1. The Fiction in Science fiction

2. Sound in space
Sound being a mechanical wave requires a medium (solid, liquid, gas) to travel through.
Since space is a vacuum sound cannot exist

3. Speed of sound Speed of sound in air ~ 341 m/s
Speed of sound in water ~ 1,481 m/s
Speed of sound in copper ~ 3901 m/s
Speed of light ~ m/s
(light does not require a medium to travel through)

4. Instantaneous radio communication
Radio waves travel at the speed of light (all electromagnetic waves do)
Therefore if someone was say 1 light year away from you and you were communicating via radio waves it would take 1 year for the first communication to be received.

5. Explosions in space
Explosions (combustion) can not occur in space since fire needs oxygen.
Space has no oxygen.
No oxygen, no fire

6. Gravity in space ships
There is no such thing as artificial gravity. There probably never will be as the energy required to do so would be massive.
Remember gravity is dependent on mass. A great deal of mass would be required.
Also the gravity would not be limited to the hulls of the ship.

7. Time travel

8. Time travel
While some scientist will argue that time travel is theoretically possible (there are rules) pretty everyone agrees its not feasible.
Too much energy would be needed
There are too many paradoxes
Can’t travel faster than the universal constant (speed of light)

9. Time travel rules You can see the past. You cannot travel to the past.
You can travel to the future.
You cannot see the future.