# How does Einstein’s Theory of Relativity work?

Einstein’s work in the field of physics is simply impeccable. He has solved some major problems that became a significant base of a lot of our new research. He presented two theories of relativity. First is the general theory of relativity and the second one is the special theory of relativity.

In these theories, he made comparisons between bodies in a vacuum and non-accelerating bodies.

According to his special theory of relativity, the laws of physics apply to both the bodies in a vacuum and the non-accelerating ones. But no matter what, the speed of light will remain constant in all conditions.

Now, according to his general theory of relativity, every single body in the universe is attracted to one another with the forces of gravity. And the more space a body occupies, meaning, the bigger one object is, the stronger its force of gravity becomes.

The theory of relativity by Einstein conflicts between two universal laws:

## 1.Speed of relativity

It states:
Nothing can move faster than the speed of light. ## 2.Newton’s Third Law of Motion

It states:
For every action, there is an equal and opposite reaction (which mathematically is expressed as Force = Mass x Acceleration)

Now theoretically speaking, if you are traveling in a spaceship and the speed of your spaceship is just under the speed of light. For example, let’s say that it is 0.9999999999999% less than the light’s speed. Then, technically you are not breaking any of the above-stated laws. Therefore, you neither broke rule 1 nor 2. So there will be no problem, and you will be fine.

But keeping in mind the above scenario, let’s just say that you throw a sofa out of the back of your spaceship. What will this do? Well, according to rule no 1, you cannot speed up anymore. But according to Rule 2, you have to apply equal opposite force, and thus it says that you should speed up, which is not possible.

Confusing, right? The universe cheats.

Let us just break up this concept of force for better understanding. As we know,

Force = Mass x Acceleration

and,

Acceleration = distance/time x time

Therefore,

Force = mass x distance/time x time

Now we have all basic units, i.e. Force, Mass, Distance, and Time. If you ever get caught in the above-explained scenario. The universe plays with the basic quantities to protect the laws. To preserve Rule 1, the universe starts to mess with Mass and Time. It slows time down in fact, the faster you go, the slower time will move.

Still, confused? Well, one thing that you should also have knowledge of is the following equation of relativity by Einstein:

E = mc2

Here,

E = energy, m= mass, c = speed of light

That means,

Energy and time are interchangeable. So, if something travels at the speed of light, they travel in the time as it slows it down. Meaning that if someone achieves an unlimited range of speed, they can travel in the past.

As the theory of relativity says, when you really are going at 0.9999999999999% the speed of light, your rocket engine is actually a time machine. You turn on your rocket and instead of going faster, you make time slow down more and more from your perspective. Therefore, according to Einstein’s theory of relativity, nothing can move faster than the speed of light. But if someone does, then they will travel in time as they would have achieved a time machine.

You could travel across the galaxy in a few weeks if you just had a rocket that is big and fast enough. On earth, thousands of years would pass, but for you, it would be virtually no time at all.

Until now, no one has achieved this opportunity to build a rocket or spaceship that could run as fast as light. But, who knows, maybe someday scientists will come up with the solution to this problem. Perhaps someday we will get a chance to visit our past.

No matter what happens, there is one thing for sure. The field of science is just amazing. Indeed, it gives us the wings we require to conquer the world.