Entire Solar System
This simulation adds
3D arrows to show the gravitational forces (red arrows) between the bodies
in the Solar System, and their velocities (blue arrows).
As the arrows are not usually pointing in the plane of the screen, you should
play around with the tilt control to get a feel for where they actually are
pointing.
Unlike the 2D arrows (see the "Force and velocity" simulations) these arrows
aren't drawn from the centre of the object on which they act - but rather
from its surface, giving an additional visual cue to the direction of the
arrow.
Beyond a certain length - indicated by a bar across the arrow -
the arrows grow logarithmically (so that a doubling in force or velocity
would be shown as a fixed increase in length). This allows a much greater
range of magnitudes of force and velocity to be displayed side-by-side on
the screen.
Each object in the Solar System is attracted to every other one, but the
forces between the planets are far smaller than the mutual attractions between
each planet and the Sun, simply because of the Sun's overwhelming mass.
Looking at each inner planets and the Sun, you'll notice the matching forces
of attraction between them.
Each object (this is especially noticable with the Sun) has a number of different
forces (shown by line headed arrows) acting on it. This are added together
to give the total (or resultant) force on each object (shown by the solid
headed arrow).
For the Sun the resultant force is in the general direction of Jupiter (by
far the most massive planet).
For the planets, the attraction of the Sun is by far the most significant
force they experience, so the the resultant force towards the Sun overlays
the component force (towards it) which cannot be seen separately.
Even the Earth's attraction to the Moon scarcely deflects its attraction
to the Sun. The Moon's attraction to the Earth, however, does significantly
deflect its attraction to the Sun.