Microwave

Say the word microwave to the average person today and they'll think you're talking about a microwave oven. But microwave ovens derived their name from the microwave technology they use to cook food, a technology that was being used in the fields of telecommunications and astronomical research long before it was used to heat leftovers.

What is a microwave?

Microwaves are electromagnetic waves. The wavelengths or radio frequency ranges considered to be microwaves are actually somewhat arbitrary, but the approximate range is 1 GHz (gigahertz) to 300 GHz. One GHz is equal to one billion oscillations per second.

Microwave wavelengths can also be measured in centimeters. A 1 GHz microwave is 30 centimeters, while a 300 GHz microwave measures 1 millimeter. The microwaves used in microwave ovens to cook food are about 12 centimeters.

The earliest experiments in microwave technology occurred near the end of the 19th century. Because of their high frequencies and short wavelengths, microwaves were eventually found to be ideal for use in telecommunications and radar. Their short wavelengths could be controlled by small antennae that permitted energy to be confined to a tight beam, which in turn made information more secure and harder to intercept.

Today, microwaves are used in a variety of applications, including radar, Bluetooth, and transmission of television signals.

Where do microwaves come from?

Microwaves can be created technologically through the use of solid state devices and vacuum-tube based devices. But microwaves also exist in nature.

In 1964, two scientists at Bell Laboratories, named Arno Penzias and Robert Wilson discovered, while using a low noise antenna, that background noise was coming from everywhere. What they had discovered was that low-energy microwaves fill the entire universe with background radiation. These microwaves were eventually identified as a radio remnant of the Big Bang, and given the name cosmic microwave background radiation, or CMB.