Chapter 5 part one.

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


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


Terrestrial Jovian

P2 = a3

solid, rich in metals: Fe, Al, Mg, Ni and silicates ( rocks).


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.


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


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


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


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


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


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

Chapter 5 part one.

Documents

terrestrial jovian planets

inclination of planets

terrestrial planetsvenus

plane ofthe solar system

overview of solar system

jovian planetsjupiter

jovian planetsuranus

large mercury