We really don’t understand time yet
By Paul Sutter | SPACE.com
We don’t understand the concept of time much at all.
Everyone experiences time — literally every day — but rigorous and comprehensive understanding of the topic is … lacking. Then again, we do know some things, especially when we look at time through the lens of special and general relativity. Einstein’s work taught us many things: that space and time are connected, that you can never travel faster than light, that our universe has a finite age and that different observers experience different lengths of time.
All these revelations lead to some interesting questions. It’s time (pun intended) for a roundup.
How old is the universe?
Our universe is 13.77 billion years old, according to our current best estimates, which are very good, thank you very much. But when special relativity is invoked, we also understand that everyone measures time differently, depending on their speed. We, on Earth, whizzing around the sun, with the sun spinning around the Milky Way, and the Milky Way blasting through the intergalactic vacuum, should have a different perspective on the flow of time than someone else on a different planet around a different sun in a different galaxy. That said, how can we possibly pin down a „real“ age of the universe?