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The Hidden Lives of Galaxies - Classroom Activities

Activity #1 - How Big is the Universe?

In this activity, students estimate the size of the visible universe in relation to the size of the Milky Way Galaxy. To do so, students will get a sense of scale and will convert from centimeters to kilometers.

See Student Worksheet

Worksheet Answers

  1. What is the total size of the Milky Way Galaxy? 100,000 light years
  2. If the Milkyway Galaxy is represented by an 8 cm wide coffee mug, the visible universe would approximately 12 km in radius.


A service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC

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