5.4 Key Terms

Nebula: a giant cloud of gas and dust. 5.3

Nebular hypothesis: the Sun and the planets of our solar system formed about 4.6 billion years ago from the collapse of a giant cloud of gas and dust, called a nebula. 5.3

Planetesimals: large clumps of matter that attracted smaller clumps with their gravity. 5.3

Protoplanets: former planetesimals formed through the gravitational attraction of more massive particles, such as rock and metal. 5.3

Terrestrial planet: any of the planets Mercury, Venus, Earth, or Mars; sometimes the Moon is included in the list. 5.1

License

Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Fanshawe College Astronomy Copyright © 2023 by Dr. Iftekhar Haque is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.