Your Solar System
General Description
This program simulates the night sky of a fictitious solar system.
The program shows the apparent motions, as seen from Earth, of the Sun
and some planets relative to the background stars along the Ecliptic. The background
stars are the same as those seen from the real Earth, but the planets
are not the actual planets that we see. To make things a little
easier, all planets (including Earth)
orbit in a common plane and all orbits are circular and centered on
the Sun.
The simulation includes a clock that measures time in days, as well as
tools to measure elongation. By observing and measuring the Sun and
planets you can construct models for this fictitious solar system and
use these models to test certain astronomical theories.
Note that there are some differences between this simulation and the
ones we use in class for studying the Ptolemaic and Copernican
systems. In this simulation the planets are not indicated by
coloring. As in the real night sky, the planets look pretty much like
stars until you watch them move. The brightness of the planets may
not change in the same way as in the Ptolemaic/Copernican simulations,
but what is shown in this simulation is a more realistic depiction of
what we would see in the night sky if these planets were real.
Finally, planets are always shown to pass behind the Sun. This
does not really mean that the planet is behind the Sun - it simply
means that when the planet is right next to the Sun it is impossible
to see the planet because of the Sun's brightness. Real astronomers
have to deal with this same problem.
Ecliptic View Frame
- Visual Elements
- White spots: background stars or planets (you have to
figure out which is which).
- Orange disk: the Sun.
- Orange line: line marking the Sun's ecliptic longitude.
- Red line: line for measuring the elongation of any point
from the Sun.
- Red square: click and drag this square to move the red
measurement line left or right.
- Buttons
- Play/Pause button: play or pause the simulation.
- Step button: advance the simulaton by one time step.
- Step back button: moves the simulation back in time by one
time step.
- Reset button: reset the simulation to its initial state.
- Other Elements
- Clock (t): shows elapsed time in days.
- Speed slider: adjusts the speed of the simulation by
changing the size of the time step.
- Measure Elongation check box: select to show tools for
measuring elongation.
- Elongation: displays the angle (in degrees) between the
red and orange measurement lines. In other words, it shows
the elongation of the red line from the Sun.
Todd K. Timberlake (ttimberlake@berry.edu)