Okay, people, I'm assuming I missed the dialogue that explains this:
Lighting up the hugest beacon in the Universe is not going to accelerate all those lumens past 186,000 miles per second.
So that "new star" of Sarek's - what is it and where is it?
Star Trek has never suggested (that I recall) that humans, Klingons or the other usual suspects can pick up real-time light emissions across light years with their sensors.* So everyone's getting this off of something like the relay that Shenzhou was repairing, right? The Klingons, Starfleet...
*Maybe, sorta in the episode "Tin Man."