Orbit

• Orbit


  The curved path of one celestial object or spacecraft around another celestial object
• Objects orbit rather than just flying off in a straight line or being pulled in towards the object they're spinning around
• Newton's first law


  An object traveling at a certain velocity will continue to travel at that velocity unless acted upon by a resultant force
• The moon is traveling at 1023 m/s


  It should continue to travel in this direction and at this speed forever
• The earth is so massive and relatively close to the moon

  It exerts a strong gravitational pull which is felt as an attractive force towards the earth
• The moon has a lot of momentum in its forward direction


  The gravitational force isn't strong enough to completely pull it in towards the earth
• The earth is always applying a gravitational force on the moon


  It's always changing the moon's direction
• Orbiting


  The moon is basically always orbiting around the earth
• The moon's speed is always the same


  Its velocity is constantly changing
• Acceleration


  Any change in velocity means an acceleration
• The moon changes direction as it orbits

  It's actually accelerating even though it's not getting any faster or slower
• Steady orbit


  • Instantaneous velocity of orbiting object
  • Gravitational pull of larger object
• The distance between the earth and the moon is smaller


  The size of the gravitational force will be much greater
• The moon's orbit is pulled inwards


  The moon would have to start traveling much faster to maintain a stable orbit and not be pulled in towards the earth
• Stable orbit


  The smaller an object's orbit, the faster that object must be traveling