Does Light Travel in a Straight Line? Can It Be Bent?

Last Updated on Jan 27 2023

A basic principle of physics states that light travels in a straight line. It’s easy to prove, too. Simply shine a light through a parallel series of openings and it will pass through each one successively. You can also see it in real-time when looking at shadows. The division between the lighted area in the background and the object obstructing the light follows the perimeter. 

Keep reading to learn more about how light travels and more pertinent information regarding the subject.

Light vs. Sound

We can learn more about the properties of light by comparing it to another intangible force: sound. Sound is variable, depending on what it’s traveling through it and its temperature. At 59℉ at sea level, it will go 761.2 miles per hour (mph). That may sound fast until you start delving into Albert Einstein’s Theory of Special Relativity. Essentially, nothing can exceed the speed of light.

While sound is moving around at 761.2 mph, light is zipping along at a blazing 983,571,056 feet or 186,282 miles per second. It’s worth noting that this measurement is in a vacuum. Light sound, the medium—in this case, air—can affect its speed.

We can put the two properties in perspective with lightning and thunder. Remember that that bolt is moving 186,282 miles per second. The thunder is lagging behind at 1,100 feet per second. Both are moving at a constant speed, making it easy to calculate the distance between the lightning and the clap of thunder. Count the seconds between the two and divide by five to get the number of miles away.

If you’ve seen lightning strike, you’ll notice it’s following a straight path, although it may come at an angle. However, does that mean that light never deviates from this course? The answer is no.

Scattering the Light

If you’ve seen light shine through a cloud of dust, you may notice that it’s traveling in different directions. That’s the variations in the air medium changing with the suspended particles. Another classic example involves putting an object like a spoon in a glass of water. It will look like it’s bent. What you’re seeing is the difference between traveling through air and water.

Air is composed primarily of nitrogen, oxygen, water, and carbon dioxide. Of course, water is hydrogen and oxygen. However, there’s also the glass, which adds another factor to the mix. A prism will have a similar effect by refracting light into its various colors. However, we still have to dig a bit deeper. All things being equal, can light ever bend on its own?

Bending Light

Scientists thought that they had solved these riddles until they discovered the Airy waveform in the late 1970s. Researchers found that light could bend ever so slightly. Next, fast forward to 2012. The reason behind the discovery is based on heavy-duty mathematics and physics. Suffice to say that self-bending light is possible, opening up opportunities to use it for various purposes, such as redirecting lasers.

It might not be something that you would ever need to do. However, it does answer some questions. So, yes, light can travel in a straight line and also bend.

Final Thoughts

Understanding how light and sound travel tells us a lot about physics, mathematics, and science. It also shows us how much we have yet to learn about our planet and its place in the Solar System. While light does travel in a straight line, there are also times when it can bend.

Featured Image Credit: donatas1205, Shutterstock