It is a remarkable, reasonable universe essentially governed in the physical realm by essentially 4 forces. We sent up a space probe in 1977 and it is traveling at about 17,000 miles per hour, and it is only now leaving our solar system. That is 35 years (roughly) moving at 17,000 per hour, each hour for 35 years and it is only now leaving our solar system.
Ok- Lets blow up a balloon and lets say our galaxy as we know it and all we know is inside that balloon— then whats beyond the ballon (or whats holding up the balloon)and beyond the next— it must keep going forever— there is no beginning of space and no end to it.