Cosmology Applet - Controls Explained Cosmo Home
INSTRUCTIONS:

Entering Data: At the bottom of the applet you will see a table for entering data. For each cosmology case you may enter a Hubble Constant, a mass parameter, and an acceleration parameter. Any invalid values or values outside these ranges will automatically be set to the closest appropriate value. Note: Only cosmology cases with valid values for the Hubble Constant and one of the parameters will be calculated.

Plotting Results: To plot your results click on the graph, or select your plot type (Lookback, Age, or Size) from the pulldown menu.

Analyzing Results: You can trace your data by clicking the trace checkbox below the graph and then clicking on the graph pane to give it the keyboard's focus. You can then use the left and right arrow keys on your keyboard to traverse a plot. The up and down arrows will cycle though the different cosmology cases. You can overlay data onto the Age plot by clicking the 'Edit Data Points' button. After entering the data values click the graph again to see the data points overlay. You can return to editing the cosmology cases by clicking the 'Edit Cosmologies' button.


CONTROLS:
Cosmology:
You may use this textfield to enter a description of this cosmology.
Hubble Constant:
Enter a value for the Hubble Constant (H0). Note that observational data suggest H0 is between 50 and 80 km/s/Mpc, but we allow a much broader range of values so that you can explore what happens with Edwin Hubble's original value of ~ 500 km/s/Mpc.
Omega Matter:
Enter a value for the Mass Density Parameter (OmegaM). For the purposes of this applet the value is constrained between 0 and 2.5.
Omega Lambda:
Enter a value for the Acceleration Parameter (OmegaL). For the purposes of this applet the value is constrained between 0 and 2.5.
Trace:
Toggles the tracing function on and off. Use the left and right arrow keys to traverse a plot. The up and down arrows can be used to change which plot is currently being traced. The checkbox will be 'greyed out' and unable to perform the tracing function if the graph doesnt not have keyboard focus. Simply click on the graph to give it keyboard focus.