Astronomy 3 Lecture 17
more moons, measuring stars
In fact, Io is the most volcanically active world in
the solar system.
How can this be?
a differential gravitational force
All Galilean satellites have synchronous rotation about Jupi
Questions to answer:
What are jovian planets made of?
What is their internal structure?
What is the weather like on jovian planets?
Bigger than Earth, and with more mass than Earth
Lower density, so different composition from Earth
Rings (all four hav
Messenger Spacecraft image
Astronomy 3 Lecture 12
More on Terrestrial planets, atmospheres
The UCLA Meteorite Gallery
room 3697, Geology Building
Why are the cores
Astronomy 3 Lecture 18: Characteristics of Stars
Scores posted in my.ucla gradebook
Standard deviation: 15%
Grading: A/B border mid to high 80s
B/C border - ~70
< 60? (17 of you) - co
Astronomy 3 Lecture 11: more on exoplanets,
" " " " " " " " the inner solar system
Last point on star formation its not simple
Four ways to find planets:
Radial velocity: planet's orbit makes star wobble
Transits: planet blocks a bit of starlight
Astronomy 3 <><><><> Lecture 3
Textbook expected in bookstore Thursday or Friday
you can purchase the e-book at:
click sign in or regi
of the course
1) to elucidate the origins of our planet Earth in the context of structure
formation in the universe, star formation in our Galaxy, and planetary system
formation. Where did we come from?
2) To demonstrate that science is not a body
Astronomy 3 Lecture 4:
Understanding Planetary Motions
This is Charon,
The moon of Pluto.
Half the diameter of Pluto
1/10 the size of Earth
Right Ascension & Declination
Like latitude and longitude on the Earth.
Declination is the angle
Astronomy 3 -=-=-=- Lecture 2: the Sky Around Us
The quiz do the reading first !
Access to the class website
Distance Scales, using light as a reference
(light travels about 300,000 km per second)
The Jovian Planets
The Gas Giants
The outer planets have no solid surface, and are much bigger. The
primary gases are hydrogen and helium (like the Sun), although
Uranus and Neptune have substantial (15 Earth mass) rock/ice
The Formation of the Solar System
1. As of October 10, 2014 - 1832 planets in
1145 planetary systems found around other
stars so far. There are 469 multiple planet
2. All are more massive than Earth. Many are
more massive than
Brown, A 1
a) F=GMm/r2 and F=ma
MEarth = 6 x 1027g and REarth = 6.3 x 108cm
MMoon = 7.3 x 1025g and RMoon = 1.7 x 108cm
5.98 = Fearth/Fmoon
610 27 g 7108 cm 2
21030 g 6.3108 cm
1. It is hypothesized that the layered structure of Earth must have developed when the Earth was
young and molten. During this time the denser materials (ex: iron) sank deeper than the lessdense ones. On page 121 in the book, it says that the m
1. The Suns surface temperature is about 5800K and its spectrum peaks at 5000 A. An O-type
stars surface temperature may be 40,000K.
a) According to Weins law, at what wavelength does its spectrum peak?
peak = 2.9 x 107 K / 40,000 K = 725
1. Based on the image, I believe that the angle covered by the star trails is about 30 degrees. It is
hard to know exact but based on the picture that is my guess. Since we are taking exposure based
on stars, I believe the sidereal day is appro
A solar day is a full revolution with respect to the sun. A sidereal day is a full revolution with
respect to background stars. In the normal case, when the Earths spin and orbit are
counterclockwise, the sidereal day is shorter. In the proposed case,
1. P12/ P22 = a12/a22 2002/12 = a3/13 = 34. 1995au
It is likely that this comet came from the Kuiper belt. Do to the fact that its orbit period
and semi-major axis are within the range for the Kuiper belt.
P12/ P22 = a12/a22 100,0002/12= 2,154.
Astro C10, Spring 2016
Kelpers and Newtons Laws
1. Keplers First Law: The orbit of any planet is an ellipse with the Sun at one of the
DIRECTIONS: In the space below, draw the elliptical orbit of one planet around a star.
Label the planet, the star,
Astro 10: Keplers and Newtons Laws SOLN
Keplers First Law
Your drawing should look something like Figure 1 with the semi-major axis being half of the
major axis that is shown.
Figure 1: ellipse
Keplers Second Law
Keplers second law is
Foundations of Modern
Astronomy: Galileo and Isaac
An ellipse is an example of
a conic section. Circles
and hyperbolas are others.
All are possible forms for
You can make an ellipse with 2
tacks and a string. The tacks a
Isaac Newton and the
Laws of Motion and
Newtons Three Laws
1) The Law of Inertia: objects will move at a constant
velocity unless acted upon by forces. (really Galileos
law). Note that the velocity of an object cha
Isaac Newton (1642 - 1727)
Perhaps the greatest physicist (natural philosopher)
of the 17th and 18th centuries. Wrote important works on light,
mechanics, and gravity. He invented calculus (independently invented
by Leibnitz in Germany at more
Tycho Brahe (1546 - 1601)
Tycho was an outgoing, arrogant man who once claimed that he
was the greatest observer of the heavens who ever lived, but the
greatest who ever would live. He was partially right.
Tycho had become famous as an astronomer and unde
Why are there 24 hours in a day?
Hours freed people from the timelessness of the
Goes back to the Egyptians and is related to
their division of the zodiac into 36 decants and
their use in determining time. At the solstices 18
Observer based - different for every observer
Horizon - where the sky meets the sea
Zenith - point directly overhead (easy to
Altitude angle from the horizon up to a
Azimuth angle m
Adaptive optics, coordinate
How about making 2 separate telescopes behave as though they were 2 pieces of one
much larger telescope. You get the larger ones resolution, but not its light-gathering
power. The light from the
Lecture 2 Leo Blitz waves,
particles and the
How do we get
What, exactly, is light?
What are its properties?
Lets consider waves and particles.
What are those pesky
LectureProf. Absorption and
5 Leo Blitz
Emission Lines; Telescopes
Energy Levels in Atoms
We can think of an atom as consisting of a positive nucleus (protons
and neutrons) surrounded by negative electrons. The electrons can
be thought of as
Lecture Prof. TheBlitz
3 Leo Doppler Shift
and Blackbody Radiation
The Spectrum of E-M radiation
Astronomical objects are capable of producing different parts of the
spectrum depending on how energetic the processes that are going
on, or how