There's an icon in this game that confuses me because I have no idea what it represents.

It looks like a filled-in circle, in parentheses, with an arrow pointing downwards below the filled-in circle.  This entire icon is in a circle (not filled-in).

You can see this icon when you start up a new game, click on your home planet, and look at the image of the planet, where the "View" button is.  It's in the top right of that small, square, planet image.

Thanks in advance for helping a newb.