1-2) Mass/ gravity/ distance
- Gravity attracts all objects toward one another.
- If the mass increases, the force also increases.
- If distance increases, force decreases.
- The strength of gravity is affected by the distance between two objects as well as their mass.

1-3) Gravity/ mass/ weight
- Mass is the amount of matter on an object.
- The force of gravity on an object is weight.

2-1) How does gravity control the motions in our solar system?
- Gravity is very important to force. Every object in space exerts a gravitational pull on every other, and so gravity influences the path taken by everything traveling through space.
- It is a glue that holds entire galaxies.

2-2) Sun, moon, planets, asteroids, other orbits
(How do they work?)
- The factor is called inertia.
- interia: The tendency of an object to resist a change in motion.
- Orbital Motion: Newton concluded that two factors-inertia and gravity- combine to keep Earth in orbit around the sun and the moon in orbit around Earth. Earth's gravity keeps pulling the moon toward it, preventing the moon from moving in a straight line. At the same time, the moon keeps moving ahead because of its inertia. If not Earth's gravity, inertia would cause the moon to move off through space in a straight line. 

3-1) How stars are born?
- When atoms of light elements are squeezed under enough pressure for their nuclei to undergo fusion.
- Force of gravity compresses atom interstellar gas until the fusion reacts begin.

3-2) Formation of planets
- Terrestrial planet: 
a. Small protoplanets revolve around the orbit
b. Sustain instability condition.
c. While they sustain the condition, protoplanets attract each other and run into other planets
d. pieces stick together
e. This piece includes Mercury, Venus, Earth, and Mars.

3. What role did gravity play in the creation of our solar system?
The sun's great gravity pulled on the planet near by in orbit of distance and mass, and create the Solar System.

 

-Definition of Gravity: A force that attracts all objects toward each other 

-Type of force that gravity is: Pulling 

-Mass: amount of matter in an object 

-Weight can change depending on its location like on different planets 

-Strength of force of gravity between 2 objects depends on 2 factors=masses of objects/distance between them 

-Distance: Strength of gravity is affected by the distance between 2 objects/masses 
 

How does gravity control the motions in our solar system?
 -Sun/Earth=constantly pulling on one another because of gravity 

-Earth doesn’t fall in sun/Moon doesn’t fall in Earth—Factor-Inertia 

-Inertia-Tendency of an object to resist change in motion 

-More mass object of has=greater inertia 

-Newton’s first law of motions-object at rest will stay at rest/object in motion will stay in motion without being stopped 

-Earth/moon remain their orbits—Inertia/Gravity 
 

-Solar nebula-giant cloud of gas/dust formed our solar system maybe by an explosion of a star-supernova 

--Planets created by Gravity of rock and minerals 

-Then Gravity pulled most gas in center of disk== Sun creating 

-Planetesimals-Gas/dust formed small asteroid-like bodies/formed building blocks of planets/eventually becoming planets 

-Inner planets-When solar system formed temp=high/gases escaped gravity forming inner planets/terrestrial 

-Outer planets-As planets grew gravity increased/capture hydrogen/helium h=gas in surrounding space 

 

-If it wasn’t for gravity you would be floating around on earth. For example, with gravity, when you jump you will automatically be pulled down towards the center of Earth, without gravity you would just stay up in the air. 

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