Podcast
Questions and Answers
Our own galaxy is ______________ shaped.
Our own galaxy is ______________ shaped.
spiral
When did the solar system form?
When did the solar system form?
4.6-5 billion years ago
The process that drove the formation of the Sun is called __________________.
The process that drove the formation of the Sun is called __________________.
nuclear fusion
What is the temperature of the Sun?
What is the temperature of the Sun?
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Which of the following describes terrestrial planets?
Which of the following describes terrestrial planets?
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Which planets are classified as Jovian?
Which planets are classified as Jovian?
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Asteroids are solid ________________________ that independently orbit the Sun.
Asteroids are solid ________________________ that independently orbit the Sun.
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Comets are made of ices mixed with rocky or metallic solids and turn to gases when they approach the Sun, forming __________________.
Comets are made of ices mixed with rocky or metallic solids and turn to gases when they approach the Sun, forming __________________.
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Meteoroids are very small solid fragments that orbit the Sun and can cause a streak in the atmosphere known as a __________.
Meteoroids are very small solid fragments that orbit the Sun and can cause a streak in the atmosphere known as a __________.
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If a meteoroid reaches Earth's surface, it is called a __________.
If a meteoroid reaches Earth's surface, it is called a __________.
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A perfect circle has an eccentricity of 1.
A perfect circle has an eccentricity of 1.
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What is rotation?
What is rotation?
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What is revolution?
What is revolution?
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Study Notes
Our Milky Way Galaxy
- Our galaxy is spiral shaped and contains over 200 billion stars.
- Our solar system is located between two of the spiral arms and about ⅔ of the way from the center.
Our Solar System
- Our solar system is made up of the Sun and all of the objects that orbit around it.
- Most of our solar system is relatively empty.
Evolution of the Solar System
- Formed about 4.6-5 billion years ago.
- A large interstellar cloud of dust and gas collapsed due to gravity - Nebular Hypothesis.
Formation of the Sun at the Center
- Gravity led to the concentration of matter at the center.
- As heat and pressure increased, nuclear fusion drove the formation of the Sun.
- Material outside of the central mass of the Sun became the planets through collisions.
Parts of Our Solar System - The Sun
- Largest object in our solar system.
- Temperature = ~6,000 K.
- 70% Hydrogen, 28% Helium, 2% Metals.
- Nuclear fusion creates Sun’s energy.
Terrestrial Planets
- Inner Planets - closest to Sun.
- Rocky / Solid.
- Few Moons.
- Characteristics:
- High density.
- Small diameters.
Jovian Planets
- Outer Planets - farthest from Sun.
- Gaseous Planets - no solid surfaces.
- Many Moons.
- Characteristics:
- Low density.
- Large diameters.
Terrestrial vs. Jovian - Why???
- When the planets were forming, the Sun probably radiated more energy than it does today.
- High temperatures & pressure from particles emitted by the Sun drove the less dense elements away from the inner solar system.
- Outer parts not nearly as hot, and pressure not as great.
Parts of our Solar System - Asteroids
- ASTEROIDS - solid rocky and/or metallic bodies that independently orbit the Sun.
- Most of the known asteroids are in orbits between Mars and Jupiter (asteroid belt).
Parts of Our Solar System - Moons
- MOONS - bodies that orbit a planet or asteroid.
- Vary in size from a few km to larger than the smallest planets.
Parts of Our Solar System - Comets
- COMETS - Ices made of water or methane mixed with rocky or metallic solids.
- Ices turn to gases when they approach the Sun, Forming spectacular tails.
Parts of Our Solar System - Meteoroids
- METEOROIDS - very small solid fragments that orbit the Sun.
- As meteoroids enter our atmosphere, they burn up and leave a streak (Meteor).
- If the meteoroid reaches Earth’s surface it can create a depression (Meteorite – Impact crater).
Solar System Data - ESRT Pg. 15
Rotation
- Rotation - the spinning of a planet on its axis.
- 1 rotation = 1 day.
Revolution
- Revolution - the movement of a celestial object in an orbit around another celestial object.
- 1 orbit = 1 year for the planets in our solar system.
Kepler's Laws
- Kepler’s 1st Law of Planetary Motion: The orbits of the planets are ellipses with the Sun at one foci.
- Kepler's 2nd Law of Planetary Motion: An imaginary line drawn from the Sun to any planet sweeps out equal areas in equal times.
- Kepler’s 3rd Law of Planetary Motion: The square of the period of revolution of a planet is proportional to the cube of its average distance from the Sun.
Eccentricity
- Eccentricity - The degree of flattening or “ovalness” of an ellipse.
- Or, the amount of difference between an ellipse as compared to a circle.
- A perfect circle has an eccentricity of 0.
- A flat line has an eccentricity of 1.
- Therefore, eccentricity will always be a value between 0 and 1. (Pg. 1 ESRT)
- An increase in eccentricity makes the ellipse more flattened (more elliptical).
- A decrease in eccentricity makes the ellipse less flattened (more circular).
Factors Affecting Orbital Speed
- Mass of the Star: As the mass of the star increases, the orbital speed of the planet around it increases.
- Distance from the Star: As the distance from the star increases, the orbital speed of the planet decreases.
Orbital Eccentricity
- The orbital period of a planet is shorter for a more eccentric orbit.
- The orbital period of a planet is longer for a less eccentric orbit.
Steps For Making An Ellipse & Measuring Eccentricity
- Place two push pins in a piece of paper. These are the foci.
- Tie a string around the two thumbtacks.
- Place your pencil inside the string loop.
- Pull the string taut.
- Move the pencil around the foci, keeping the string tight.
- The resulting shape is an ellipse.
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Description
Explore the fascinating structure of our Milky Way galaxy and the solar system in this quiz. Learn about the formation of the sun, the evolution of our solar system, and the unique features of terrestrial planets. Test your knowledge on astronomical concepts and structures.
