Universo Viviente
Related Articles
In this series, we explore the weird and wonderful world of astronomical jargon! There is a lot to do with today’s topic: electromagnetism!
We have known about the characteristics of electromagnetic force for a long time. We knew the Sun generated light (and we wondered if the Moon did too). We knew we felt warm by the fire. We had discovered ‘lodestones’, which were seemingly magical rocks that always pointed north. We witnessed lightning and were wary of electric eels.
Over time, we have come to understand even more, especially through scientific investigation. We discovered that light can be described as a wave, and white light can be divided into rainbow colors. We discovered infrared radiation, which was invisible to us but acted just like any other light. We realized that the electricity from lightning was exactly the same as the electricity flowing through our nerves. We deduced that strong magnets can create weaker ones in particular types of materials.
From the 1800s, we slowly began to realize that it was all connected. Passing electricity through a loop of wire generated a magnetic field. A magnet passed through the center of the same hoop could generate an electric current. Two electric wires would attract or repel each other, just as two magnets could.
It was the Scottish physicist James Clerk Maxwell who figured it out in the 1860s. He developed a theory of electromagnetism that brought together all these disparate phenomena under a single theory. It was the greatest act of physical insight since Isaac Newton’s discovery that gravity was universal.
Maxwell’s work gave us electromagnetic force. The force that holds the magnet on your refrigerator is exactly the same force that powers your cell phone. It is also exactly the same force responsible for light; Maxwell realized that what we call light is just a collection of electric and magnetic waves traveling together.
The electromagnetic force is, along with gravity, the most familiar of the four forces of nature. Today, we know that the force is carried by photons, which are massless particles that have infinite range and travel at the speed of light. The complex interactions of photons are responsible for the rich variety of electromagnetism.
