Another idea on travel, a bit more crazy is a complicated idea I've thought through, possibly for a fictional book, since this invention is likely never to be created. The idea is to have a small very light ship, with a huge rear structure. Basically it is flat, about a mile in width, maybe 40 feet thick with a million tubes sticking out a ways. Particles of fuel or molecules/atoms of some type are accelated to about 10 to 80 percent of the speed of light and shot out the back. So using half the fuel results in moving at 4 to 36 percent the speed of light. That is amazing speed.

We could visit our nearest neighbor within years, but with accelaration at maybe 10 m/s/s it would involve years of accelaration and de-acceleration.

(for a visual, Image a clover mite siting on the back of an old pentium processor.