1. Two Basic Groups of PlanetsTwo Basic Groups of Planets
TERRESTRIALTERRESTRIAL
Small sizeSmall size
Low MassLow Mass
Higher densityHigher density
Mostly rockMostly rock
Mercury, Venus, Earth,Mercury, Venus, Earth,
MarsMars
JOVIANJOVIAN
Large sizeLarge size
MassiveMassive
Low densityLow density
Mostly gasMostly gas
Jupiter, Saturn,Jupiter, Saturn,
Uranus, NeptuneUranus, Neptune
2. Mercury is only Slightly LargerMercury is only Slightly Larger
than the Moonthan the Moon
MERCURY
OUR MOON
3. Mercury’s iron core takes up a much largerMercury’s iron core takes up a much larger
percentage its volume than that of Earth.percentage its volume than that of Earth.
4. Venus is covered with a dense
layer of clouds that hides its
surface.
Unlike the benign water vapor
clouds on Earth, these clouds
contain large amounts of sulfur
dust and sulfur compounds, giving
them a yellow-orange color.
The clouds on Venus are made of
concentrated sulfuric acid.
The Clouds of Venus
5. The extreme heating of Venus’ surface isThe extreme heating of Venus’ surface is
caused by the greenhouse effectcaused by the greenhouse effect
The carbon dioxide in
the atmosphere of
Venus acts as a
“greenhouse,”
trapping the heat from
the Sun underneath
and the temperature
rising until finally
thermal equilibrium is
reached…when the
surface is 860°F!
6.
7. Mars Notes
II. Surface Geology
a. Covered by iron oxide
dust (red)
b. Olympus Mons –
largest volcano in the
solar system.
c. Valles Marineris –
Largest Valley in the
solar system (1/5
circumference).
d. More craters than
Earth – Why??
8. Mars also has volcanoes. The largest of these is Olympus
Mons. It covers an area the size of Missouri and rises three
times higher than Mount Everest.
9.
10.
11. Valles Marineris is a giant rift system that would
stretch across the United States. It is about four
miles deep at its deepest point. NASA photo
84-H-595
12. The Martian terrain includes broad towering volcanoes,The Martian terrain includes broad towering volcanoes,
vast windswept plains, and enormous canyons.vast windswept plains, and enormous canyons.
Valles Marineris is a vast canyon
stretchimg over about one-fifth the
circumference of Mars.
14. Mars is tilted on its axis by 25.19° (nearly the same as Earth) and the hemispheres
experience seasons that can be observed by examining the polar caps.
Martian SeasonsMartian Seasons
Large ice cap made mostly of frozen carbon
dioxide (dry ice)
The dry ice melts, leaving a much
smaller polar cap
15. Layers of rock laid down byLayers of rock laid down by
waterwater
Hemetite black rocks, usually
formed in water
Gullies in crater walls
16. Mars Notes
V. History
a. Originally CO2 was more abundant and
the planet was warmer, supporting liquid
water.
b. Water removed CO2 from the
atmosphere and bound it in rocks.
c. Current ice CO2 and H2O.
17. The two moons of Mars, Deimos and Phobos,The two moons of Mars, Deimos and Phobos,
are small and non-spherical in shape. Theseare small and non-spherical in shape. These
are planetesimals captured by Mars.are planetesimals captured by Mars.
18.
19. Astronomers believe that the belts and zones are created by
a combination of the planet’s convection and its rapid
differential rotation.
However, evidence gathered by the Cassini spacecraft
contradicts earlier assumptions about the temperatures
of the gases in the zones and belts. More evidence is
needed to uncover the true nature of these patterns.
20. Jupiter’s clouds move in east-west bandsJupiter’s clouds move in east-west bands
Reddish-colored belts alternate with white-colored zones.
24. Notes
III. Ring King
a. Half mile thick of rock and ice
b. mm to 10m particles
c. Thousands of ringlets (small rings)
d. Cassini Division – large gap (2,500 miles)
28. Uranus Notes
I. Facts
a. First planet discovered by telescope
b. 1781, William Herschel
c. Doing telescopic study of sky, he
noticed something new!!
29. Uranus and NeptuneUranus and Neptune
are Comparable in Sizeare Comparable in Size
URANUSURANUS NEPTUNENEPTUNE
EARTH ONEARTH ON
THE SAMETHE SAME
SCALESCALE
30. The interiors of Uranus and Neptune are both
believed to have the same layers.
36. Notes
II. Long Period Comets: over 1000 year
orbit.
– Originating from Oort Cloud and Kuiper Belt
– Nearby star pulls on material and orbit begins
– Elliptical orbit
37. Many Objects Exist Far Out in theMany Objects Exist Far Out in the
Solar SystemSolar System
Just outside Pluto’s orbit is
a doughnut-shaped region
of the solar system called
the Kuiper Belt.
Beyond this is a
spherically-shaped region
called the Oort Cloud,
which contains billions of
comets.
38. Comets are on highly
elliptical orbits which, if
undisturbed, will have orbital
periods of hundreds of
millions of years. These are
called long-period comets.
However, a close encounter
with a large planet can
deflect the comet into a
smaller orbit around the
Sun. These comets are
called short-period comets.
39. Notes
III. Short Period Comet
– Long period comet pulled in by Jupiter’s orbit
– 150 catalogued
– 70-200 year orbit
– 100 passes close to sun and then evaporates!
42. Meteor Notes
• Meteoroids – Pieces of rock debris in the
solar system.
– May be remnants of comets or asteroids.
43. Meteoroids pulled into our atmosphere by
Earth’s gravity heat the surrounding
gases, causing them to glow.
Thus, they become meteors.
44. Notes
• Meteors
– “Shooting Star”
– Hit atmosphere and burn
– 72 per second hit Earth’s atmosphere
– Average night one sees 6-7/hour
– 60-110 km above Earth
45. During certain predictable times, Earth passes through
sections of its orbit containing debris from a comet,
resulting in a meteor shower.
46.
47. Notes
• Meteorites – Rock debris hitting Earth.
Most likely asteroids or Mars fragments.
– 300 tons per day!
– Pitted Fe or Ni rocks from atmospheric friction
48. Recent Impact SitesRecent Impact Sites
on the Moonon the Moon
On average, 300 tons of mass
(the mass of the obelisk shown
above) is added to the Earth
from meteorites each day.
52. Trees flattened over an area 30km in diameter by theTrees flattened over an area 30km in diameter by the
Tunguska Impact in 1908Tunguska Impact in 1908
58. Life of Low Mass Stars
I. Stars start in a cold nebula (10K)
a. Shock wave from a supernova
compresses the dust and gas of a
nebula into clumps.
b. Gravity causes increased friction and
heat (PROTOSTAR)
59. This radio map shows the extent of giant molecular clouds
in Orion and Monoceros. The locations of four prominent
star-forming nebulae are indicated on the star chart
overlay. Note that the Orion and Horsehead nebulae are
sites of intense CO emission, indicating that stars are
forming in these regions.
Gas- and Dust-Rich Region of Orion
60. Star Formation
2. The central gases are
heating as they fall into the
newly forming a protostar.
1. In a Cold Nebula,
the gravity of dust
and gas pulls
material together.
61. Star Formation
3. As the protostar grows
in mass, its surface gets
brighter while its core
heats up.
4. When little gas is left in
the center of the dark core,
the object becomes a pre–
main-sequence star.
62. Notes
II. Fusion
a. At 10 million K, fusion begins.
b. If enough mass for a chain reaction,
a star is born (CRITICAL MASS)
63. The Pleiades
The blue glow surrounding the
stars of the Pleiades is a
reflection nebula created as
radiation scatters off dust grains.
Most of the cool, low-mass
stars have arrived at the MS,
indicating that hydrogen fusion
has begun in their cores.
64.
65. “Oh, Be A Fine Guy/Girl, Kiss Me!”
Spectral Classes
66.
67. Notes
IV. The end!!
e. RED GIANT compared to sun:
- bright
- cool
- large
f. Nova – “a new.” a flare or burst of gas
given off by a dying star.
68. Planetary Nebulae
Shapes of Planetary Nebulae. The outer shells of dying low-
mass stars are ejected in a wonderful variety of patterns.
NGC 7293,
Helix Nebula
NGC 6826 Menzel 3
96. Galaxy Notes
I. Elliptical Galaxies
EO – Circular
E7 – maximum ellipse
No O,B stars
No active star formation
Many Red Giants
Like galactic bulge of Milky Way
97.
98. Galaxy Notes
II. Spiral Galaxies
Disk and arms with central bulge
Sa – arms tight to center
Sb – arms midway
Sc – arms open wide
99.
100. Galaxy Notes
III. Barred Galaxy (SB)
Bulge in middle is bar shape
Arms open quickly
IV. Irregular galaxy
No shape
LMC and SMC
Editor's Notes
FIGURE 12-5 A Gas- and Dust-Rich Region of
Orion (a) This color-coded radio map of a large
section of the sky shows the extent of giant molecular
clouds in Orion and Monoceros. The intensity of carbon
monoxide (CO) emission is displayed by colors in the order of
the rainbow, from violet for the weakest to red for the strongest.
Black indicates no detectable emission. The locations of four
prominent star-forming nebulae are indicated on the star chart
overlay. Note that the Orion and Horsehead nebulae are sites of
intense CO emission, indicating that stars are forming in these
regions. (b, c) A variety of nebulae appear in the sky around
Alnitak, also called (zeta) Orionis, the easternmost star in the
belt of Orion. To the left of Alnitak is a bright, red emission
nebula called NGC 2024. The glowing gases in emission nebulae
are excited by ultraviolet radiation from young, massive s
Dust grains obscure part of NGC 2024, giving the appearance of
black streaks, while the distinctively shaped dust cloud called the
Horsehead Nebula blocks the light from the background nebula
IC 434. The Horsehead is part of a larger complex of dark
interstellar matter, seen in the lower left of this image. Above
and to the left of the Horsehead Nebula is the reflection nebula
NGC 2023, whose dust grains scatter blue light from stars
between us and it more effectively than any other color. All this
nebulosity lies about 1600 ly from Earth, while the star Alnitak is
only 815 ly away from us. NGC refers to the New General
Catalog of stars and IC stands for Index Catalogs, two
supplements to the NGC. (a: R. Maddalena, M. Morris, J. Moscowitz,
and P. Thaddeus; b: Royal Observatory, Edinburgh; c: R. C. Mitchell,
Central Washington University)
FIGURE 12-9 Star Formation (a) The dark region in this
drawing is of a dark core a few tenths of a light-year across, the
center of which has just developed a Jeans instability. (b) The
central gases are heating as they fall freely and slam into the newly
forming protostar. The surrounding dark core hides this activity
from visible light observations. (c) As the protostar grows in mass,
its surface gets brighter, while its core heats up. (d) When little gas
is left in the center of the dark core to strike the protostar, its
external growth and internal contraction slow significantly and the
object becomes a pre–main-sequence star. (Paul DiMare)
FIGURE 12-9 Star Formation (a) The dark region in this
drawing is of a dark core a few tenths of a light-year across, the
center of which has just developed a Jeans instability. (b) The
central gases are heating as they fall freely and slam into the newly
forming protostar. The surrounding dark core hides this activity
from visible light observations. (c) As the protostar grows in mass,
its surface gets brighter, while its core heats up. (d) When little gas
is left in the center of the dark core to strike the protostar, its
external growth and internal contraction slow significantly and the
object becomes a pre–main-sequence star. (Paul DiMare)
FIGURE 12-3 Dating the Pleiades (a) This open cluster called
the Pleiades can easily be seen with the naked eye in the
constellation Taurus (the Bull). It lies about 375 ly (116 pc) from
Earth. The stars are not shedding mass, unlike the star in Figure
12-14a. The blue glow surrounding the stars of the Pleiades is a
reflection nebula created as some of the stars’ radiation scatters
off preexisting dust grains in their vicinity. (b) Each dot plotted
on this H-R diagram represents a star in the Pleiades whose
luminosity and surface temperature have been determined. Note
that most of the cool, low-mass stars have arrived at the main
sequence, indicating that hydrogen fusion has begun in their
cores. The cluster has a diameter of about 5 ly, is about 100
million years old, and contains about 500 stars. (a: Anglo-
Australian Observatory)
FIGURE 13-4 Some Shapes of Planetary Nebulae
The outer shells of dying low-mass stars are ejected in
a wonderful variety of patterns. (a) NGC 7293, the
Helix Nebula, is located in the constellation Aquarius. The star
that ejected these gases is seen at the center of the glowing
shell. This nebula, located about 700 ly (215 pc) from Earth, has
an angular diameter equal to about half that of the full Moon.
(b) NGC 6826 shows jets of gas (in red) whose origin is as yet
unknown. (c) Mz 3 (Menzel 3), in the constellation Norma (the
Carpenter’s Level), is 3000 ly (900 pc) from Earth. The dying
star, creating these bubbles of gas, may be part of a binary
system. (a: NASA, NOAO, ESA, The Hubble Helix Nebula Team, M.
Meixner/STScI, and T. A. Rector/NRAO; b: Howard Bons, STScI/Robin
Ciardullo, Pennsylvania State University/NASA; c: AURA/STScI/NASA)
