That’s an interesting question. Proxima Centauri b is a planet that orbits Proxima Centauri, the closest star to Earth. The planet orbits its parent star at a distance of roughly 4.6 million miles (7.5 million km) with an orbital period of approximately 11.2 Earth days. Proxima Centauri b is only four light years away from Earth.
A solar sail is a spacecraft that uses the pressure of photons from the sun or other light sources to propel itself. The maximum theoretical speed a solar sail could reach is around 420 kilometers per second, or about 1/4 of the speed of light. However, this would require a very large and thin sail, and a close approach to the sun. A more realistic speed for solar sails is 10% of the speed of light, or 67,100,000 mph.
Assuming a solar sail could reach 10% of the speed of light, it would take about 40 years to travel to Proxima Centauri b. However, this does not account for the time it would take to accelerate and decelerate the spacecraft, or the effects of gravity from other bodies in the solar system. A more accurate estimate would require a detailed trajectory analysis and simulation.
I even asked Bing to calculate the time dilation for the person on earth. It answered correctly with the formula and steps shown clearly.
Aatube