Probes

Normally you will be told each turn about the worlds that you own, or at which you have fleets (or converts, if you are an Missionary.) Usually, the best way to find out current information about a world is to send a fleet there.

But it's also possible to get intelligence about a world without sending a fleet there. You can do this by sending a probe from a neighboring world.

A probe is a one-time ship you send through a connection without a fleet key. The ship is destroyed in transit, but it can send back an information report before it burns up.

Thus, each probe operation costs one ship, and can only be used to learn about worlds that are adjacent to worlds where you have a ship.

You can send an I-Ship or P-Ship as the source of your probe, or a ship on a fleet.