Even if you don't have your finger on the pulse of the latest propulsion technology, you probably heard the news that scientists had managed to invent an EM drive that baffled even NASA. It's been hailed as the answer to interstellar travel, but what is it? Essentially, the EmDrive is a type of engine that doesn't require any fuel, known as a "reactionless" engine. This, however, breaks some pretty important rules, name Newton's third law which states that For every action there is an equal and opposite reaction. As there is no reaction (i.e. the burning of fuel), the drive should not move. However, there are tentative reports that the drive appears to work, which means that we've either misunderstood how it works, or we need to rewrite some major physical laws. By cutting out the need for fuel, the EmDrive allows the weight of spacecraft to be cut dramatically, making them cheaper and lighter to get into space. It is also theoretically capable of immense speeds, potentially enabling us to reach the edge of the solar system in a matter of months. The "impossible engine" continues to baffle scientists, who are convinced that it shouldn't work, but work it does.
