- #1
accelerate23
- 11
- 0
I know it has something to do with gravitational pull, but I don't know why.
Why does the moon orbit the Earth, and not the other way around?
Click For Summary
SUMMARY
The moon orbits the Earth due to gravitational forces and the principles of inertia as described by Newton's first law. Both the Earth and the moon orbit a common center of mass, known as the barycenter, which is located approximately 4700 km from the Earth's center. The gravitational pull of the Earth keeps the moon in orbit while the moon's forward motion creates an elliptical trajectory around this barycenter. This dynamic illustrates the balance of forces between the two celestial bodies.
PREREQUISITES- Understanding of Newton's first law of inertia
- Basic knowledge of gravitational forces
- Familiarity with the concept of barycenter
- Visualization of gravitational interactions using models
- Research the concept of barycenter in celestial mechanics
- Explore Newton's laws of motion in greater detail
- Learn about gravitational interactions in multi-body systems
- Investigate the effects of inertia on orbital dynamics
Astronomy enthusiasts, physics students, educators, and anyone interested in understanding the mechanics of celestial orbits.
- #2
hexhall
- 12
- 0
accelerate23 said:
Newton's first law of inertia states that all object in motion will continue in a straight line at a constant acceleration until acted upon by an unbalanced and outside force. In space, there is no friction to slow down and stop bodies such as the moon.
Gravity tries to pull the Earth and the Moon together. So, the moon is trying to move forward, while it is moving towards the Earth. Swing a string with a weight attached to the end of it around. The weight is trying to move forward, but the string prevents it. The end result: the weight orbits your hand.
A fun way to visualize this is to stretch a rubber sheet and pin it down, but it can't touch the ground (support it with books and such). Now put a marble on it. The marble will distort the rubber around it and all smaller marbles that touch the rubber and are close enough to this depression will go towards it. Einstein said that this shows that the first marble's gravity attracted the second. Now pick the second marble back up and roll it forward on the sheet. It will now "orbit" the first marble. Gravity!
- #3
accelerate23
- 11
- 0
thanks!
- #4
hexhall
- 12
- 0
accelerate23 said:
No problem. Always trying to help
- #5
rcgldr
Homework Helper
- 8,946
- 687
Both the moon and the Earth orbit around a common center of mass (barycentre or barycenter), which happens to be about 4700 km from the center of the earth, about 3/4 of the way to the surface of the Earth from the center.accelerate23 said:
- #6
johsun123
- 16
- 0
The larger body has momentum (m*v) at the same speed, so it takes the trajectory closest the center of mass of the two body system (barycenter).
Link
center of mass of the two bodies is going to form that eliptical trajectory, the barycenter will be inside of the larger body.
See another thread here in physics forums.
Link
center of mass of the two bodies is going to form that eliptical trajectory, the barycenter will be inside of the larger body.
See another thread here in physics forums.
- #7
accelerate23
- 11
- 0
Thanks(:
- #8
johsun123
- 16
- 0
I am no expert, but I had the same question and researched the answer.
Similar threads
- · Replies 19 ·
High School
Time to fall from 200 miles
- · Replies 8 ·
- · Replies 9 ·
- · Replies 17 ·
High School
To displace the Earth from its orbit
- · Replies 20 ·
Undergrad
Verse from "A Brief History of Time"
- · Replies 22 ·
- · Replies 4 ·
Writing: Input Wanted
How would an Earth-like Planet fair with a Uranus like moon system?
- · Replies 3 ·
- · Replies 2 ·
- · Replies 0 ·