It’s taken me a decade to realize this but I guess I’m just gonna ask about it now…..
Situation: you have a ship or fleet jumping into a system.
We are assuming the speed of light in systems is constant.
Warp or jump or whatever getting in to said system is irrelevant.
My question is: if you have something happen in a system that cannot be detected by ships coming into the system. Like a ship came in and destroyed another ship and it’s been long enough for the light of that engagement to pass so that other incoming ships don’t know anything about the engagement.
Why would you just not continuously send a repeating signal of what happed so as soon as anyone enters the system they would know immediately what has happened.
But Instead they choose to wait for a ship to translate in before telling said incoming ship.
Well because they want to tell incoming ships on their side but not enemy ships for one.
If it's not vital to the plot, the author probably just wouldn't put it in there. Good authors don't clog up and slow down the narrative with every possible contingency or explanation of technology they think of. They pick and choose.
The Vorkosigan series by Lois McMaster Bujold uses wormholes for long distance transport.
Signals can't transit wormholes, so there are ships that continually jump back and forth between the two ends of the wormhole to transmit news, mail, alerts, etc. towards the jump station, space station, or the planet in the system.
Jump Ships get around by travelling at a decent fraction of the speed of light between the space stations, jump stations, or planets and the wormholes.
There are times when you come out of your wormhole jump to emergency alerts, depending on the nature of the emergency. Also routine traffic alerts, notices of unusual activity, routing instructions, etc. Also, if the other side of the wormhole knows what's happening, you may be getting warnings from both ends.
If there's a major emergency that has affected the transmission ship from jumping back and forth, there may not be resources to replace it. But in that case, the jump point station or planet may be broadcasting warnings.
If there's a battle on, then there are military forces holding each side of the wormhole and they don't have time or actively don't want to warn people about what's happening on the other side of the wormhole. BUT lack of the usual transmission ship jumping back and forth can warn people something happened on the other side. You see this best in The Vor Game.
ETA: Some of the Hainish Cycle books by Ursula LeGuin take place after the invention of the ansible which can simultaneously communicate between two points anywhere in the galaxy, BUT you have to have the right half of the communication pair to do it. So you can pick up any messages sent by places on the other half of the communication pair that you have on board your ship, but not others. Books set before the ansible was invented have ships that travel at a significant fraction of the speed of light and that's how fast (slow) messages go, too. No wormholes.
Any series that uses the word ansible for simultaneous communication across light years got the word from LeGuin.
It feels like I’ve certainly seen “oh hey we jumped in and started hearing a repeating distress call, let’s go check it out”, I can’t remember any particular instances.
Are you thinking of a particular story where someone waited for a ship to drop in and manually contacted it? Maybe reasons were given there.
I try not to think too hard about communication in settings with FTL transportation. My rough understanding is that FTL would straight-up violate causality, and that it doesn't even usefully make sense to talk about things happening "simultaneously" or according to some universal clock. But also, it's not like I understand the math, so maybe I'm totally off-base!
I would actually be interested in reading a book that tackles some of these questions more directly. I have this vague idea that operating in a world with relativity is a lot like doing distributed computing at scale (where you also can't assume stuff like having a universal clock or a single point of view for the whole system). There are some cool logical/algorithmic questions there. Unfortunately, there aren't too many distributed systems experts who are also science fiction authors and, even if there were, the audience for a serious take on this idea has to be super narrow :P
The Mech Touch on Royal Road. Or..other sites.
Dread Empire's Fall or the Praxis by Walter Jon Williams. Interstellar travel is only through wormholes (no STL to get around this to another system). No FTL outside those wormholes either, so they're also a bottleneck on intersystem communications.
WJW uses this to good effect for battles - from ambushes to sneaking communications across.
Not a book, but the whole Babylon 5 series travel is based on jump points. Don’t remember about communication.
FTL Communication can take place by sending a transmission through a jump gate. However, this is rarely discussed or shown.
In most SF that isn’t hand-waving, the issue isn’t sending the signal, it’s trusting it. A continuous broadcast still propagates at light speed, so it doesn’t solve the timing problem. It just creates a standing wave of increasingly stale information. Incoming ships don’t know if what they’re receiving is current, spoofed, or even relevant until they’re close enough to verify it.
There’s also the tactical side. A constant beacon advertises that something important happened here, which is often worse than silence. Many settings treat information itself as a weapon. I think authors default to “tell them after translation” not because it’s the only option, but because it keeps causality intact and preserves uncertainty, which is where the drama lives.