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Speed of Radio Waves: How Fast Does Radio Waves Travel?

How Fast Does Radio Waves Travel on Earth or Moon or Sun

We use radio waves from television and cellular service to navigation and air traffic control. Still, we don’t often stop appreciating them and just how crazy fast they really are. So, how fast do radio waves travel anyway? 

Unimpeded, radio waves travel at the speed of light because they are part of the electromagnetic spectrum. In terms of miles, that means radio waves travel at approximately 186,000 miles per second or 300,000,000 meters per second.

If you’re a science lover or just curious about the technology that makes your life easier, you’ve come to the right place. In the sections below, we will break down how fast radio waves travel, whether they’re in space or here on earth. We’ll also answer interesting questions like how long it takes for radio waves to reach the moon or pluto. So let’s just dive right in!

How Fast Do Radio Waves Travel Through Space?

There is a common misconception that radio waves travel slower through space than they do through the air.

The truth is that radio waves travel at the speed of light, even in space. It just might seem like it’s taking them longer because space is so vast that even light and radio waves take considerable time to make their way across it. 

There are galaxies we will never be able to see because they are so far away from us that the speed of light waves can’t keep up with the expansion of the universe. The same, of course, would be true of any radio waves coming from a civilization outside the observable universe. 

How Long Does it Take for a Radio Signal To Reach Pluto?

To get some perspective on how vast the distances are that radio waves travel through space, let’s see how long it takes for them to travel from our friendly rock Earth to the dwarf planet Pluto.

It takes radio waves about four and a half hours to travel from Earth to Pluto. That’s because the waves must travel about three billion miles before reaching their destination. 

How Long Does it Take for a Radio Message To Travel From Earth to the Moon and Back?

Now let’s look at an object that’s a little closer. Our moon. The question is, how long does it take for a radio message to travel from the earth to the moon and back? 

Radio waves can travel to the moon and back at an average of about 2.56 seconds. Therefore if you sent radio waves on a journey to the moon and back, it would be the blink of an eye before they return.  They can make it quickly because the distance from Earth to the moon is only about 238,855 miles. When compared to the 92.5 million miles between Earth and the Sun, that’s nothing. 

How Long Does it Take for Radio Waves to Travel to the Sun?

You may be wondering, what about the sun then? How long does it take for radio waves to travel from the earth to the sun?

Radio waves take eight minutes to make their way from the earth to the sun. 

That may seem like a short period, but remember, these waves are traveling at the speed of light. This just goes to show how unbelievably big our solar system is, let alone the whole universe. 

How Fast are Radio Waves Compared to Other Types?

To really get an idea of just how incredibly fast radio waves to travel, you just need to compare them to other kinds of waves like sound waves and light waves. 

Below we’ve listed two other types of waves and their speed compared to radio waves:

  • Sound waves: Radio waves are a form of electromagnetic wave. Sound waves on the other hand, are a form of mechanical waves. Mechanical waves are not nearly as fast as electromagnetic waves because they are not made of light. Therefore sound waves can only travel 1,100 feet per second. That’s a far cry from the speed of light. 
  • Light waves: Like radio waves, light waves are also a form of electromagnetic wave. As such, light waves also travel at the speed of light. The main difference between light waves and radio waves is their frequency. 

The only thing that technically moves faster than the speed of radio waves or light isn’t a wave at all. The only thing faster than the speed of light is the expansion of the universe itself. That’s why radio waves outside the observable universe will never actually reach us.

Can We Detect Radio Waves From an Alien Civilization?

Let’s end on a fun note. Because radio waves can travel so far, so quickly, it’s only natural to wonder if we could detect radio waves sent out by an alien civilization living somewhere else in the universe.

While it is possible for us to detect radio waves from an alien civilization, the following issues make it less probable that we will:

  • The vastness of space: It’s hard to even wrap your head around just how ridiculously big the universe we live in is. Every indication we have now suggests that intelligent life is relatively rare, so knowing where to point our satellites is like a shot in the dark.
  • Radio waves diffuse: The real challenge is that as radio waves travel, they become diffused and unreadable. Therefore, if the advanced civilization is just a little too far away, it would be much harder to distinguish and interpret the radio waves they send. 

There have been scientific projects like SETI (Search for Extraterrestrial Intelligence) that have aimed satellites at the sky in the hopes of detecting a signal. Sadly, every single thing they’ve detected that seemed like it could be from aliens has turned out not to be so far. Still, the future isn’t written, so maybe someday that will be successful.

So Really, How Fast Do Radio Waves Travel?

The only thing faster than traveling radio waves is the expansion of the universe. That’s because radio waves actually travel at the speed of light or 186,000 miles per second. 

This means that radio waves could travel to the sun in about eight minutes and to Pluto in about four and a half hours. Considering the vast distances between us and those objects, we can definitively say radio waves travel quickly. 

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