Transcript Solar.System

The Solar System
• 1 star
• 9 8 planets
• 63 (major) moons
• asteroids, comets, meteoroids
The Sun
• The sun’s energy comes from
nuclear fusion (where hydrogen is
converted to helium) within its
core. This energy is released from
the sun in the form of heat and
light.
• Remember: Stars produce light.
Planets reflect light.
• A star’s temperature determines its
“color.” The coldest stars are red.
The hottest stars are blue.
The Planets of the Solar System
• Planets are categorized according to
composition and size. There are two main
categories of planets:
– Terrestrial small rocky planets (Mercury,
Venus, Earth, Mars)
– Jovian gas giants (Jupiter, Saturn, Uranus,
and Neptune)
Characteristics of Small Rocky
Planets
•
•
•
•
•
They are made up mostly of rock and metal.
They are very heavy.
They move slowly in space.
They have no rings and few moons (if any).
They have a diameter of less than 13,000
km.
Mercury
• Mercury has a revolution
period of 88 days. Mercury
has extreme temperature
fluctuations, ranging from
800F (daytime) to -270F
(nighttime).
• Even though it is the closest
planet to the sun, Scientists
believe there is ICE on
Mercury! The ice is
protected from the sun’s heat
by crater shadows.
Venus
• Venus is the brightest object
in the sky after the sun and
moon because its atmosphere
reflects sunlight so well.
People often mistake it for a
star.
• Its maximum surface
temperature may reach 900F.
• Venus has no moons and
takes 225 days to complete an
orbit.
Earth
• Earth is the only planet
known to support living
organisms.
• Earth’s surface is composed
of 71% water.
– Water is necessary for life on
Earth.
– The oceans help maintain
Earth’s stable temperatures.
• Earth has one moon and an
oxygen rich atmosphere.
Earth’s Moon
• It takes the moon approximately 29 days to
complete one rotation. The same side of the moon
always faces us.
• The moon’s surface is covered in dust and rocky
debris from meteor impacts. It has no water or
atmosphere.
• The moon reflects light from the sun onto the earth’s
surface.
Mars
• Like Earth, Mars has ice caps
at its poles.
• Mars has the largest volcano
in our solar system: Olympus
Mons. Olympus Mons is
approximately 15 miles high.
• Mars appears red because of
iron oxide, or rust, in its soil.
• Mars has two moons and
takes about two years to
complete an orbit.
Moons of Mars
Phobos
Deimos
Gouged by a giant impact
crater and beaten by thousands
of meteorite impacts, Phobos is
on a collision course with Mars.
It may collide with Mars in 50
million years or break up into a
ring.
It is also heavily
cratered with a small
lumpy appearance.
Pluto
• Pluto has only 5 moons and
takes about 249 years to
orbit the sun.
• Part of Pluto’s orbit passes
inside that of Neptune, so at
times Neptune is the planet
farthest from the sun.
• Pluto was located and
named in 1930, but today
Pluto is no longer
considered a
planet.
Largest is Charon
Characteristics of Gas Giants
• They are made up mostly of gases
(primarily hydrogen & helium).
• They are very light for their size.
• They move quickly in space.
• They have rings and many moons.
• They have a diameter of less than 48,000
km
Jupiter
• Jupiter is the largest and
most massive planet.
• It’s diameter is 11 times
bigger than that of the
Earth’s.
• It takes about 12 years for
Jupiter to orbit the sun.
• Jupiter has 63 known
moons.
Moons of Jupiter
1. Io
2. Europa
3. Ganymede
4. Callisto
5. Amalthea
6. Himalia
7. Elara
8. Pasiphae
9. Sinope
10. Lysithea
11. Carme
12. Ananke
13. Leda
14. Thebe
15. Adrastea
16. Metis
17. Callirrhoe
18. Themisto
19. Megaclite
20. Taygete
21. Chaldene
22. Harpalyke
23. Kalyke
24. Iocaste
25. Erinome
26. Isonoe
27. Praxidike
28. Autonoe
29. Thyone
30. Hermippe
31. Aitne
32. Eurydome
33. Euanthe
34. Euporie
35. Orthosie
36. Sponde
37. Kale
38. Pasithee
39. Hegemone
40. Mneme
41. Aoede
42. Thelxinoe
43. Arche
44. Kallichore
45. Helike
46. Carpo
47. Eukelade
48. Cyllene
49. Kore
50. S/2003 J2
51. S/2003 J3
52. S/2003 J4
53. S/2000 J11
54. S/2000 J5
55. S/2003 J9
56. S/2003 J10
57. S/2003 J12
58. S/2003 J15
59. S/2003 J16
60. S/2003 J17
61. S/2003 J18
62. S/2003 J19
63. S/2003 J23
Saturn
• Saturn is composed almost
entirely of hydrogen and
helium.
• Saturn has many rings made
of ice. Saturn’s rings are
very wide. They extend
outward to about 260,000
miles from the surface but
are less than 1 mile thick.
• Saturn has 60 known moons,
some of which orbit inside
the rings!
• It takes Saturn about 30
years to orbit the sun.
Moons of Saturn
1. Mimas
2. Enceladus
3. Tethys
4. Dione
5. Rhea
6. Titan
7. Hyperion
8. Iapetus
9. Erriapus
10. Phoebe
11. Janus
12. Epimetheus
13. Helene
14. Telesto
15. Calypso
16. Kiviuq
17. Atlas
18.
Prometheus
19. Pandora
20. Pan
21. Ymir
22. Paaliaq
23. Tarvos
24. Ijiraq
25. Suttungr
26. Mundilfari
27. Albiorix
28. Skathi
29. Siarnaq
30. Thrymr
31. Narvi
32. Methone
33. Pallene
34. Polydeuces
35. Daphnis
36. Aegir
37. Bebhionn
38. Bergelmir
39. Bestla
40. Farbauti
41. Fenrir
42. Fornjot
43. Hati
44. Hyrokkin
45. Kari
46. Loge
47. Skoll
48. Surtur
49. S/2004 S7
50. S/2004 S12
51. S/2004 S13
52. S/2004 S17
53. S/2006 S1
54. S/2006 S3
55. Greip
56. Jarnsaxa
57. Tarqeq
58. S/2007 S2
59. S/2007 S3
60. Anthe
Uranus
• Uranus is blue in
color due to methane
gas in its atmosphere.
• Uranus has 11 dark
rings surrounding it.
• Uranus has 27 known
moons and takes 84
years to complete one
orbit.
Moons of Uranus
1. Cordelia
2. Ophelia
3. Bianca
4. Cressida
5. Desdemona
6. Juliet
7. Portia
8. Rosalind
9. Mab
10. Belinda
11. Perdita
12. Puck
13. Cupid
14. Miranda
15. Francisco
16. Ariel
17. Umbriel
18. Titania
19. Oberon
20. Caliban
21. Stephano
22. Trinculo
23. Sycorax
24. Margaret
25. Prospero
26. Setebos
27. Ferdinand
BACK
| The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet)
| Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |
Neptune
• Neptune has the fastest
winds in the solar
system: up to 2,000
km/hr.
• Neptune is also blue in
color due to methane gas
in its atmosphere.
• Neptune takes 165 years
to orbit the sun and has
13 moons.
Planets song
Moons of Neptune
1. Triton
2. Nereid
3. Naiad
4. Thalassa
5. Despina
6. Galatea
7. Larissa
8. Proteus
9. Halimede
10. Psamathe
11. Sao
12. Laomedeia
13. Neso
BACK
| The Solar System | Sun | Mercury | Venus | Earth | Mars | Jupiter | Saturn | Uranus | Neptune | Pluto (Dwarf Planet)
| Asteroids | Comets | Meteors, Meteoroids, and Meteorites | End Show |
Terrestrial Planets
•Mercury, Venus, Earth
and Mars
•Close to Sun
•Small masses, radii
•Rocky, solid surfaces
•High densities
•Slow rotation
•Weak magnetic field
•No rings
•Few moons
Jovian Planets
•Jupiter, Saturn,
Uranus, and Neptune
•Far from Sun
•Large masses and radii
•Gaseous surface
•Low densities
•Fast rotation
•Strong magnetic field
•Many rings
•Many moons
The distances to planets are known from Kepler’s Laws
(once calibrated with radar ranging to Venus)
How are planet sizes determined?
Measure angular size on sky,
Then use geometry…..
Using angular size to
get actual size
Masses - determined through observing the gravitational effect of the
planet on some nearby object (moons, nearby planets, satellites)
Density - divide mass by volume
• Planets orbit the
sun counterclockwise as seen
from the North
Celestial Pole.
• All planets are in
the same orbital
plane EXCEPT
Mercury and
Pluto.
Terrestrial planets
Jovian planets (and earth)
OTHER SOLAR SYSTEM
OBJECTS
Kuiper Belt Objects
• These large, icy
objects have orbits
similar to the
smaller objects in
the Kuiper belt
that become short
period comets.
• So are they very
large comets or
very small
planets?
Hubble’s View of Pluto and Its
Moons
Other Kuiper Belt Objects
• Most have been discovered very recently
so little is known about them.
• NASA’s New Horizons mission will study
Pluto and a few other Kuiper belt object in
a planned flyby.
Are Pluto and Eris planets?
Pluto and Eris
• Pluto’s size was overestimated after its
discovery in 1930, and nothing of similar size
was discovered for several decades.
• Now other large objects have been discovered
in Kuiper belt, including Eris.
• The International Astronomical Union (IAU) now
classifies Pluto and Eris as dwarf planets.
• Dwarf planets have not cleared most other
objects from their orbital paths.
Asteroids - rocks with sizes greater than 100m across
Most asteroids remain in the Asteroid belt between
Mars and Jupiter but a few have orbits that cross
Earth’s path.
Three asteroids
hit the Earth
every 1 million
years!
Known asteroid impact sites
Asteroid sizes range from 100m to about 1000km
They are composed of carbon
or iron and other rocky
material.
The Asteroid belt is a group of
rocks that appear to have never
joined to make a planet. Why do
we think this?
•Too little mass to be a planet
•Asteriods have different chemical
compositions
It’s all Jupiter’s fault…..
Meteoroids –
interplanetary rocky
material smaller than 100m
(down to grain size).
•called a meteor as it burns
in the Earth’s atmosphere
•if it makes it to the ground,
it is a meteorite
Most meteor showers are
the result of the Earth
passing through the orbit of
a comet which has left
debris along its path
Meteors are rocky - mainly iron and nickel
Some contain carbonaceous material - rich in organic material
Meteors are old - 4.5 billion years - based on carbon dating
Meteor crater near
Winslow, AZ - the
culprit was
probably 50 m
across weighing
200,000 tons!
Meteor showers:
Orionid – Oct 21/22
Leonid – Nov 18/19
Geminid – Dec 14/15
Comets
Dirty snowballs - dust and rock in methane, ammonia and ice
All light is reflected from the Sun - the comet makes no light of its own
Halley’s Comet in 1986
The nucleus is a few km in diameter
•Cometary orbits take them far beyond Pluto
•Many take up to 1 million years to orbit the Sun once!
•These long period comets probably originate in the Oort cloud
•Short period comets (< 200 years) (like Halley’s comet)
•Short period comets may have originated in the Kuiper belt
•Kuiper belt comet gets “kicked” into an eccentric orbit, bringing
it into the solar system
Formation of the Solar System
Any theory to describe the formation of our Solar System
must adhere to these facts:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Each planet is isolated in space
The orbits are nearly circular
The orbits of the planets all lie in roughly the same plane
The direction they orbit around the Sun is the same as the
Sun’s rotation on its axis
The direction most planets rotate on their axes is the same as
that for the Sun
The direction of a planet’s moon orbits is the same as that
planet’s direction of rotation
The Terrestrial planets are very different from the Jovian
planets
Asteroids are different from both types of planets
Comets are icy fragments that don’t orbit in the ecliptic plane
Nebular Theory for Solar System formation
Our sun and the planets began from a cloud of dust and gas (nebula)
As the cloud contracts under its own
gravity, the Sun is formed at the
center.
The cloud starts to spin and the
smaller it contracts, the faster it spins.
Conservation of angular momentum
Cloud forms a flattened, pancake shape.
We’ve seen these disks around other young stars!
Beta Pictoris
Conservation of Angular Momentum
Angular momentum
 mass  rotation rate
 radius2
Condensation Theory for Planet Formation
The gas in the flattened nebula would never eventually
clump together to form planets.
Interstellar dust (grain-size particles) lies between stars remnants of old, dead stars.
These dust grains form
condensation nuclei other atoms attach to
them to start the
“collapsing” process to
form the planets in the
gas cloud.
What happened next…..
A flattened solar nebula disk exists
after cloud spins and contracts
Condensation nuclei form clumps
that grow into moon-size
planetesimals
Solar wind from star formation (Sun
forming) blow out the rest of the gas
Planetesimals collide and grow
Planetesimals form the basic planets
over hundred million years
Why the difference between inner and outer planets?
TEMPERATURE!
•Rocky inner planets: The
type of the material that
condensed out of the nebular
cloud at these higher
temperatures was rocky in
nature.
•Gaseous, Bigger outer
planets: Both rock and gas
could condense out of the
cloud at lower temperatures
where these planets formed.
Why are they gaseous? - gas is present
Why are they bigger? - accretion onto the planet starts sooner
because they are further from the Sun, less effected by solar wind