Space and AstronomyStudy GuideStandard 1Earth Science

What things move around in the What things move around in the night sky and why?night sky and why? • Moons, comets, asteroids, planets; Moons, comets, asteroids, planets;

because they are closer than the starsbecause they are closer than the stars

Explain how we know objects inExplain how we know objects inthe sky are so far away.the sky are so far away.

• Because they move less. (Parallax – Because they move less. (Parallax – remember your car)remember your car)

• Because they appear smaller (think Because they appear smaller (think head squishing)head squishing)

What does gravity do?What does gravity do? • It pulls all matter in the universe It pulls all matter in the universe

together. together.

• Depends on mass and distance.Depends on mass and distance.

What is a nebula?What is a nebula? • A cloud of dust and gas. A cloud of dust and gas.

• Forms solar systems and stars.Forms solar systems and stars.

What are the stages of the What are the stages of the formation of our Solar System?formation of our Solar System?

1.1. NebulaNebula

2.2. Gravitational CollapseGravitational Collapse

3.3. SpinningSpinning

4.4. Flattening to Disk Flattening to Disk

5.5. FusionFusion

6.6. Accretion of PlanetsAccretion of Planets

What kinds of objects are in our What kinds of objects are in our solar system?solar system?

• The Sun The Sun

• 8 Planets8 Planets

• 3+ Dwarf Planets3+ Dwarf Planets

• 240+ Moons240+ Moons

• Small Bodies (Comets, Asteroids, Gas, Small Bodies (Comets, Asteroids, Gas, Dust)Dust)

How are stars formed?How are stars formed?

1.1. NebulaNebula

2.2. Gravitational CollapseGravitational Collapse

3.3. FusionFusion

What two gases are present in our Sun, and most stars? • Hydrogen and helium.

• In the Sun 75% hydrogen and 25%. Helium.

Explain what fusion is.

• When small elements join (fuse) to make larger elements.

• The most common kind is hydrogen combining to make helium.

How are planets formed? • By condensation of cooling pieces of

gas and dust around the sun.

1. Spinning

2. Flattening to Disk

3. Accretion of Planets

Name 6 differences between inner Name 6 differences between inner and outer planets.and outer planets.

1.1. Size Size

2.2. Density Density

3.3. Atmosphere (Thick & Light, Thin & Heavy)Atmosphere (Thick & Light, Thin & Heavy)

4.4. Distance from Sun & SpacingDistance from Sun & Spacing

5.5. Compostion (Gas vs. Rock & Metal)Compostion (Gas vs. Rock & Metal)

6.6. Number of MoonsNumber of Moons

Bonus: Rotation SpeedBonus: Rotation Speed

Explain why the inner planets are so different from the outer planets. • The solar wind blows light material

farther out while gravity keeps the heavier material close.

• As a result the inner planets are heavy and the outer planets are light.

• There is more light material so the light planets are bigger.

Explain how old the Solar system is and how we know this. • At least 4.6 billion years old

• This is the age of the oldest rocks and meteors determined with radioisotope dating.

Why are there more crater impacts Why are there more crater impacts on the moon than on the earth?on the moon than on the earth? • The Earth has an atmosphere and plate The Earth has an atmosphere and plate

tectonics that weathers away craters.tectonics that weathers away craters.

• The moon is dead and has no erosion.The moon is dead and has no erosion.

What causes the seasons on earth?• The seasons are caused by the earth’s

tilt.

What is the Earth’s rotation?What is the Earth’s rotation?

• It is the time it takes for earth to turn It is the time it takes for earth to turn one time on its axis.one time on its axis.

• One day. ~23.93 hours.One day. ~23.93 hours.

What is the Earth’s Revolution What is the Earth’s Revolution around the sun?around the sun? • The time it takes for Earth to make one The time it takes for Earth to make one

orbit around the sun.orbit around the sun.

• One year. 365.26 daysOne year. 365.26 days