Einstein's General relativity By @immortal.space Nov,08,2021 Einstein's General Relativity relates the curvature of space to what is present inside of it, but the equation has infinite variations.   One very general class of spacetimes, however, obeys the same straightforward equation: the Friedmann equation.   Just by measuring the universe today, we can extrapolate all the way back to the Big Bang, 13.8 billion years in our past. In all of science, it’s very easy to reach a conclusion ba...

Calendars By Ashish singh Nov,08,2021 Calendars – whether stone, paper or electronic – have been used for millenniaA calendar is a system for organizing days and specifying dates, as well as the physical device (whether paper or electronic) used to record such a system. Calendars have historically been designed for social, religious, agricultural, commercial or administrative purposes (or a combination of all of these). A calendar can also be extended into the future and used as a reminder...

Measurement of Time By Ashish singh Nov,08,2021 Watches are just one of many possible instruments of time measurementTime provides us with a measure of change by putting dates on moments, fixing the durations of events, and specifying which events happen before which other events. In order to do that, some method of time measurement is needed. The science or art of the accurate measurement of time is known as chronometry (or, less formally, timekeeping). A similar concept, horology, usuall...