminutes, 22
arcseconds would be written as
• 2o 10´ 22´´
Star positions change versus latitude
Astrology
• Astrology by birth sign or sun sign means that
your particular horoscope characteristics are
based mainly upon the location of the sun's
astrological position in the zodiac at the time of
your birth.
Aries (21 March - 20 April)
• Arians have a tendency to act like a dynamo of energy
when they set their mind on achieving some goal. They
can sometimes act so quickly that they later discover that
they should have put in just a little more thought before
starting. Action and achievement are important and slow
pokes that get in the way, watch out! Aries may step on
your toes. Aries enthusiasm rubs off onto others and they
get involved in something, others are ready to follow.
Selfishness, which sometimes includes a need to control
others, tarnishes their otherwise positive and adventurous
spirit. They need to have empathy and concern for the
needs of others. As a lover, they are passionate, giving
and enterprising.
Seasons
• You an use the location of different constellations
in the sky to tell what season it is
Video
• http://www.learner.org/resources/series28.html
Precession
• Gravity-induced, slow and continuous change in
an astronomical body's rotational axis
• Gradual shift in the orientation of Earth's axis of
rotation, which, like a wobbling top, traces out a
cone in a cycle of approximately 26,000 years
http://en.wikipedia.org/wiki/File:Earth_precession.svg
http://calgary.rasc.ca/images/radec_earth_precession.gif
Implications
• Polaris won’t always be the North Star
http://en.wikipedia.org/wiki/File:Lunar-Phase-Diagram.png
Eclipses
Moon is tilted at an angle of 5 degrees to Earth’s orbit
• http://astronomyonline.org/SolarSystem/LunarEcl
ipse.asp
Color of lunar eclipse
• The Moon does not completely disappear because of the
refraction of sunlight by the Earth’s atmosphere
• If the Earth had no atmosphere, the Moon would be
completely dark during an eclipse.
• The red color arises because sunlight reaching the Moon
must pass through the Earth’s atmosphere, where it is
scattered.
• Shorter wavelengths are more likely to be scattered by the
small particles. By the time the light has passed through
the atmosphere, the longer wavelengths dominate. This
resulting light reflected from the Moon we perceive as red.
Solar eclipse
http://en.wikipedia.org/wiki/Image:Solar_eclips_1999_4_NR.jpg
• Solar eclipses occur approximately every 18 months
• However, they recur (on average) at any given place only
once every 370 years
• Moon's umbra moves eastward at over 1,700 km/hr
• Every year, there are at least two lunar eclipses.
• Can be viewed anywhere on the night side of the Earth
http://home.cogeco.ca/~astrosarnia/Photos/Lunar%20eclipse%20binocular.jpg
Solar eclipse of July 22, 2009
• Lasted a maximum of 6 minutes and 39 seconds
off the coast of Southeast Asia
http://upload.wikimedia.org/wikipedia/commons/f/f2/Solar_eclipse_animate_%282009-Jul-22%29.gif
http://en.wikipedia.org/wiki/File:Solar_eclipse_22_July_2009_taken_by_Lutfar_Rahman_Nirjhar_from_Bangladesh.jpg
Models
• When you have a model of how something works,
you should be able to predict what will happen
• If observations do not fit the model, either the
observations or the model is wrong
• The ancient astronomers wanted to predict the
positions of planets in the sky
What did the ancients think
• That the Earth was the center of the universe
• That the celestial sphere was rotating around the
Earth
• However, there was two observations that caused
problems with this idea
– Apparent retrograde motion
– Inability to detect stellar parallax
Greek model
Apparent Retrograde Motion = “backward” motion
Retrograde Motion
Retrograde
• Planet appears to go backwards in its orbit
Stellar Parallax
• Stellar Parallax – The apparent shift in the
position of a nearby star (relative to distant
objects) that occurs as we view the star from
different positions in the Earth’s orbit of the Sun
each year
The distance the star moves is greatly exaggerated in this figure.
Stellar parallax can only be seen by a telescope.
Ancient astronomers could not detect
stellar parallax
• If Earth orbited the Sun, ancient astronomers
believed that they would see differences in
angular separation of stars as the Earth rotated
around the Sun
• Since they saw no changes in angular separation
of the stars, they assumed the Earth was the center
of the universe
• They could not fathom that stars are so far away
that stellar parallax is undetectable by the human
eye
Any Questions?