20th Century- Scientists, the most curious and determined human beings in the world, are burning the midnight oil to create a unified quantum theory and the god equation, trying to find ways to unify the partial theories of quantum mechanics (for the microscopic) and the theory of relativity (for the macroscopic). They are in search of a completely deterministic model of the universe, where they know its cradle and determine its grave with unprecedented accuracy. They are nearly there- if they find the exact set of laws and conditions that govern the present universe precisely. For that, they need to examine and determine the behavior of some of the smallest particles in the universe. If they completely understand the behavior of particles in the present universe, they can accurately predict the behavior of such particles in the past and present using complex formulas, and ultimately, know the origin and fate of the universe altogether. And for that, they need to know the exact position of a given particle at a particular time AND its velocity or momentum. They are getting there, with refined theories, equations and observatory tools developing at light speed (metaphorically, of course!). And… they did it!... OH NO! They almost reached there, but The Uncertainty Principle happened! So… what is this principle that’s hampering our progress? Let’s delve into the world of… UNCERTAINTIES! The Uncertainty Principle states that the more precisely we study the position of a particle, the less precisely we can examine the momentum or velocity of the same particle and vice versa. Reason? To know the exact position of a particle, we can put a screen behind the particle’s approximate path area and point a beam of light at it. We can thereby find its position at a particular time based on the photons it scatters, visible on the screen behind. But, as the speed of particles is like, REALLY fast, you can measure its precise position at a given time only if you use a light with short wavelengths. All good till now, isn’t it? Well… it’s time for… determining the velocity of the same particle! Now, according to Planck’s quantum hypothesis, which states that energy (here, light) cannot be radiated off from an object at an arbitrary rate, but in certain packets of energy called quanta. And in these “packets” of energy, the shorter the wavelength of the energy waves, the higher the frequency, and, ultimately, more the energy of the quanta. Now, when we relate this to our situation, we can see that we can only point the beam of light at the particle in certain quanta. And as we have to use light of short wavelengths to accurately measure the position of the particle at a given time, its frequency would be high, and so will the energy of the quanta. This high energy, when pointed at the particle, can disturb its original velocity, momentum and pathway, making it impossible to know its original velocity. On the other hand, to measure the particle’s velocity with precision, one needs to use light with longer wavelengths to reduce the energy of the quanta and preserve the original velocity of the particle with accuracy. This, in turn, will reduce how accurately we measure the position of the same particle at a given time. Ultimately, how can we even predict the future or decipher the past of the universe if we can’t even determine the present behavior of things around us!? One thing’s for sure- we’ve got a LONG way to go before we make a perfect cosmic movie with a perfect beginning and a perfect end! But, scientists never put their hopes down, do they? That’s because science is all about trial and error, experimenting, observing, and verifying; so if something gives them a hard time, they try to find solutions! And one thing’s for sure- seeing the current rate of scientific and mathematical breakthroughs in cosmology, one day, we will find the solutions to our questions. Till then it’s me, Prisha Pateriya from Batch 30, zooming out of the microscopic world of uncertainties!
