AstronomyLesson 1 of 4 in the course Other Worlds: An Introduction to the Solar System

Solar System Structure, Small Bodies, Scale, and Classification

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

The solar system is a family of objects held together by the gravity of the Sun. This lesson introduces its members, how they formed, and how astronomers investigate them.

A planetary system is a star and the planets and other objects that orbit it. Our planetary system is called the solar system because the Sun is sometimes called Sol. In strict usage, planets orbiting other stars belong to other planetary systems.

All flashcards

Revolution period
The time a body takes to complete one orbit around the Sun.
Average density
An object's mass divided by its volume; it can provide clues about composition.
Solar-system formation
Most members formed together about 4.5 billion years ago from a cloud of gas and dust.
Scale factor
The ratio by which a model's sizes and distances are reduced from reality.
Carl Sagan's contributions
He advanced planetary science, supported robotic exploration, and communicated astronomy to the public.

Quiz questions

  1. What is a planetary system?Answer: A star together with the planets and other objects that orbit it.
  2. How do the eight planets generally move around the Sun?Answer: They orbit in the same overall direction and approximately the same plane.
  3. Which description best distinguishes terrestrial planets from jovian planets?Answer: Terrestrial planets are smaller and rocky; jovian planets are larger and mainly made of lighter materials.
  4. What is a meteorite?Answer: A rocky or metallic fragment that survives atmospheric passage and reaches the ground.
  5. What role does the International Astronomical Union have in naming features on other worlds?Answer: It approves names for features using international conventions.

Based on Astronomy 2e by Andrew Fraknoi, David Morrison, Sidney Wolff (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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