<...>
> >>> delta = b - a
> > => 42.0
> >>> p delta.days
> > 3628800.0
> > => nil
>
> right.  that is totally wrong.  the difference is only 42 seconds, therefor it
> should be a fractional day.  eg.
<...>

'days' and similar methods in Rails are core extensions and return
number of seconds.
So 42.days returns number of seconds in 42 days.

Useful for things like:

>> 10.minutes.ago
=> Wed Sep 06 12:56:52 FLE Daylight Time 2006
>> 3.days.since
=> Sat Sep 09 13:06:58 FLE Daylight Time 2006

Regards,
Rimantas
--
http://rimantas.com/