JASLab
Home
About Us
Attosecond Science
Research
Facility
People
Publications

Attosecond Science Tutorials

Time and the Organization of the Universe

Time organizes the universe from its beginning to the present. We measure time by the ticking (vibration) of electrons is atoms -- the atomic clock. Atoms make exquisitely reliable clocks.

Atomic clocks have ticked in the universe since shortly after it began -- in fact, for so long that we use light emitted or absorbed by atoms to measure the distance to far away galaxies and to estimate the age of the universe. 

The outer electrons in most atoms complete one vibration in 100 – 1000 attoseconds. The most natural clock is hydrogen, the simplest atom. The universe began about 10,000,000,000,000,000,000,000,000,000,000,000,000 ticks of a hydrogen atom ago. 

The electron that ticks in the atomic clock existed even before atoms formed. Similar electrons, of equal antiquity, hold all molecules together. This includes the DNA that gives you life, the molecules that make up the chair on which you sit and the complex molecular process by which you see the computer screen.

At NRC, we work on the time scale of electron vibrations in atoms -- attoseconds. On this time scale (1/1,000,000,000,000,000,000 of a second) our life, which takes place on the second time scale, seems frozen; that is, nothing in our daily leaves appears to take place on that timescale, yet -- could we but see it, the world of atoms and molecules (including the basic building blocks of life) is teaming with activity. 

At the attosecond time scale, electrons move, interact, exchange places. Like the planets moving around the sun, the slowest electrons (planets) have the largest orbits. These are the attosecond electrons. Small orbit (core) electrons can move even faster. The slow-moving electrons are responsible for the chemical bonds that hold molecules together which makes them responsible for our life. All chemical and biological reactions are mediated by these electrons.

On the attosecond time scale the atoms in molecules move imperceptivity. On the femtosecond time scale, however, they are in constant vibrational motion. Since chemistry is the process of rearranging atoms, the femtosecond time scale is the fundamental time scale of chemistry. Chemical reactions power your body, making the femtoseond time scale important to life. 

Molecules rotate on the picosecond time scale. A picosecond is 1 million attoseconds. 

For many chemical reactions, molecules must find each other. This is somewhat like meeting a neighbour in a crowded shopping centre. As you know, it takes a while to find each other. In the world of atoms and molecules, diffusion can take nanoseconds (or longer). Frequently the speed of chemical and biological processes is paced by the need to find suitable partners. 

Back to Attosecond Science Tutorials Page