* The Milky Way is vast: It's a spiral galaxy about 100,000 light-years across.
* We don't have the technology: Even traveling at the speed of light (which is impossible for any spacecraft we know of), it would take 100,000 years to cross the galaxy.
* The galaxy is not a solid object: It's made up of stars, gas, dust, and dark matter spread out over a huge area. There's no distinct "edge" to reach.
What about traveling to the edge of our solar system? Even that is a very long journey. Our solar system extends out past Pluto to the Oort Cloud, which is estimated to be about 10,000 times further from the Sun than the Earth is. Even with the fastest spacecraft we have, this journey would take tens of thousands of years.
So, while we can explore our own solar system and nearby stars, reaching the "ends" of the Milky Way galaxy is a goal that's far beyond our current technological capabilities.
