Traveling a distance of 4 light years poses significant challenges, mainly due to the limitations of current human technology and our understanding of physics. A light year is the distance that light travels in one year, which is about 5.88 trillion miles (9.46 trillion kilometers). To put this in context, traveling 4 light years means covering approximately 23.2 trillion miles (37.2 trillion kilometers).
Currently, the fastest spacecraft built by humans, the Parker Solar Probe, travels at about 430,000 miles per hour (700,000 kilometers per hour). At this speed, it would take over 6,700 years to reach Proxima Centauri, the closest star system to Earth, which is about 4.24 light years away. Other space missions, like the Voyager spacecraft, travel significantly slower, making the journey to even nearby stars last tens of thousands of years.
Considering theoretical concepts, if humanity were to develop technology like a warp drive or utilize near-light-speed travel, the time taken could be reduced dramatically. For instance, if a spacecraft could travel at 10% of the speed of light, it would still take about 40 years to cover 4 light years. Yet, these technologies remain in the realm of science fiction and speculative science.
In summary, using existing technology to travel 4 light years would take an impractically long time, potentially thousands of years. Future advancements might hold the key to shorter travel times, but for now, interstellar travel remains a largely theoretical endeavor.