Next week marks the closest approach to Earth of the rather insignificant asteroid 8103 Fermi. This asteroid was discovered in 1994 from an observatory in Farra d’Isonzo, Italy. This small observatory was established in 1975 by seven students, average age less than twenty. They raised money for their first telescope by running film nights for kids and collecting and selling scrap metal. With their proceeds they purchased a 20 cm telescope and housed it in a self-built sliding-roof shed. They were later able to upgrade to a 40 cm telescope and by the early 90s had added a CCD camera to be able to image faint objects. In their first year with the CCD 13 new objects were discovered, the following year they found another 39. Discovery of an asteroid allows for naming rights, so there is an asteroid Isonzo, an asteroid Farra, as well as some notable Italians in asteroid Rubbia, dedicated to the scientist who won the Nobel Prize for Physics in 1984 and asteroid Fermi, named for the second Italian to win the Nobel Prize for Physics.
Born in 1901 Enrico Fermi was a theoretical and experiment physicist, known initially for his work on beta decay and producing new elements by slow neutron bombardment. It was this that led to him being awarded the Nobel Prize in 1937. He and his family attended the prize giving in Stockholm and did not return to Italy, instead heading to New York and applying for American residency. He took up a position at Columbia and later moved to the University of Chicago as part of Met Lab – a component of the Manhattan Project. He was in charge of building the first self-sustaining nuclear reactor. This was made of wood, with a pile of graphite bricks and uranium pellets. Control was achieved by inserting and removing cadmium coated rods. Fermi described it as “a crude pile of black bricks and wooden timbers.” The pile had no radiation shielding and no cooling, Fermi having convinced Arthur Compton, the leader of the project, that his calculations were reliable enough that there would be no run away chain reaction. Compton rang in a report of the success to the Chairman of the National Defense Research Committee with these words:
Compton: The Italian navigator has landed in the New World.
Conant: How were the natives?
Compton: Very friendly
Fermi attended the first atomic bomb test on July 16, 1945 and used what is now called a “Fermi problem” approach to estimate the yield of the bomb. He later wrote:
“About 40 seconds after the explosion the air blast reached me. I tried to estimate its strength by dropping from about six feet small pieces of paper before, during, and after the passage of the blast wave. Since, at the time, there was no wind, I could observe very distinctly and actually measure the displacement of the pieces of paper that were in the process of falling while the blast wave was passing. The shift was about two and a half meters, which at the time, I estimated to correspond to the blast that would be produced by ten thousand tons of TNT.”
He was known for this approach to complex problems and in 1950 he formulated the Fermi Paradox. In essence he asked “where are they?” in reference to advanced extra-terrestrial civilizations. He argued that given the size and age of the Milky Way there should be lots of extra-terrestrials, his paradox rests on the fact that we have not detected them. The Fermi paradox has a multitude of possible solutions, some rather more far-fetched than the others. Fermi did not live to see it being taken seriously; he died of stomach cancer in 1954.