TBR: Planets/Solar System Question

[justadream]

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TBR Physics page 112 #17

"The true orbits of the planets in our solar system deviate from perfect ellipses. What could account for the deviation?"

One of the answers: The Sun itself is not stationary

TBR talks about the sun moving through the Milky way.

Ok.

But does movement of the sun itself actually CHANGE the orbits of the planets? Let's say you were in an isolated area (no other stars, no asteroids, nothing). When the sun moves, don't the orbits of the planets stay exactly the same? It'd be like picking up the entire solar system and moving it translationally.

I think it is really the gravitational effects (or other effects) of other STUFF in the Milky way that alters the orbits of the planets. The movement of the Solar System, itself, should have no effect.

 

[type12]

TBR Physics page 112 #17

"The true orbits of the planets in our solar system deviate from perfect ellipses. What could account for the deviation?"

One of the answers: The Sun itself is not stationary

TBR talks about the sun moving through the Milky way.

Ok.

But does movement of the sun itself actually CHANGE the orbits of the planets? Let's say you were in an isolated area (no other stars, no asteroids, nothing). When the sun moves, don't the orbits of the planets stay exactly the same? It'd be like picking up the entire solar system and moving it translationally.

I think it is really the gravitational effects (or other effects) of other STUFF in the Milky way that alters the orbits of the planets. The movement of the Solar System, itself, should have no effect.

1. We're moving pretty fast through the milky way.
2. You are either overestimating how much weaker gravity becomes with distance, or how distant we are from other celestial bodies. This might help:
http://en.wikipedia.org/wiki/Heliosphere
(while not correct, you can basically think of this as how far we need to be to "notice" something other than the sun or planets pulling on us gravitationally)

And the sun's movement does change the orbits. Imagine if you were all running around in a circle, and you have a string tied to the center of that circle, and you can feel the tug as you run around. Then that center starts moving to the left. What's going to happen? You'll feel a stronger tug and be farther away when you're rightmost, and lowest when you're leftmost, and up and down are indistinguishable.

Hope that helps.