The Solar System

Chapter 20 & 21

THE SOLAR SYSTEM

CHAPTER 21

The Sun: The Center of Our Solar The Sun: The Center of Our Solar SystemSystem

1. Main sequence star1. Main sequence star

2. Wider than 100 Earths2. Wider than 100 Earths

10,000 10,000 °F on surface & 27,000,000 °F in its core°F on surface & 27,000,000 °F in its core

less bright & massive than the very largest starsless bright & massive than the very largest starsAlthough its mass = Although its mass =

2,000,000,000,000,000,000,000,000,000 tons2,000,000,000,000,000,000,000,000,000 tons

This makes it more massive than 80% of all stars. This makes it more massive than 80% of all stars.

A truly "typical" star has a mass perhaps 1/4 of A truly "typical" star has a mass perhaps 1/4 of that of the Sun and is considerably less luminous that of the Sun and is considerably less luminous (bright). (bright).

Different Views of The Sun

3-D Image of the sun

UV Image of the sun

Normal Telescopic Image of the sun

Distances of the Inner Planets from the Sun in Astronomical Units

(150 million km = 1 AU)

The Inner Planets orThe Inner Planets or Terrestrial Planets Terrestrial Planets

1. Dense and Rocky1. Dense and Rocky2. Mercury2. Mercury3. Venus 3. Venus 4. Earth4. Earth5. Mars5. Mars

They are solids & close to the sun They are solids & close to the sun because the materials that make because the materials that make them can be a solid at high them can be a solid at high temperatures.temperatures.

The Inner PlanetsINNER PLANETS

MercuryMercury1. 1. 1/3 wide as Earth1/3 wide as Earth

2. 2. No moonsNo moons; resembles our moon because of all of its craters; resembles our moon because of all of its craters

3. Big, grey rock 3. Big, grey rock made of ironmade of iron

4. 24. 2ndnd hottest planet & smallesthottest planet & smallest

5. 5. Revolves around the sun in 88 daysRevolves around the sun in 88 days

6. 6. Rotates on its axis every 58 daysRotates on its axis every 58 days

1.5 days on Mercury = 88 days on Earth1.5 days on Mercury = 88 days on Earth

7. Temperature varies 7. Temperature varies -173-173°C to 427°C°C to 427°C since it since it lacks a lacks a protective atmosphere. protective atmosphere.

► Temperature variations on Mercury are the most extreme in Temperature variations on Mercury are the most extreme in the solar system. the solar system.

MercuryMercury

In Roman mythology Mercury is the god of commerce, travel and thievery, the Roman counterpart of the Greek god Hermes, the messenger of the Gods. The planet probably received this name because it moves so quickly across the sky.

Mercury has been known since at least the time of the Sumerians (3rd millennium BC). It was given two names by the Greeks: Apollo for its apparition as a morning star and Hermes as an evening star. Greek astronomers knew, however, that the two names referred to the same body. Heraclitus even believed that Mercury and Venus orbit the Sun, not the Earth.

http://www.nineplanets.org/mercury.html

VenusVenus1. 1. Earth’s twinEarth’s twin —its size is almost as big as Earth —its size is almost as big as Earth

2. 2. No moonsNo moons; ; thick yellow clouds of acidthick yellow clouds of acid

3. 3. Dense nickel & ironDense nickel & iron planet w/a molten core; planet w/a molten core; covered bycovered by many shield many shield volcanoes volcanoes (largest one is Sif (largest one is Sif Mons)Mons)

4. 4. Hottest planet in solar system at 464Hottest planet in solar system at 464°C due to its °C due to its thick atmospherethick atmosphere —exerts 90% times more pressure —exerts 90% times more pressure than the Earth’s atmosphere (would be like being than the Earth’s atmosphere (would be like being 1km deep in the ocean to stand on Venus)1km deep in the ocean to stand on Venus)

5. 5. Atmosphere made of carbon dioxideAtmosphere made of carbon dioxide (90%) (90%) & & sulfuric acidsulfuric acid, which creates a monstrous , which creates a monstrous greenhouse effect.greenhouse effect.

6. 6. Had waterHad water @ one point but it all @ one point but it all boiled away.boiled away.

VenusVenus

Venus (Greek: Aphrodite; Babylonian: Ishtar) is the goddess of love and beauty. The planet is so named probably because it is the brightest of the planets known to the ancients. (With a few exceptions, the surface features on Venus are named

for female figures.) Venus has been known since prehistoric times. It is the brightest object in the sky except for the Sun and the Moon. Like Mercury, it was popularly thought to be two separate bodies: Eosphorus as the morning star and Hesperus as the evening star, but the Greek astronomers knew better. (Venus's apparition as the morning

star is also sometimes called Lucifer.)

http://www.nineplanets.org/venus.html

EarthEarth

1. “Third rock from the sun,” made completely of rock; core made of iron & nickel; has magnetic field lines

2. 1 moon—Luna

3. Temperatures range from -13°C to 37°C

4. Densest planet in our solar system; has water in all 3 states of matter (solid, liquid,& gas)

5. 5th largest planet in solar system

EarthEarth

Earth is the only planet whose English name does not derive from Greek/Roman mythology. The name derives from Old English and Germanic.

In Roman Mythology, the goddess of the Earth was Tellus - the fertile soil (Greek: Gaia, terra mater - Mother Earth).

It was not until the time of Copernicus (the sixteenth century) that it was understood that the Earth is just another planet.

http://www.nineplanets.org/earth.html

Earth’s Moon: Earth’s Moon: Luna Luna (384,400 km from (384,400 km from Earth)Earth)

Called Luna by the Romans, Selene and Artemis by the Greeks, and many other names in other mythologies.

The Moon, of course, has been known since prehistoric times. It is the second brightest object in the sky after the Sun. As the Moon orbits around

the Earth once per month, the angle between the Earth, the Moon and the Sun changes; we see this as the cycle of the Moon's phases. The time between

successive new moons is 29.5 days (709 hours).

http://www.nineplanets.org/luna.html

MarsMars1. The 1. The red planetred planet — —red from rustred from rust, meaning that it , meaning that it had water had water

on iton it at one time at one time

2. Once had water on it; has polar ice caps that have both 2. Once had water on it; has polar ice caps that have both frozen water & carbon dioxide in themfrozen water & carbon dioxide in them

3. Many 3. Many scientists believescientists believe that most of Mars’ that most of Mars’ water lies frozen water lies frozen beneath Mars’ soilbeneath Mars’ soil

4. 4. Has 2 volcanoesHas 2 volcanoes —Tharsis (8,000 km wide) & Olympus Mons —Tharsis (8,000 km wide) & Olympus Mons—an extinct shield volcano—an extinct shield volcano

5. 5. Temperature ranges: -123Temperature ranges: -123°C°C to 37 to 37°C°C

6. 6. Revolution: 1 yr, 322 daysRevolution: 1 yr, 322 days

7. 7. 2 moons: Phobos & Deimos (mean fear & panic)2 moons: Phobos & Deimos (mean fear & panic)

PhobosPhobos

Phobos ("FOH bus") is the larger and innermost of Mars' two moons. Phobos is Greek for “fear.”Phobos is closer to its primary than any other moon in the solar system, less than 6000 km above the surface of Mars. It is also one of the smallest moons in the solar system.

http://www.nineplanets.org/phobos.html

DeimosDeimos

Deimos ("DEE mos") is the smaller and outermost of Mars' two moons. It is one of the smallest known moons in the solar system.

In Greek mythology, Deimos is one of the sons of Ares (Mars) and Aphrodite (Venus); "deimos" is Greek for "panic".

MarsMars

Mars (Greek: Ares) is the god of War. The planet probably got this name due to its red color; Mars is sometimes referred to as the Red Planet. (An interesting side note: the Roman god Mars was a god of agriculture before becoming associated with the Greek Ares; those in favor of colonizing and terraforming Mars may prefer this symbolism.) The name of the month March derives from Mars.

Mars—Home to the largest Mars—Home to the largest volcano in the solar systemvolcano in the solar system

Olympus Mons is the largest volcano on Mars. This shield volcano, similar to volcanoes in Hawaii, measures 624 km (374 mi) in diameter by 25 km (16 mi) high. It is 100 times larger than Mauna Loa on Earth. Located on the Tharsis Plateau near the equator, Olympus Mons is bordered by an escarpment. The caldera in the center is 80 km (50 mi) wide and contains multiple circular, overlapping collapse craters created by different volcanic events. The radial features on the slopes of the volcano were formed by overflowing lava and debris.

The Asteroid BeltThe Asteroid Belt1. 1. Small, rocky bodies that revolve around the sunSmall, rocky bodies that revolve around the sun

Made of leftovers from the formation of the universeMade of leftovers from the formation of the universe

2. Range in size from a 2. Range in size from a few meters to greater than few meters to greater than 900 km900 km in diameter in diameter

3. 3. Irregular shapesIrregular shapes, but larger ones are spherical, but larger ones are spherical

4. Most 4. Most orbit the sun in the asteroid beltorbit the sun in the asteroid belt — —a region a region of space b/w Mars & Jupiterof space b/w Mars & Jupiter

5. Asteroids 5. Asteroids vary in color depending on their vary in color depending on their locationlocation in the asteroid belt in the asteroid belt Outermost region = reddish brown to blackOutermost region = reddish brown to black (organic (organic

composition)composition) Innermost region = grayInnermost region = gray (carbon); light gray = (carbon); light gray =

stony/metallicstony/metallic

Famous AsteroidsFamous AsteroidsHektor

Ida and Dactyl

http://neo.jpl.nasa.gov/images/ida.html

Ceres: the largest of the Ceres: the largest of the asteroidsasteroids

Observations of 1 Ceres, the largest known asteroid, have revealed that the object may be a "mini planet," and may contain large amounts of pure water ice beneath its surface.

http://www.spaceflightnow.com/news/n0509/07ceres/

Meteoroids: “cousins” to Meteoroids: “cousins” to asteroids; shooting starsasteroids; shooting stars

1. Much smaller than asteroids1. Much smaller than asteroids

but very similarbut very similar

2. Meteoroids2. Meteoroids are small, rocky bodies are small, rocky bodies that revolve around the sun. that revolve around the sun.

3. Once it enters Earth’s atmosphere it 3. Once it enters Earth’s atmosphere it becomes a meteor & stays a meteor becomes a meteor & stays a meteor if it burns up in the atmosphere.if it burns up in the atmosphere.

4. If it strikes the ground it is a 4. If it strikes the ground it is a meteoritemeteorite..

Meteoroids continuedMeteoroids continued

1. 3 types:1. 3 types:

A. Stony—rocky materialA. Stony—rocky material

B. Metallic—iron & nickelB. Metallic—iron & nickel

C. Stony-iron—rocky, iron & nickelC. Stony-iron—rocky, iron & nickel

Rocky MeteoritesRocky Meteorites

http://meteorites.asu.edu/images/new-concord-big.jpg

Metallic MeteoritesMetallic Meteorites

http://www.astro.virginia.edu/class/oconnell/astr121/im/iron-meteorite.jpg

Stony-iron MeteoritesStony-iron Meteorites

http://www.gpc.edu/~pgore/myphotos/rocks/stonyironmeteor.jpg

Meteorite CraterMeteorite Crater

In Canyon Diablo in Arizona, USA, you can visit the best preserved meteorite crater on earth. It was formed about 22,000 years ago by the impact of a giant metallic nickel-iron meteorite, which arrived from space at a speed of about 50,000 kilometers per hour, and weighed many hundreds of tons. Friction with the atmosphere does not really slow such a mighty mass, which smashed into the solid earth, punching away 300 million tons of rock in a mighty blast which left a crater which even today is still 1.5 kilometers in diameter and 170 meters deep. (http://www.rocksonfire.com/About-Meteorites.htm)

The Outer PlanetsThe Outer Planets or or Gas Gas GiantsGiants

11. Jupiter. Jupiter22. Saturn. Saturn3. 3. UranusUranus4. 4. NeptuneNeptune5. 5. All are made of gasAll are made of gas. They are not solids . They are not solids

like the inner planets. like the inner planets. They get denser with increasing depth.They get denser with increasing depth.

6. 6. All have rings.All have rings.7. Since their masses are so much 7. Since their masses are so much

larger, they have more moons than larger, they have more moons than the inner planets.the inner planets.

Astronomical UnitsAstronomical Units –Outer Planets –Outer Planets(150 million km = 1 AU)(150 million km = 1 AU)

1. 1. JupiterJupiter 5.203 AU5.203 AU

2. Saturn2. Saturn 9.539 AU9.539 AU

3. Uranus3. Uranus 19.18 AU19.18 AU

4. 4. NeptuneNeptune

30.06 AU30.06 AU

JupiterJupiter1. The 1. The largest planetlargest planet in our solar system (318 times in our solar system (318 times

as large as Earth)as large as Earth) Its mass holds the asteroid belt in place & Its mass holds the asteroid belt in place &

protects Earth from asteroid assault.protects Earth from asteroid assault.

2. Made 2. Made mainly of hydrogen & heliummainly of hydrogen & helium

3. Cold planet; 3. Cold planet; average temperature = -110average temperature = -110°C°C

4. 4. Great Red SpotGreat Red Spot (1.5X the size of the Earth) is a (1.5X the size of the Earth) is a storm systemstorm system similar similar to a hurricane that is to a hurricane that is > 400 yrs old.> 400 yrs old.

5. 5. Rotation = 9 hrs, 54 minRotation = 9 hrs, 54 min

6. 6. Revolution = 11 yrs, 313 daysRevolution = 11 yrs, 313 days

Jupiter (continued)Jupiter (continued)8. Has 8. Has 63 moons63 moons as of Feb. 2004 as of Feb. 2004

9. 4 largest: 9. 4 largest: Io, Europa, Ganymede Io, Europa, Ganymede and Callisto and Callisto

10.10. Has rings like Saturn, but Has rings like Saturn, but much fainter & smallermuch fainter & smaller

Jupiter:Jupiter: http://www.nineplanets.org/jupiter.htmlhttp://www.nineplanets.org/jupiter.html

Roman god Jupiter (Greek Zeus) was the King of the Gods, the ruler of Olympus and the patron of the Roman state.

Jupiter is the fourth brightest object in the sky (after the Sun, the Moon and Venus). It has been known since prehistoric times as a bright "wandering star".

But in 1610 when Galileo first pointed a telescope at the sky he discovered Jupiter's four large moons and recorded their motions back and forth around

Jupiter.

Jupiter’s RingsJupiter’s Rings

1. Unlike Saturn's, Jupiter's rings are dark. 2. They're probably composed of very small grains of rocky

material. Unlike Saturn's rings, they seem to contain no ice.

SaturnSaturn1. 1. 22ndnd largest planet largest planet in the solar system (95 X larger than in the solar system (95 X larger than

Earth) Earth)

2. Composed mainly of 2. Composed mainly of hydrogen & heliumhydrogen & helium w/a small rocky w/a small rocky core.core.

3. 3. Average temperature = -140Average temperature = -140°C°C

4. Saturn’s 4. Saturn’s rings are the largestrings are the largest of the gas giants. of the gas giants.

5. 5. Made of icy particles Made of icy particles that range from a few cm to a few m that range from a few cm to a few m wide.wide.

6. 6. Revolution: 29 years, 155 daysRevolution: 29 years, 155 days

7. Rotation: 10 hrs, 42 min7. Rotation: 10 hrs, 42 min

8. 8. 31 moons31 moons

SaturnSaturn

In Roman mythology, Saturn is the god of agriculture. The associated Greek god, Cronus, was the son of Uranus and Gaia and the father of Zeus (Jupiter). Saturn is the root of the English word "Saturday“.

http://www.nineplanets.org/saturn.html

Saturn’s RingsSaturn’s Rings

http://www.nineplanets.org/saturn.html

1. Saturn’s rings are 250,000 km or more in diameter & they're less than one kilometer thick .

UranusUranus1. 1. Super cold -195Super cold -195°C°C

2. 2. 21 moons21 moons

3. 3. Revolution: 83 yrs, 273 daysRevolution: 83 yrs, 273 days

4. 4. Rotation: 17 hrs, 12 minRotation: 17 hrs, 12 min

5. 5. 11 rings11 rings

6. 6. 33rdrd largest largest planet planet

7. 7. Rotates on its side-Rotates on its side---planet was --planet was probablyprobably knocked on its side after knocked on its side after a a collision w/an asteroidcollision w/an asteroid– One side points toward the sun & the other in complete darkness for One side points toward the sun & the other in complete darkness for

part of the yearpart of the year

8. Made of 8. Made of hydrogen & methanehydrogen & methane —2 gases that absorb red light, —2 gases that absorb red light, givinggiving

Uranus its distinct blue/green colorUranus its distinct blue/green color

UranusUranus

Uranus is the ancient Greek deity of the Heavens, the earliest supreme god.

Uranus, the first planet discovered in modern times, was discovered by William Herschel while systematically searching the sky with his telescope on March 13, 1781. http://www.nineplanets.org/uranus.html

Uranus’ ringsUranus’ rings

http://hubblesite.org/newscenter/archive/releases/1996/15/image/a/format/web/

Neptune: Big Blue World Neptune: Big Blue World

1. 1. 11 moons11 moons

2. 2. Rotation: 16 hrs, 6 min.Rotation: 16 hrs, 6 min.

3. 3. Revolution: 163 yrs, 263 daysRevolution: 163 yrs, 263 days

4. 4. Temperature: -200 Temperature: -200 °C°C

5. 5. Has dark ringsHas dark rings

6. Neptune & Pluto’s orbits overlap causing 6. Neptune & Pluto’s orbits overlap causing Neptune to be further out than PlutoNeptune to be further out than Pluto

Neptune: Big Blue WorldNeptune: Big Blue World

1. Gets its 1. Gets its blue color fromblue color from being made being made of of methane gasmethane gas that absorbs red light, that absorbs red light, making Neptune appear bluemaking Neptune appear blue

2. Has 2. Has belts of clouds & a great Dark belts of clouds & a great Dark SpotSpot similar to Jupiter’s great Red Spot similar to Jupiter’s great Red Spot

3. 3. Tilted at a 30° angle so its poles are Tilted at a 30° angle so its poles are in light or dark for 40 yrs @ a time in light or dark for 40 yrs @ a time

NeptuneNeptune

In Roman mythology Neptune (Greek: Poseidon) was the god of the Sea.

The Great Dark Spot

http://www.nineplanets.org/neptune.html

Neptune’s Dark RingsNeptune’s Dark Rings

Kupier BeltKupier Belt (pronounced (pronounced kew p a)kew p a)

A region in space beyond Neptune where @ least 70,000 A region in space beyond Neptune where @ least 70,000 small, icy, slow-moving objects orbit the sunsmall, icy, slow-moving objects orbit the sun

A region where the planet-building process stopped before A region where the planet-building process stopped before any large objects where formedany large objects where formed

Pluto & is moon Charon (pronounced Sharon) are thought Pluto & is moon Charon (pronounced Sharon) are thought to be large members of itto be large members of it

Short-lived comets like Haley’s comet are also thought to Short-lived comets like Haley’s comet are also thought to come from the Kupier Beltcome from the Kupier Belt

Discovered in 1992 by Dutch-American astronomer Gerard Discovered in 1992 by Dutch-American astronomer Gerard P. KupierP. Kupier

Oort CloudOort Cloud

► A A large sphere that surrounds the solar systemlarge sphere that surrounds the solar system

► Where the Where the bulk of comets originatebulk of comets originate

► Suggested by astronomer Jan Oort in 1950Suggested by astronomer Jan Oort in 1950

► Both the Both the Kupier BeltKupier Belt & the & the Oort CloudOort Cloud are relatively are relatively pristine pristine remnants of the remnants of the nebulanebula from which the from which the entire solar system was formed.entire solar system was formed.

► Could contain as many as a trillion comets Could contain as many as a trillion comets

http://www.nineplanets.org/kboc.html

http://www.fas.org/irp/imint/docs/rst/Sect19/H_oort-cloud_02,0.jpg

CometsComets

http://www.nineplanets.org/comets.html

CometsComets Comets are sometimes called Comets are sometimes called dirty snowballsdirty snowballs or "icy mudballs". They are or "icy mudballs". They are

a mixture of ices (both water and frozen gases) and dust that for some a mixture of ices (both water and frozen gases) and dust that for some reason didn't get incorporated into planets when the solar system was reason didn't get incorporated into planets when the solar system was formed. This makes them very interesting as samples of the early history of formed. This makes them very interesting as samples of the early history of the solar system. the solar system.

When they are near the Sun and active, comets have several distinct parts: When they are near the Sun and active, comets have several distinct parts:

nucleusnucleus: relatively solid and stable, mostly ice and gas with a : relatively solid and stable, mostly ice and gas with a small small amount of dust and other solids; amount of dust and other solids;

comacoma: dense cloud of water, carbon dioxide and other neutral : dense cloud of water, carbon dioxide and other neutral gases gases sublimed from the nucleus; sublimed from the nucleus;

hydrogen cloudhydrogen cloud: huge (millions of km in diameter) but very : huge (millions of km in diameter) but very sparse sparse envelope of neutral hydrogen; envelope of neutral hydrogen;

dust taildust tail: up to 10 million km long composed of smoke-sized dust : up to 10 million km long composed of smoke-sized dust particles particles driven off the nucleus by escaping gases; this is driven off the nucleus by escaping gases; this is the most prominent the most prominent part of a comet to the unaided eye; part of a comet to the unaided eye;

ion tailion tail: as much as several hundred million km long composed of : as much as several hundred million km long composed of plasma and plasma and laced with rays and streamers caused by laced with rays and streamers caused by interactions with the solar interactions with the solar wind.wind.

http://www.nineplanets.org/comets.htmlhttp://www.nineplanets.org/comets.html

Sedna

• Large planetoid or asteroid

• More than 2X as far from the sun as Pluto

• Huge ball of ice, w/reddish color

• Revolves around the sun once every 10,500 yrs

• The coldest most distant place known in the solar system; possibly the first object in the long-hypothesized Oort cloud

90 AU

Sedna—what we think it looks like

Sedna's physical composition is a bit of a mystery. You would expect it to be mostly ices but apparently that's not the case. About all that's known at this

time is that it is very red and that water and methane ices seem to be absent on the surface.

Sedna is definitely not the "Planet X" that many astronomers anticipated before the discovery of Pluto. Planet X was supposed to be a much larger

object. http://www.nineplanets.org/sedna.html

Eris—the next “dwarf planet”

• Officially named in 9/2006• Named for the goddess of chaos & strife• 1 moon = Dysomia: Spirit of lawlessness• Eris, the largest dwarf planet known

• The dwarf planet is the most distant object ever seen in orbit around the sun, even more distant than Sedna, the planetoid discovered almost 2 years ago. It is almost 10 billion miles from the sun and more than 3 times more distant than the next closest planet, Pluto and takes more than twice as long to orbit the sun as Pluto.

Xena

• Another planetoid that will probably become another “dwarf planet” in the coming months

• It's the largest nonstellar object now known to exist beyond the orbit of Neptune. And, at roughly 97 AU, or Astronomical Units (one AU equals the Earth's distance from the Sun, about 93 million miles) it's also the most distant.