How long until humans can reach a different star?
This is a question we don't know. We can't really predict when technology allowing us to make realistic journeys to another star will be available.
However,here is how long it would take us if we were going the speed of Voyager 1,which was going 38,610 mph: 73,353.84 years. This is only if we are going to the nearest star system which is 4.22 light years away. This is because 4.22 light years is 2.481 x 10^13 miles.
Now it's possible that in the future we could have new technology that allows us to do this much more quickly. However,my best bet is that if there is any technology that allows us to have much more feasible travel,it will be something that manipulates space time,not something that goes the speed of light. I say this because going the speed of light for a body that has mass would require infinite amounts of energy. It could be that in the very distant future we make this technology,it could be that we make it very soon,or it could be that it's impossible and the stars are forever out of our reach. We don't know.
It is actually almost impossible with today's technology.
Alpha centauri is the nearest star to the Sun which is about 4.243 light years away. A light year is the distance it takes for light to travel in one year (which is about 9.5 trillion kilometers).
One of the fastest moving human made objects is NASA's probe Voyager 1 that was sent to study the outer solar system and it actually left the solar system not that long ago and it was launched in 1977. Keep in mind that in space, there are no frictional forces such as air resistance. So, Voyager 1 is now traveling at this moment just as fast as it was before. Voyager 1 travels at a speed of 62,140 km/hr which is around 17.2 km/s
Now that's very fast! But hold on, if a space shuttle with a crew were to travel at the speed of Voyager 1 towards Alpha Centauri, it would take more than 75,000 years to reach its destination. Let that sink in for a minute. That is beyond our capabilities! It is absolutely impossible to hold supplies, resources, and fuel for 2700 generations.
Hopefully humans in the future get to solve this problem or else there is no possible way for interstellar travel.
At the present level of technology, about 6000 years, next question!
When the fastest we can make any vehicle travel is around 25,000 mph, and one light year is about 5,865696^12 (that's that number with twelve zeros after it) miles, you can now work out how long it would take to get to Proxima Centari at 4.25 light years distance.
No human will ever ever reach a star, at least not alive. They are far too hot. I s'pose it is possible that a manned space ship could one day be drawn into our star, the sun. But there would be no possibility of surviving the heat.
Far better to go to Florida, that is hot enough for me.
However if you are talking about visiting a different star system, similar to our solar system, don't hold your breath. Such a journey would take tens of thousands of years. Interstellar travel is strictly science fiction. No humans will ever ever make the trip. The distances are just too vast.
Best regards Bob