Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
9 Cards in this Set
- Front
- Back
Solar System
|
~a collection of planets, moons, and other smaller bodies surrounding an ordinary star that we called the Sun.
|
|
Planetary System
|
System of planets surrounding a star.
|
|
Our Solar System is a tiny part....
|
of our galaxy, which is a tiny part of the universe.
|
|
Self-gravity
|
~holds plants and stars together.
~Gravitational attraction between planets or stars that pulls all the parts towards its center. ~Inward force= structural strength ~Outward force= gas pressure in the star ~Outward force<self-gravity=objects contracts ~Outward force<self-gravity= it expands ~Stable object is = |
|
interstellar medium
|
opposing forces of self-gravity and internal pressure
|
|
interstellar cloud
|
~a relatively dense region of the interstellar medium
~has self-gravity ~internal pressure > self-gravity = expanding ~opposing pressure = hotter gas, hold them together |
|
Pressure is proportional to
|
both density and temperature
|
|
Molecular clouds
|
~densest, coolest clouds
~conditions within them allow hydrogen atoms to combine to form hydrogen molecules ~massive enough, dense enough, and cool enough= self-gravity overwhelms internal pressure and collapses ~the collapse would be quick |
|
Turbulence
|
~the random motion of pockets of gas within the cloud
|