Dear god, there was a solar system simulation on the macs in my middle-school library (c. 1998) that I sunk absolutely inordinate, ridiculous amounts of time in

Dear god, there was a solar system simulation on the macs in my middle-school library (c. 1998) that I sunk absolutely inordinate, ridiculous amounts of time into. I think it had a 10-body limit and may have been much older (was definitely monochrome, and possibly used lines of varying density for shading). I can't remember what it was called and I haven't been able to find any information about it. It may be my favourite single piece of software ever and I am certain it had some nontrivial effect on the course of my life[0]. Can anybody help me out? [0] Including nurturing several destructive habits and attitudes, such as on the acceptability of spending grade-school lunch hour on the computer every day.