A "warp drive" is a time travelling device as much as it's a space travelling device.
Travelling to Alpha Centauri in 2 weeks means travelling about 4 years 3 months into the past. If that holds true then leaving today, spending 6 months "at warp", you could look back on Earth in the early 1960s. After a 2 year journey Earth could be seen in the early 1800s. Travel for 25 years, and see Earth in 500BC.