Unlike the hostname -I command, which just lists all configured IP addresses on all network interfaces, the hostname -i command performs name resolution (see the hostname man page).
Since your newly assigned hostname cannot be resolved using the /etc/hosts file, running hostname -i will cause your system's name resolver to generate a DNS query to an external DNS server. At this server (which I presume belongs to your ISP), this query comes up empty (NXDOMAIN result: i.e. non-existent domain). Because your ISP has partnered up with Barefruit, rather than receiving the NXDOMAIN result, you receive a Barefruit IP address in response to your query:
$ dig +short -x 92.242.140.21
unallocated.barefruit.co.uk.
I imagine that adding your new hostname to your /etc/hosts file will make the weird Barefruit IP address disappear when you run the hostname -i command. If not, you may disregard this answer : )
Just for the fun of it: using the dig command, you can interrogate different name servers. To see the difference in response, you could run the following two commands:
$ dig saturn
$ dig @8.8.8.8 saturn
The first causes name resolution via your system's preconfigured DNS server, and likely results in a Barefruit IP address being returned. The second command asks Google Public DNS to resolve the name, and returns with an NXDOMAIN status. Or not?
If so, your ISP may be involved in the dubious practice of DNS hijacking, and you may want to figure out if there is an opt-out possibility, or change your DNS service provider.
