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he Great Galaxy in Andromeda - Credit & Copyright: John P. Gleason, Celestial Images ASTRONOMY EDUCATION & OUTREACH
http://casswww.ucsd.edu/archive/public/astroed.html#TUTORIAL
University of California, San DiegoCenter for Astrophysics & Space Scienceshttp://casswww.ucsd.edu/archive/public/tutorial/scale.html
Space calendarhttp://www2.jpl.nasa.gov/calendar/
http://hubblesite.org/gallery/album/solar_system/
http://solarsystem.nasa.gov/index.cfm
http://solarsystem.nasa.gov/index.cfm
1-Overview of solar system: a- Planets. b-Space debris.
2- Origin of the solar system. a- Solar nebula theory. b- Extra-solar planets
Chapter 5. The Solar System.
Main points:
Sizes are to scale, but distances are not.
Chapter 5. The Solar System.
Main points:
Sizes are to scale, but distances are not.
If the sun were a large grapefruit (r~ 7 cm), the Earth would be a pinhead 15 meters away.
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Asteroid Belt
Solar System
Three types of planets: TERRESTRIAL JOVIAN AND DWARF .
Mercury
Venus
Earth
Mars
Moon
Jupiter
Saturn
Uranus
Neptune
Pluto
The Sun containsabout 99.8% of the mass of the Solar System
Terrestrial Planets.
Jovian Planets.
July 17, 2009: Forty two years ago, Apollo astronauts set out on a daring adventure to explore the Moon. They ended up discovering their own planet.
Planets revolve around the sun, counterclockwise as seen from the north pole, in the same direction and almost in the same plane.
Some general characteristics of the planets.
Mercury Venus Earth
Earth
Jupiter
Saturn
Neptune
Uranus
Pluto
Comet
Mercury’s orbit is tipped 7o and Pluto’s 17.2o off the plane of the ecliptic or plane of the solar system.
Inclination of planets to the plane of the ecliptic.
Terrestrial planets
Venus rotates backwards
Inclination of planets to the plane of the ecliptic.
Jovian planets
Uranus rotates on its side. •Sun’s axis is tipped 7o .
Saturn 27 0
Of the following OBJECTS, the orbit of _______, is the most inclined with respect to the plane of the solar system.
a- Venus b- Earth c- Mars
d- Jupiter e- Pluto
The Terrestrial planets are inside the orbit of the asteroid belt.
Terrestrial planets and their moons.
Counting from left to right Venus is the ______ object. a- first b- second c- third d- fourth
I am the planet _____ and the large scarf of about _____ km and _____ km deep, along the equator is called ________.My average surface temperature is only _______degrees.
I am the planet MARS and the large scarf of about 4 000 km and 200 km deep, along the equator is called Valles Marineris.My average surface temperature is only 210 K degrees.
Valles Marineris
Olympus Mon
Scientist believed that more than 4 billion years ago I had running water on my surface.
If that is the case what went wrong with me and where is the water?
Valles Marineris
Olympus Mon
Jupiter, Saturn, Uranus and Neptune.
JOVIAN PLANETS
Terrestrial Jovian
Comparing Terrestrial and Jovian planets
Radius
Earth has the largest radius r = 6 380 km.
Jupiter: 11 Earth’s radius.
Saturn: 9 “Uranus: 4 “Neptune: 4 “
orbital period
(years)
Mer. 0.24 Ven. 0.65Earth 1 Mars 1.88
Jupiter 11.86 Saturn 29.542Uranus 83.75Neptune 163.7
Orbital radius in AU
Mercury 0.39 Venus 0.7Earth 1 Mars 1.5
Jupiter: 5 Saturn: 10 Uranus: 19 Neptune: 30
Comparing Terrestrial and Jovian planets
Terrestrial Jovian
P2 = a3
solid, rich in metals: Fe, Al, Mg, Ni and silicates ( rocks).
Comparing Terrestrial and Jovian planets
Low concentration of low melting materials such us ices, water and gasses
Rich in gases , mostly hydrogen and helium.ices of water
Lots of ammonia (NH3), and methane (CH4).
Low concentrations of metals and silicates.
Similar in composition to the sun. (Solar in composition)
Low % in metals and silicates.
Terrestrial Jovian C
omp
osit
ion
Structure
Hot molten core of silicate and metals (rocky core)Rocky mantle.Thin crustsmall atmosphere.
Comparing Terrestrial and Jovian planets
Core: hot molten core of silicate and metals (rocky core)Not definedNot definedlarge atmosphere.
Terrestrial Jovian
Temperature From 273 to 750 K
Cold atmospheres : less than 100 K
Comparing Terrestrial and Jovian planets
Density = mass/volume
High 3.9 to 5.4 g/cm3
Low 0.7 to 1.7 g/cm3
Terrestrial Jovian
Surface with numerous impact crates.
No surface.
Jupiter is 316 times the mass of the Earth and Saturn’s is 96. The rest of the planets together only have 33 Earth masses.
September 5, 2011
Mercury observed by Messenger,
Sidereal Period of rotation
Mercury 58.64 days Venus 243.18 days Earth 23.93 hMars 24.62 h
Jupiter 9.9 hSaturn 10.7 hUranus 17.2 h Neptune 16.1 h
Comparing Terrestrial and Jovian planets
Terrestrial Jovian
Like the sun, the Jovian planets have differential rotation.
Slow rotation
Fast rotation
Slow rotation
Terrestrial Jovian
Ring No rings All have rings. The only rings visible from Earth are Saturn’s
Comparing Terrestrial and Jovian planets
Atmosphere Small or absent.Mercury lacks it.
Large
Jupiter and Saturn have large internal pressure that converts hydrogen gas to the liquid metallic state, which is a good conductor of electricity.
No boundary between liquid and gas.
Earth
Hot molten core
MetallicLiquid Hydrogen
JupiterSaturn
AtmosphereAtmosphere
Moons Few or no moons
Mars has two small and Earth one.
Mercury and Venus: no moons.
Many moons.
Some are larger than our moon.
Lots of smaller moons
Comparing Terrestrial and Jovian planets
Terrestrial Jovian
LargestThe Jovian planets have many moons. Some are bigger than our moon.
Moon Titan passing in front of Saturn
NASA/JPLCaltech/SSI
Jupiter has 4 Galilean Moon: Io. Europa, Callisto and Ganymede and 12 smaller moons.
Jovians
Uranus
Neptune
Jupiter Saturn
The Jovian planetsa- are similar in composition to the sun’s.b- are giant planets and thus, they have large densities.c- rotate very slowly.d- have cold cores, because they are far away from the sun.
a- are similar in composition to the sun’s.
The presence or absence of atmosphere in planets or asteroids is related to the escape speed and surface temperature.
Vo= 5 km/s Vo= 8 km/s Vo= 11.2 km/s
Escape speed.
What is escape speed?The initial speed an objects needs to escape from the surface of a planet, star, moon or asteroid is the……..
radius
massGVEscape
Celestial body Escape velocity (km/s)
Moon 2.0Mercury 4.0Mars 5.0Venus 10.0Earth 11.2Uranus 21.3Neptune 23.5Saturn 35.5Jupiter 60Sun 615White Dwarfs 6 000Neutron Stars 210 000 radius
massGVEscape
If the atoms and molecules of a gas move with an average speed similar to the escape speed , that gas is not present in the planet’s atmosphere.
Light molecules move faster than massive molecules, SO light molecules like hydrogen escape easily than the heavier ones, such as nitrogen or carbon monoxide.
The Moon and Mercury practically do not have any atmosphere, because their surfaces get too hot and because they have low escape speed.
Moon’s escape speed: 2 km/s Mercury’s escape speed: 4 km/s
Recall: atoms and molecules move fast at high temperature and slow at low temperature.
Therefore, a small planet (low escape speed) with high surface temperature does not have an atmosphere, buta small planet with low surface temperature might have an atmosphere.
Mercury and Titan have similar volumes.
Mercury is hot ( 500 K) and does not have any atmosphere
Titan cold is cold (100 K) and has and atmosphere
Jupiter’s escape speed:60 km/s ~ 5
Earth’s
The Jovian planets are cold and have a large escape speed therefore, they have large atmospheres.
North Magnetic pole
South Magnetic pole
Mag
neto
sphe
reThe stars and most planets have Magnetic Fields.
The stars’ and planets’ magnetic field is due to the Dynamo Effect.
Rotation +
Convection of a conducting medium
=Magnetic field.
The Earth, the Jovian planets, the sun and stars have magnetic fields.
Magneto-
sphere
Convection
zone.The sun rotates very fast and has a large convection zone, thus its magnetic field is intense.
Magnetosphere
The Earth’s magnetosphere is the region where the magnetic field is felt.
The “solar wind” consist of charged particles, protons and electrons escaping the sun’s upper atmosphere.
The charged particles from the sun interacts with the air molecules producing the aurorae borealis or australis.
Most of the particles in the solar wind are deflected by the Earth’s magnetosphere. A few particles spiral down to the northern and southern latitudes forming the “aurorae”
The charged particles in the solar wind interact with the air molecules producing the aurorae borealis or australis.
Name Distance Period (Y) Location from sun (AU)
Ceres 4.6 4.6 Asteroid belt Pluto 40 248 Kuiper beltHaumea 43 285 Kuiper beltMakemake 48 310 Kuiper beltEris 68 557 Kuiper belt
In 2006 the International Astronomical Union (IAU) created a new category of planets: Dwarf planets.
Dwarf planets.
Pluto.
1000 km
Eris
2 247 Km 3 330 km
Ceres
Three Dwarf Planet..
In the Asteroid belt
In the Kuiper belt
Pluto
ErisKuiper belt
Most of the dwarf planets are in the Kuiper belt, a cold region, beyond the orbit of Neptune.
Icy body:
Frozen water, gases and liquids such as: NH3 ammonia, CH4 methane, CO2 .
Rocky body:
A solid body rich in silicates, SiO2 and metals: Fe, Ni, Al, and Mg.
definitions:
Space Debris:
CometsMeteorites
Asteroids
Asteroids
Asteroids.Asteroids are the remains of the ‘planetesimals” that built the planets ~ 4.6 billion years ago!
1- Most in the asteroid belt,
with orbits between 1.8 AU and 3.3 AU.
2- The Trojan asteroids, share the orbit with Jupiter.
Where are the asteroids ?
Jupiter 5.2 AU
Mars 1.5 AU
Trojan
Tro
jan
The Apollo asteroids cross the Earth’s orbit.
Jupiter 5.2 AU
Many asteroids are in the Kuiper belt, beyond the orbit of Neptune
The asteroids, in the Kuiper belt, are large chunks of solid material, mainly icy, held by gravity.
C-type: carbonaceous, dark
S-type: silicate (rocky)
M-type: metallic; iron and nickel
Low density ~ 1.3 g/cm3 and are not made of solid hard rock.
There are basically Three types of Asteroids:
Asteroids observed by Galileo spacecraft in the asteroid belt.
Most asteroids, have irregular shapes, rotate on their axis and come in different sizes from large, to small (pebbles).
Ida rotating on its axis (HST).
The self-gravity of the asteroids is not enough to pull them into a spherical shape.
About 100 000 have been identified so far.
Vesta observed by Dawn spacecraft from a distance of about 3,200 miles (5,200 kilometers).on July 24, 2011.
Asteroid Vesta
Vesta ~ 600 km is the largest.
The spacecraft NEAR Shoemaker landed on the asteroid 433 Eros on February 2001.
These objects are a- rocks from the moon b- dwarf planetsc- asteroids d- meteorites
Some asteroids
a- have been discovered orbiting Jupiter
b- are similar in composition to Jupiter
c- have running water on their surface
d- have diameters of 2 000 miles.
e- none of the above.e- none of the above.
Bayeaux TapestryBayeaux TapestryNorman Invasion of Norman Invasion of 10661066
Comet of 1577Comet of 1577
B
C
Parts of a comet near the sun
A =
B=
C=
A
http://solarsystem.nasa.gov/index.cfm
Nucleus of comet Hartley 2 taken by NASA's EPOXI mission
Nucleus
Ices: water, carbon dioxide, ammonia methane and others.
Irregular fluffy (lots of voids) mixture of ices and pulverized rock (tiny particles).
Diameter of nucleus: from 10 to 50 km and a density of (0.1 to 0.25) g/cm3.
Rock: mainly pulverized silicates.nucleus of comet Hale, as seen by Giotto spacecraft.
Ion or gas TailDust T
ail
Tails
Comet West (1975))
The tails are produced by vaporizing ices and dust (rock) from the nucleus.
Ion or gas Tail
Comet West (1975)
Ion or gas tail consists of ionized gases. The CO+ ions scatters the blue light more efficiently than any other color and thus it looks blue
Dust Tail
The dust tail consist of tiny dusty particles. The dust reflects all the visible light from the sun and looks white.
Tails point away from the sun pushed by the solar wind and solar radiation pressure.
Tails are ~ 150 x106 km long.
A Neat Comet. Kitt Peak National Observatory (C/2001 Q4 z) Tenuous cloud of
evaporated gas, (CO2, H , water, ammonia, etc) and dust with a diameter of more than 100 000 km surrounding the nucleus.
Coma
Surrounding the coma is an invisible layer, or hydrogen envelope; the hydrogen may come from water molecules.
Coma
Orbit of Comet Kohoutek, 1973-1974.http://history.nasa.gov/SP-4208/p391.htm
The comets have long elliptical orbits, because they come from far away.
Ort Cloud
The Kuiper Belt.
Long period comets (more than 200 years of reappearance) come from the Oort cloud and short period- less than 200 years - comets come from the Kuiper belt.
Oort cloud
Sun
Planetary region
Sun
104 A
U5x10
5 A
UDimensions of the Oort cloud.
Inner radius 10 000 AU.
External radius 50 000 AU.
Comets from the Oort cloud, come in any direction from the sky,
No direct evidence of the Oort cloud!
The Kuiper belt: region of icy planetesimals. Pluto, Charon, Triton, Quaoar, Sedna, Eris, and more.
In the Oort cloud occasional passing stars may perturb the orbits.
In the Kuiper belt collision between them, or the gravitational force of Jupiter.
Why do comets leave their homes?
A solar system object, of rocky composition and comparable in size to a small city is most likely. a- a meteor b- cometc- an asteroid d- a planete- a meteoroid.
c- an asteroid
The nuclei of comets are fragile and lose lots of matter every time they come close to the sun leaving behind a trail of tiny particles.
Second Orbit
. ……
Hundredth Orbit
First Orbit
Third Orbit.
Short period comets and origin of meteors.
Meteoroid. Small solid particle moving towards earth’s atmosphere.
Meteor. Trail of light. “Shooting star’.
Meteorite. A particle that reaches earth’s surface. Many have been found.
Some definitions
Meteors and the meteor Meteors and the meteor showers are produced when showers are produced when the Earth enters the trail of the Earth enters the trail of
particles left behind by cometsparticles left behind by comets..
Meteor Showers.
Meteors are related to comets!
The meteors captured by Earth increase its mass 200 tons per day.
Meteor showers, seem to come from the same place in space.
The Leonid meteor shower, (November 14-19), seems to come from the Leonid constellation.
The 1833 storm
1997 Leonids from Orbit
After midnight the speed of the meteors and the rotation of the Earth's speed adds up improving the chance to see a meteor
Meteorites appear to be fragments of asteroids and even of terrestrial planets.
Iron-Ni, with ~ 7% Ni.
Meteorites endure the high temperature caused by air’s friction .
Particles that reach earth’s surface are the Meteorites.
Meteorites.
There are basically Three types of meteorites:
So: three types of asteroids.
M-type: metallic; iron and nickel
Fe
C-type: carbonaceous, dark
S-type: silicate (rocky)
Meteorite from the surface of Mars. It was hurled into space by and impact.
Which of the following is most likely related to comets?
a- asteroids
b- meteorites
c- meteors
d- dwarf planets
e- a & d.
c- meteors
Age of Solar SystemAge of Solar System..
- All objects in the solar system were formed around the same time.
- The age of the meteorites gives the age of the solar system. Radioactive dating,
Go to. http://lectureonline.cl.msu.edu/~mmp/applist/decay/decay.htm
Radioactive sample at t = 0 hours
Half life time - 10 hours.
In ten hours
The age of rocks is found comparing the original amount of radioactive (unstable) atoms and daughter abundance.
daughter
Parent Daughter Half life years
238U 206Pb 4.5 billion 40K 40Ca, 40Ar 1.3 billion226Rb 87Sr 47 billion
Half-life is the time in which half of the Half-life is the time in which half of the radioactive mass decays.radioactive mass decays.
Examples of half life.
Most of the oldest rocks found on Earth are only about 3.9 to 4.1 years old.
The meteorites and the rocks from the moon are about 4.6 billion years old. This is the age of the solar system.
The oldest rocks have been destroyed because the Earth is very active.
In 3 billionyears how many particles of Nonex have decayed?a. 150b. 220c. 1050d. 1000
Decay of “Nonex”
1200 - 150 = 1050
c. 1050
Meteors: come from comets they are fragile and easily burnt upon entering the atmosphere.
Meteorites: come from asteroids or planets. They are hard and make it to Earth.
Comets have highly elliptical orbits.
Asteroids are solid with rocky composition (carbon, silicates and metals).
Objects in the Kuiper belt are icy and very cold.
Summary:
The age of the solar system, about 4.9 billion years, is estimated from the age of the meteorites.
http://www.youtube.com/watch?v=Uhy1fucSRQI
See this video