Standard Twenty-one (21) Categories of the Electromagnetic Spectrum

A Base-10 Delineation By Wavelength
What Do We Understand About Each?


Please note: This page began in October 2018. Instead of these standard 21 base-10 levels of delineation, our model would have no less than 202 levels. Our work to understand each of those 202 notations will require years of work before truly becoming robust. Among many projects around the world, we are following the work of scientists  at Trinity College Dublin in Ireland.

Perhaps the most important part of this chart is that color spectrum of  lines defining visible light from 320 to 700 nanometers which is within Notation 88.

Questions:  What are the missing categories? How would  this scale go finer than one picometer (at the top)? A picometer  is equal to 1×1012 meters, or one trillionth (1,000,000,000,000) of a meter. Taken as a given, we will bump into the limits of physical  measurements.  That’s OK. What SI values are smaller than one picometer and larger than 100 Megameters (Mn) at the bottom of the chart?

The megameter (Mm) is a unit of length in the International System of Units (SI) defined as 106 meters using the SI prefix system, however Mn is rarely used. Instead exponential notation is extended using the meter or kilometer. So, 100 Mn in this chart on the left would be 108 meters. The next is gigameter, 109 (billion), then comes terameter, 1012 (trillion), or 1,000,000,000,000 m.

The next step up is the petameter, 1015 (quadrillion), or 1,000,000,000,000,000 meters. Beyond our sun, Alpha-centari is the closest star to Earth and is 4.366 light-years away which is 41.4 petameters.

The next group is defined by the exameter, 1018 (quintillion), or 1,000,000,000,000,000,000 meters. Zettameter (Zm) is the next step out, 1,000,000,000,000,000,000,000 meters (1 with 21 zeroes), Sextillion or 1021 meters. There is no star within our little Milky Way galaxy more than a zettameter away. The Andromeda Galaxy is 24 Zm from Earth (visible with an unaided eye).

The yottameter or 1024 meters (a septillion) is the current accepted limit of the SI extensions. Randy Bancroft, known on the web as The Metric Maven writes pointedly:

In 1991 both the Zetta prefix, and the Yotta prefix were added. The Yotta prefix allows us to write the distance to the farthest confirmed galaxy as 126 Yottameters (Ym). The end of the observable universe is approximately 435 Yottameters (Ym). The diameter of the universe is 870 Ym.”

Going smaller is also important. Currently the smallest unit of SI measurements is the yoctometer or 10-24 or a septillionth of a meter. The problem is our chart goes to the Planck base units of length; and time and within the time units, we are down to the 10-44 seconds and within the Planck Length scale we are down to 10-35 meters. Ten steps (groups) within the infinitesimal meter lengths will need names. And, twenty steps within the infinitesimal time lengths all need names. Anybody game?

Eventually we will try to integrate this work with the International System of Quantities.

Internal references: Our Chart, Time, Clock

External References: NIST, The Metric Maven, Electromagnetic Spectrum