Today’s Wonder of the Day was inspired by Andrew from New Orleans. Andrew Wonders, “How does electromagnetic propulsion work?” Thanks for WONDERing with us, Andrew!

Would you like to visit the Moon one day? That trip would be a dream for many people! The weaker gravity would let people leap through the air. Others would love the chance to see Earth from far away. Some think people might even live on the Moon one day. 

But why stop there? Why not travel to Mars? Saturn? Maybe even another galaxy? In today’s spacecraft, you’d be in for a long journey. A trip to Mars would take seven months. But that’s nothing—your flight to Saturn would last over three years!

Why does space travel take so long? There are many reasons. First, objects in space are very far away from each other. Our closest neighbor—the Moon—is 225,623 miles away. Mars? That’s 33.9 million miles! Traveling that far in even the fastest spaceship would take a long time.

Additionally, spacecrafts are very heavy. For example, NASA’s Space Shuttles had a liftoff weight of 4.5 million pounds. To make space travel faster, scientists have to figure out a way to make spaceships lighter. 

How would you make spacecraft lighter? Some scientists think the answer has to do with fuel. At liftoff, spaceships have to carry a lot of fuel. In the case of the Space Shuttles, fuel made up about half the weight of the entire craft at liftoff. Many believe that an alternative fuel method would make ships lighter and faster. 

One option is electromagnetic propulsion. It’s the use of electromagnetism to make objects move forward. That term may sound familiar if you’ve read about MagLev trains. In MagLev trains, electromagnetic propulsion works thanks to a linear motor. The train track pushes away the train’s electromagnets, forcing it forward. But how would that work in space?

An engineer named Roger Shawyer believes electromagnetic propulsion can also be used in spacecraft. Shawyer’s invention, the EmDrive, works with electromagnetic energy created within a cone-shaped thruster. Inside an EmDrive, electromagnetic waves flow from one end to the other. One end is much larger than the other, so the speed of the waves on one end is much higher. Shawyer says that this difference is what makes the EmDrive move forward. 

However, others are less sure. Many scientists chalk the EmDrive up to pseudoscience. They think it goes against Newton’s Third Law. This law states that for every action, there is an equal but opposite reaction. As the EmDrive does not seem to have a reaction, they argue that it doesn’t work the way Shawyer says it does.

Scientists are still testing Shawyer’s device. If the EmDrive does work, it would be a much cleaner way of space travel. The EmDrive would eliminate the need for spacecraft to burn fossil fuels. It would also make space travel much faster. Scientists estimate that traveling to Mars using an EmDrive would take 70 days.

Do you think electromagnetic propulsion is the future of space travel? What other uses could it have, if it works?


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