U4D1-Astronomical Bodies Power Point (new)

U4D1: Astronomical Bodies of the Universe

Objective

• Students will distinguish the hierarchical relationships between planets and other astronomical bodies relative to:

  • Solar system

  • Galaxy

  • Universe

  • Includes distance, size, and composition

Essential Questions

1. How does the relative distance, relative size, and general composition of astronomical bodies in the universe differ?

2. How are the distances between objects in space in the context of light and space travel?

3. How many galaxies and stars are contained in the universe?

Agenda

• Essential Questions

• Bell Ringer

• PowerPoint

• Guided Notes

• Exit Ticket

Bell Ringer

• Scenario: Jill is creating a scale model of the Solar System using a basketball to represent the Sun.

• Question: Which of the following should she use to accurately represent the size of Earth?

  • A. Tennis ball

  • B. Ping pong ball

  • C. Marble

  • D. Grain of sand

What is Astronomy?

• Astronomy is the science aimed at observing and understanding celestial bodies, including their:

  • Position

  • Movement

  • Structure

  • Evolution

Travel Times in Space

• Time for light to travel from the Sun to Earth: 8.5 minutes

• Time for a bullet shot towards the sun from just outside Earth's atmosphere: 30 years

Measuring Sizes and Distances in the Universe

Astronomical Units (AU)

• Measuring distances in the solar system:

  • 1 AU = average distance between Earth and the Sun (approx. 150 million km / 93 million miles)

  • Pluto averages about 40 AU from the Sun

  • Not large enough for measuring distances outside the solar system

Light Year

• Distance light travels in one year

• Light speed: 300,000 km per second

• One light-year ≈ 9.5 trillion km

Relative Distances and Sizes

List of Astronomical Bodies (From Bigger to Smaller)

• Galaxy

• Nebulae

• Star

• Planet

• Moon

• Asteroid

• Comet

• Meteorite

Meteorites

• Solid piece of rock that survives the fall to Earth’s surface

• Usually originates from a comet or asteroid

Comets

• Composed of dust, water ice, and frozen gas

• Larger than meteorites but smaller than asteroids

• Characterized by tails due to solar radiation or solar wind

Asteroids

• Also known as minor planets

• Most located within the asteroid belt

• Mainly composed of metal

Size Comparison

• General Size Order: Asteroids (largest) > Comets > Meteorites

Moons

• Natural satellites, often solid bodies

• Few have atmospheres, primarily formed from gas and dust discs circling planets

• Terrestrial Planet Moons:

  • Mercury & Venus: None

  • Earth: 1

  • Mars: 2

• Gas Giant Moons: Jupiter, Saturn, Uranus, Neptune: Numerous moons

Difference Between Moons and Asteroids

• Moons orbit planets

• Asteroids orbit the Sun

Planets

• Rounded by their own gravity

• Revolve around the Sun

• Divided into:

  • Inner (High Density) Terrestrial Planets

  • Outer (Low Density) Gas Giants

Stars

• Massive bright balls of plasma held together by gravity

• The Sun: Earth’s primary energy source

Nebulae

• Interstellar clouds of dust and gases

• Key in star formation by clumping materials together to form larger masses, leading to star birth and planet formation.

Galaxies

• Three types:

  • Elliptical (older)

  • Spiral (younger)

  • Irregular

• Contain hundreds of billions of stars

Universe

• Encompasses all matter, energy, and existence

• Age: 13.7 billion years

• Current star count estimate: ~10²¹ stars

Understanding the Vastness of the Universe

• Solar System: Distance scale from the Sun to planets, e.g., Mercury = 1 step, Venus = 2 steps, Earth = 2.5 steps, etc.

Exit Ticket Questions

Example Questions

1. Which statement about relative astronomical size is correct?

2. Between which of the following would Astronomical Units be appropriate for distance measurement?

3. Primary difference between a moon and planet?

4. True statement regarding measuring distances in space?

5. Common characteristic shared by inner and outer planets?