Semester II Final Review

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

Mercury is only Slightly Larger Mercury is only Slightly Larger than the Moonthan the Moon

MERCURY

OUR MOON

Mercury’s iron core takes up a much larger Mercury’s iron core takes up a much larger percentage its volume than that of Earth.percentage its volume than that of Earth.

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

The extreme heating of Venus’ surface is The 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!

Mars Notes

II. Surface Geologya. 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??

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.

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

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.

Mars Notes

III. Atmosphere

a. 1/100 Earth’s pressure

b. Thin CO2

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

Layers of rock laid down by Layers of rock laid down by waterwater

Hemetite black rocks, usually formed in water

Gullies in crater walls

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.

The two moons of Mars, Deimos and Phobos, The two moons of Mars, Deimos and Phobos, are small and non-spherical in shape. These are small and non-spherical in shape. These are planetesimals captured by Mars.are planetesimals captured by Mars.

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.

Jupiter’s clouds move in east-west bandsJupiter’s clouds move in east-west bands

Reddish-colored belts alternate with white-colored zones.

What is it??

Compare and contrast Jupiter and Saturn.

Notes

III. Ring Kinga. 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)

What is happening in this picture????

Where is Uranus?

Uranus Notes

I. Facts

a. First planet discovered by telescope

b. 1781, William Herschel

c. Doing telescopic study of sky, he noticed something new!!

Uranus and Neptune Uranus and Neptune are Comparable in Sizeare Comparable in Size

URANUSURANUS NEPTUNENEPTUNE

EARTH ON EARTH ON THE SAME THE SAME SCALESCALE

The interiors of Uranus and Neptune are both believed to have the same layers.

What is happening??

Neptune notes

II. Compositiona. Liquid H and He surface

b. Methane gives blue color

c. Highly compressed water below surface

d. Rocky Core

What is it???

Can you find Pluto?

Comet Notes

I. HISTORY:

a. Latin – “long hair”

b. Originally omens of misfortune!

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

Many Objects Exist Far Out in the Many 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.

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.

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!

STRUCTURE OF A STRUCTURE OF A COMETCOMET

Meteor Notes

• Meteoroids – Pieces of rock debris in the solar system.– May be remnants of comets or asteroids.

Meteoroids pulled into our atmosphere by Earth’s gravity heat the surrounding gases, causing them to glow.

Thus, they become meteors.

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

During certain predictable times, Earth passes through sections of its orbit containing debris from a comet, resulting in a meteor shower.

Notes

• Meteorites – Rock debris hitting Earth. Most likely asteroids or Mars fragments. – 300 tons per day!– Pitted Fe or Ni rocks from atmospheric friction

Recent Impact Sites Recent 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.

Willamette meteorite, 14.1 ton , New York.

Antarctic Meteorite Newsletter

Trees flattened over an area 30km in diameter by the Trees flattened over an area 30km in diameter by the Tunguska Impact in 1908Tunguska Impact in 1908

The crater was created about 50,000 years ago

Confirming an Extinction-Confirming an Extinction-Level Impact SiteLevel Impact Site

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)

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

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.

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.

Notes

II. Fusion

a. At 10 million K, fusion begins.

b. If enough mass for a chain reaction, a star is born (CRITICAL MASS)

The Pleiades

The blue glow surrounding the stars of the Pleiades is areflection 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.

“Oh, Be A Fine Guy/Girl, Kiss Me!”

Spectral Classes

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.

Planetary NebulaeShapes 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

Nucleosynthesis

I. Basics:

a. Only H formed out of the big bang!

Nucleosynthesis

b. He (2 protons) through Fe (26 protons) form inside stars through a sequence of fusing protons.

Nucleosythesis

c. Elements heavier (more protons) than iron form in a super nova explosion (exploding star)

Name the layers of the Sun, starting at the middle.

What is shown

here? Label the

parts.

Describe the relationship between sunspots, solar flares, and prominences.

Describe the cause of the Auroras. Be specific.

What is being shown in this picture?

Be as specific as possible.

Notes

II. Vocab

1. Galactic nucleus – With super massive black hole of 4 million solar masses.

NotesII Vocab

2. Spherical Halo – consisting of old globular clusters, planetary nebula and old stars.

Notes

II. Vocab

c. Spiral Arms – mostly gas, dust, and young stars

Notes

III. Vocab

4. Globular Clusters

1. 1,000 – 100,000 old stars (red).

2. Spherical due to combined gravity. 3. Found around galactic center.

Notes

III Vocab

5. Open Star Cluster –

- 10s to 1000s of young stars

- 3 – 30 LY across

Notes

III Vocab

6. Pulsar – rotating neutron star.

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

Galaxy Notes

II. Spiral Galaxies

Disk and arms with central bulge

Sa – arms tight to center

Sb – arms midway

Sc – arms open wide

Galaxy Notes

III. Barred Galaxy (SB)

Bulge in middle is bar shape

Arms open quickly

IV. Irregular galaxy

No shape

LMC and SMC