Stephen Hawking says the Earth will be a fireball by 2600

1) No physical craft can travel at the speed of light because that would give it infinite mass and require infinite energy. It would also cause time dilation according to Einstein’s theory of special relativity.

2) IF it were possible to travel at the speed of light, a trip to Alpha Centauri would take approximately 4.3 years, not 20 years.

3) No crew would survive a trip of that duration in space aboard a “tiny aircraft”. They would run out of food and water within days/weeks (assuming they didn’t perish from cosmic radiation, explosive decompression, or micrometeoroid impacts first). They would require a large ship, with massive engines, fuel reserves, and some kind of suspended animation or cryogenic hibernation to sustain even a small crew for that amount of time in deep space. No such technologies currently exist (or have even been tested). So this is not going to happen in a couple decades!