The movie is from the 80s or 90s. (No it is not supernova). What I remember of the plot is that it's set in the future where a spaceship encounters another spaceship (if it was that the spaceship had been missing for a while in space, and they happened to find it or if they responded to a distress call, I do not remember)
But on board the other ship, there is an alien artifact that they had found, which later turns out to be a bomb that an alien race have created to destroy all other civilisations that who have mastered space technology. What I remember was that the bomb would explode if it came to earth and wipe out everything.
Does anyone remember the name of the movie?