The first thought that comes to everyone's mind when they hear the term 'theoretical physics' is? Of course, Albert Einstein! Those long mathematical equations, the meaning of which is complex to understand, to derive them using mathematics is challenging. But that is the beauty of it. To invent and imagine something that our day-to-day conscious will never think of is brilliant!

The Physics Is Theoretical, But The Fun Is Real!

The world of theoretical physics is not result-driven, no one can know beforehand what the final equations will express, what layer of truth it will expose, and the reality that comes forward is extremely unanticipated. Most of the time it contradicts common sense. The theory is given more attention, than designing the experiments necessary to prove the assumptions and ultimately the theory. It is purely mathematical until proven by real experiments.

**Theoretical Physics:**

**"The development of mathematical formalisms and computing methods for describing all characteristics of things present in our surroundings and their interactions. This can include both developing models for comprehending empirical data and building self-logical theories to explain events that go beyond the scope of existing research."**

There are two things that theoretical physicists do. One, they have a dataset and they have to devise a theory that best explains that data. Two, there's new data collected for an already existing theory and the old theory need some updates. The validity of the theory is judged on how much it agrees with empirical data. A physical theory is a set of connections between different observable quantities. Pythagoras knew the relationship between the length of a vibrating string and the musical tone it generates, whereas Archimedes discovered that a ship floats by displacing its mass of water.

To comprehend theoretical physics, one must first comprehend the idea of theory. Theories are simplified representations of complicated systems. The universe is an intricate structure. To examine the cosmos in the way that physics does, it must be broken down into fundamental principles and basic concepts that result in a simulation or model.

A theory must be helpful in that it approximates reality while also making it intelligible, quantifiable, and predictable. To develop a theory, start with assumptions or postulates. An assumption is anything that is accepted without evidence. As a result, the assumptions constitute any theory's weak spot, and hence the fewer the assumptions, the more helpful the theory. The assumptions should then result in a theory that explains reality, and actual observations should be described and even predicted by the theory. As a result, the theory's predictions may be put to the test.

A hypothesis, on the other hand, can be disproven if two contradicting conclusions can be formed from it. The scientific approach employed in modern times to verify the feasibility of a theory is to extract a required inference from the theory and then rigorously test it against actual facts. This is known as experimenting. When assumptions become generally accepted as a norm, they are referred to be axioms and, in certain cases, universal laws.

The famous examples of a completely theoretical 'thought' experiment are Schrodinger's cat (quantum physics) and time dilation (relativity). Some of such sub-fields of physics have theories that cannot be proven with real-time experiments yet. Although theoretical physics is a sub-branch of physics, every branch of physics has theoretical and experimental parts. In some branches of physics, a single scientist or a group takes care of data collection, analysis, and construction of a new theory. But fields like cosmology and particle physics, each individual has to decide on whether they want o pursue the theoretical or experimental aspect of it. Those who want to pursue this as a career should be extremely well-versed in mathematics, programming, simulations, statistics, and also data analysis.