REVIEW

2. the chemistry of the earth
4. were often written in the form of “if, and, then” statements, as in, “if my hypothesis is true
7. are areas where the Earth's plates move past each other, rubbing along the edges
10. long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries
14. commonly used very loosely to refer to a body of explanation that is already validated or note yet validate
16. published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other
18. is a unifying principle that provides a well-substantiated and testable explanation of aspects of nature and provides the reason for why things happen
19. the milky way is a part of this cluster
20. appears as a milky band of light in the sky when you see it in a really dark area

1. a natural phenomenon that occurs in space with some regularity for it lies in the natural cycle of a star's life
3. is to discover laws and postulate theories that can explain natural or social phenomena, or in other words, build scientific knowledge
5. described as shields, in which the basement rock crops out at the surface, and platforms, in which the basement is overlaid by sediments and sedimentary rock
6. the coolest and most rigid part of the Earth
8. idea that a spinning cloud of dust made of mostly light elements, called a nebula, flattened into a protoplanetary disk, and became a solar system consisting of a star with orbiting planets
9. building blocks of life
11. is a model of cosmic evolution according to which the universe undergoes endless cycles of expansion and cooling, each beginning with a “big bang” and ending in a “big crunch”
12. a seafloor mountain system formed by plate tectonic
13. extremely hot liquid and semi-liquid rock located under Earth's surface
15. universe expands exponentially fast, its geometry becomes flat—this geometry was confirmed experimentally around 2000
17. a major Milky Way structure that crosses the Perseus arm , linking the Sagittarius and Outer arms
20. the mostly-solid bulk of Earth's interior