Proxima Centauri is 4.2 light years away from Earth, a distance that would take about 6,300 years to cover with current technology. Such a journey would be a long-term commitment, with most of the humans involved never seeing the Earth or its exoplanetary counterpart. One of the most distant exoplanets we know of in the Milky Way is Kepler-443b, located 3000 light years away. If you were to travel at the speed of light, it would take 25,000 years to get there.
However, from the perspective of a traveler moving at the speed of light, it seems that it doesn't take any time due to relativistic dilation of time. The light-year is a unit of measurement used to express distances to stars and other distances on a galactic scale. The TRAPPIST-1 system is made up of seven planets, all roughly in the size range of the Earth, that orbit a red dwarf star about 40 light-years away. It took almost a decade for New Horizons to get from Earth to Pluto, which is just around the corner, 4.6 light-hours away.
Light crosses interstellar space at 186,000 miles (300,000 kilometers) per second and 5.88 trillion miles (9.46 trillion kilometers) per year. Distances between objects within a star system tend to be small fractions of a light-year and are usually expressed in astronomical units. So how long would it take to travel 4 light years? Well, if you were to travel at the speed of light, it would take 25,000 years. But if you were to travel at 60 miles per hour, it would take an incredible 28 billion years.
And if you were to travel at the speed of modern technology, it would take 6,300 years.
