Kal
“I go into the Upanishads to ask questions.” — Laureate Niels Bohr, Noble Prize winner Physicist

There is no perfect English word for the Indian word “Kal”. Dictionary shows “tomorrow”. However, grossly it also stands for “yesterday”. A more refined definition could be “time” — for the derivations from kal are all related to time — “mahakal”, “ihakal”, “parakal”, “trikal”, etc. are most Sanskrit words or derived from Sanskrit but has no relevant English definition.
For generations, yogis or the rationalists, scientists or philosophers, has been seeking the essential questions related to time. The data driven cosmic laws based on scientific calculations and experiments surprisingly seem to merge in many areas with the yogic flow of thoughts, theories and assumptions.
In the early 1900, Quantum Physics first unified space with time ruling out age-long (about 300 years old) theory of Newton that “Time is an absolute”. Modern research shows that Universes are being created all the time and created from nothing.
However, about 5300 years back, the Hindu cosmology already had this conception about space and time — there is no absolute start to time, as it is considered infinite and cyclic. Similarly, the space and universe has neither start nor end, rather it is cyclical.
The fundamentals of space, time, energy and universe as conceived by the yogis many long years back was considered paradoxical. Many of those paradoxes are getting validated by science today, especially on time (kal) and space (lok). Stalwart scientists like Einstein, Nikola Tesla were followers of the Vedas and Upanishads.
The basic essence of yogic science is “finding yourself” and unless we practice to do that, all what we are seeking may only end up in “Maya”.