Galaxies and gravity Earth in space Middle school Earth and space science Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! Earth is part of the solar system, which is part of a galaxy, which is part of a galaxy group. All of these systems are held together by gravity, a force that pulls objects with mass toward each other. Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere.…