GED® Science: Stars, Galaxies & the Universe
From the star next door to the edge of the observable universe — this course covers the astronomy portion of the GED® Earth & Space Science domain. You will learn how stars are born, live, and die; how the Hertzsprung-Russell diagram classifies stars by temperature and brightness; what our Milky Way galaxy looks like and how it fits into the larger universe; the evidence for the Big Bang and an expanding universe; and how astronomers measure cosmic distances. Every lesson uses real-world analogies, labeled diagrams, and GED®-style multiple-choice practice with full explanations.
📚 Course Curriculum
Stars are not permanent. Like living things, they are born, they age, and they die — but on timescales of millions to billions of years. …
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Not all stars look the same in the night sky — some are bright, some dim, some bluish-white, some orange-red. These differences reflect real physical …
Open trial session →The Hertzsprung-Russell (H-R) diagram is one of the most important tools in astronomy. It plots stars by two properties:. X-axis: surface temperature (note: temperature *decreases* …
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A galaxy is a massive system of stars, gas, dust, and dark matter held together by gravity. Our home galaxy is called the Milky Way. …
Open trial session →The Milky Way is just one of an estimated 2 trillion galaxies in the observable universe. Types of galaxies:. Type Shape Example. Spiral Flat disk …
Open trial session →How did the universe begin? The most widely supported scientific explanation is the Big Bang theory. Key idea: approximately 13.8 billion years ago, the entire …
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Measuring cosmic distances:. Space is so large that ordinary units (km, miles) become unworkable. Astronomers use:. Light-year (ly): the distance light travels in one year …
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Course Syllabus
Course Outcomes
📝 Practice Questions
23 interactive questions with instant feedback and explanations.
Enroll for free to unlock the full practice bank after the trial sessions.