1 light year is equal to 5,878,499,810,000 miles, so 786,000,000,000,000 light years would be 4,620,500,850,000,000,000,000,000,000 miles. If every star in the Milky Way is a speck of dust, our galaxy would be the size of America. Furthermore, there are around 200 billion galaxies in the Universe. That being said, since it would take many stars to reach the distance of a light year, but there would be more than 4,620,500,850,000,000,000,000,000,000 specks of dust to make up a whole continent, we would be somewhere around the border of the galaxy. However, leaving our solar system would never happen as we would have no connection with Earth because of leaving the orbit of the entire solar system and we would have no way of getting back.