Time() Fatal error: Allowed memory size of 1073741824 bytes exhausted

After a lot of testing, wailing and gnashing of teeth, I think I’ve nailed down my problem to something about the time object. I began wanting to do a time comparison on the database (looking for overdue invoices, 30 days older than their due dates) when I kept getting “allowed memory size” error messages. As you can see, I bumped it up to 1gb, so at this point, memory had better not be the problem.

But it now appears that making a call to the Time object is the problem. Whether I use either of the two calls below - even outside of the query - I get the error message:
$today = Time::now(); $overdue = new Time('-30 days');
What is going on? Do I need something configured that hasn’t been?