released α particles which had an energy of 8.6 MeV and decayed with a half-life of 8 ± 2 seconds. These particles can only be produced by element 103, which, according to one scientific theory, is a type of "dinosaur" of matter that died out a few weeks after creation of the universe.

The half-life of lawrencium (Lw) is about 8 seconds, and its mass number is thought to be 257, although further research is required to establish this conclusively.

Research on lawrencium is complicated. Its total α activity amounts to barely a few counts per hour. And, since scientists had the α-particle "footprints" only and not the beast itself, the complications increased. Therefore no direct chemical techniques could be used, and element 103 was the first to be discovered solely by nuclear methods.[A]

For many years the periodic system was considered closed at 92. It has now been extended by at least eleven places (Table I), and one of the extensions (plutonium) has been made in truckload lots. Its production and use affect the life of everyone in the United States and most of the world.

Surely the end is again in sight, at least for ordinary matter, although persistent scientists may shift their search to the other-world "anti" particles. These, too, will call for very special techniques for detection of their fleeting presence.

Early enthusiastic researchers complained that a man's life was not long enough to let him do all the work he would like on an element. The situation has now reached a state of equilibrium; neither man nor element lives long enough to permit all the desired work.