Physics of the Impossible 2

The concept of impossibility

According to Kaku, technological advances that we take for granted today were declared impossible 150 years ago. William Thomson Kelvin (1824–1907), a mathematical physicist and creator of the Kelvin scale said publicly that “heavier than air” flying machines were impossible. “He thought X-rays were a hoax, and that radio had no future.”[4] Likewise, Ernest Rutherford (1871–1937), a physicist who experimentally described the atom, thought the atom bomb was impossible and he compared it to moonshine (a crazy or foolish idea). Televisions, computers, and the internet would seem incredibly fantastic to the people of the turn of the 20th century. Black holes were considered science fiction and even Einstein showed that black holes could not exist. 19th century science had determined that it was impossible for the earth to be billions of years old. Even in the 1920s and 1930s, Robert Goddard was scoffed at because it was believed that rockets would never be able to go into space.[4]
Such advances were considered impossible because the basic laws of physics and science were not understood as well as they are understood today. Kaku states that “as a physicist [he] learned that the impossible is often a relative term.” By this definition of "impossible", he poses the question "Is it not plausible to think that we might someday build space ships that can travel distances of light years, or think that we might teleport ourselves from one place to the other?"