The sun is a medium-sized star located near the edge of a disc-shaped galaxy of stars, part of which can be seen as a glowing band of light that spans the sky on a very clear night.
Learning Goal 1bc
The universe contains many billions of galaxies, and each galaxy contains many billions of stars. To the naked eye, even the closest of these galaxies is no more than a dim, fuzzy spot.
Learning Goal 2de
Some distant galaxies are so far away that their light takes several billion years to reach the earth. People on earth, therefore, see them as they were that long ago in the past.
Subchapter F
Motion
For Grades: 6-8
Learning Goal 3b
If a force acts towards a single center, the object's path may curve into an orbit around the center.
