It was quite recent that NASA validated a seemingly impossible space drive known as em drive. It created lot of buzz in India as well as other parts of the world due to its characteristics and possibly working against newton’s laws. Similar engines were also quoted in Indian scriptures which totally drove the scientific juice if validation of this drive [ by NASA, i’am not saying that everything validated by NASA is ethical ] to a totally absurd path.
So why Em Drive is called to be a breakthrough?
Basically the engine is shaped like a trapezium with one side longer than the other. This closed space has light resonating which produces a net force in a direction. Now if we believe newton then for anything to move forward something has to be thrown backwards which is not the case in this engine. Take a look at Em Drive Wikipedia entry here.
So when we recall Newtons second or third laws that state that for and change in velocity or position, a net external force is needed. So to move forward we either need to push something backwards or throw a part of us in the opposite direction which is the case in most rocket engines where gases are thrown out in order to accelerate. But for example in cases where we need spacecrafts to travel large distances this type of rocket engines have their limitations. There is always a finite amount of fuel available which gets used up with time. With the use of EmDrive one can easily overcome this limitation.
As shown in the above figure, a closed body has light reflecting between its surfaces. One of the surfaces is having larger area than the other. If we believe the inventor, light resonating between these surfaces will produce a net force in the direction towards the larger plate. This controversial theory is not supported by most groups due to it seemingly violating the fundamental laws of physics. For detailed insight one can take a look at the official paper at SPR.
Recently NASA decided to test EmDrive and did find positive results. The tests continued for about 5 days and every possible parameter that could have caused the error was considered. The results were quite astonishing and it was concluded that the replica drive did generate a net force in a direction with magnitude of a few milli newtons. NASA avoided giving explanations on how this type of results were obtained saying it may be a case of interaction with quantum virtual plasma. Earlier Chinese researchers had also tested em drive with positive results.
[ update pending ]
If this supposed em drive finds applications after follow up tests, it would definitely revolutionize all types of travels. Read more on Wikipedia or the official site SPR which is the company Roger Shawyer established.