The concept of "empty space" can have different interpretations depending on the context. In the most common understanding, empty space refers to the vast regions of the universe where matter and energy are extremely sparse or absent. In this sense, reaching empty space would involve traveling away from any significant astronomical bodies, such as planets, stars, and galaxies.
However, it's important to note that even in the seemingly empty regions of space, there are still particles and electromagnetic radiation present, albeit in very low densities. These particles include cosmic rays, photons, and neutrinos, among others. Therefore, true emptiness in the sense of a complete absence of any matter or energy is extremely challenging to achieve.
If we consider "empty space" as an approximation for regions with very low matter density, then we would need to travel far beyond our solar system, galaxy, and even galactic clusters. The universe is vast, and the distances between astronomical objects are immense. To reach regions with significantly lower matter density, one would likely need to travel several light-years away from any major galaxies or cosmic structures.
It's worth noting that current technology and our understanding of the universe impose limitations on how far we can practically travel. At present, our most distant human-made object, the Voyager 1 spacecraft, has traveled approximately 23 billion kilometers (14 billion miles) from Earth, which is only a tiny fraction of the distance to the nearest stars.
In summary, reaching truly empty space, devoid of any matter or energy, is practically unattainable. However, to travel to regions with significantly lower matter density, one would need to journey far beyond the boundaries of our local cosmic neighborhood, spanning vast distances in the universe.