One day, millions of years (1) in the future, the Sun (2) is going to explode. Unfortunately, we can't prevent this (3) from happening and it means that humans won't (4) be able to live on Earth anymore.
Luckily, we (5) have lots of time to prepare (6) for it. It's likely (7) that this preparation will involve working out how to travel very long distances through space, and (8) find another suitable planet to live on. We (9) shall need a planet that doesn't go round the Sun but orbits another star instead. The nearest one is a very (10) long way away. With the technology we have today, the journey will (11) take 50,000 years!
If we can discover a way to travel much faster - at just below the speed of light - then the journey will (12) be very quick: only six years!