Possible issue with Rails Time parsing?

parse_time.rb

$ rails console
#Loading development environment (Rails 3.1.0.rc4)
> a = Time.now            # => 2011-07-26 01:37:59 -0500 
> b = Time.parse(a.to_s)  # => 2011-07-26 01:37:59 -0500 
> a == b                  # => false 
> c = a - b               # => 0.653716