Invited Paper VT-WeA1
The 14-billion Year History of the Universe Leading to Modern Materials Science

Wednesday, November 1, 2017, 2:20 pm, Room 20

The story of our universe begins approximately 13.8 billion years ago with the Big Bang. Many of the formative events occurred in the first tiny fractions of a second (the universe evolved from consisting of a quark/gluon plasma to form the first protons and neutrons) to minutes (free neutrons decay to electrons and neutrinos) to a few tens of thousands of years (elementary particles form the first elements, which leads to the development of stars due to local density fluctuations). Planet Earth nucleated and began to accrete interstellar debris ~4.5 billion years ago. While the lighter metal elements on earth formed primarily due to stellar supernovae explosions, the primary mechanism leading to the formation of the heavier elements has only recently been demonstrated. The first known sophisticated stone tools used by hominids date to 2.6 million years ago.

Gold is likely the first metal discovered by man, >11,000 years ago. However, unlike copper (~9000 BC), bronze (~5000 BC), and cast iron (~600 BC), it was too soft for fabrication of tools and weapons. Instead, gold was used for decoration, religious artifacts, and commerce. The earliest high-purity Au artifacts derive from NE Bulgaria ~6500 y ago; however, the largest known concentration of ancient gold mines is in the Egyptian Eastern Desert. Copper extraction from ore was already being carried out in the Balkans (E Serbia and S Bulgaria) ~7500 years ago. Spectacular copper sculptures displaying very high levels of metallurgical and artistic craftsmanship have been found in Mesopotamia (S Iraq).

Gold brazing of metal parts was first reported ~3400 BC in Sumaria. The earliest documented thin films were gold layers, some < 1000 Å thick, produced by Egyptians ~5000 years ago. Examples, gilded on copper and bronze statues and artifacts (requiring sophisticated compositionally-graded interfacial adhesion layers), were found in pyramids dating to ~2650 BC. Electroless gold and silver plating was developed much later by the Moche Indians of Peru in ~100 BC.

Early biomaterials, used as human prosthetics following successful amputations, date to 950 BC in Egypt; while the first nano-based devices, exhibiting spectacular dichroic effects due to ~200-Å-diameter Au quantum dots, were synthesized in Rome ~350 AD.

Vapor-phase deposition of thin films required the invention of vacuum pumps (~1650 through 1865). The fascinating development of crystallography begins with Plato in 360 BC.