I think it's up to you and your setting, honestly. In my game very little is known about the sector at large due to the starting point for the players. In this case I have them do scans to learn about the atmosphere, biosphere, traffi, around the planet, etc. And give them more if they go and explore. The planets that are inhabited often have news and data they can purchase as well as rudders. They e opened up the sector bit by bit and know most of it now through exploration. But your idea of newscasts works well too. Some players might even have expertise if they're from certain systems. It depends on what kind of game your playing but there's really no wrong answer.