Travelers In The Night

Marie Curie's discovery of radioactivity started humans on a path which so far has skirted annihilation and has led to cures for cancer and the exploration of the distant regions of our solar system.If you want to get an idea about what our knowledge of the solar system would be like without Radioisotope Power Systems, go to a used bookstore or the library and find an Astronomy text book from the mid 1970's and well as a current one. Look up the planets in both.