Does the universe hold onto its past, or do moments simply disappear once they occur?
In this segment of Cosmically Curious, host Patrick McNameeKing speaks with astronomer John Gianforte from the University of New Hampshire about whether the cosmos preserves a record of everything that has ever happened — and what the physics of our own sun reveals about the vastness of that question.
Transcript:
Patrick McNameeKing: Recently, a listener wrote in asking: "Does the universe keep a record of everything that has ever happened? Or are moments like our lives truly lost forever?"
John, what do you think?
John Gianforte: It's a great question because it really begs an answer.
But the truth is, nobody really knows, right? The protons and electrons and neutrons that make up those various atoms that are parts of molecules that make up what you are . . . those weren't always "Patrick." Those were, you know, something else in a bygone era.
Just think, the sun is losing 4 million tons of mass every second. The sun converts, you know, 467 million tons of hydrogen into helium every second. So the sun is lighter and lighter every second by an amazing amount. We're lucky the sun has lots of mass, right?
So it substantially has all of the constituents that it did when it first formed, even though these fusion reactions were taking place since the sun formed 4.6 billion years ago.
It's hard for me to imagine being able to replicate or understand all of what happened in just our own star alone, let alone the formation of a multitude of stars, or the formation of the Milky Way galaxy some 13 billion years ago. I guess I'm saying my mind is too small to comprehend that. I guess I have to admit that I'm just beating around the bush.
Patrick McNameeKing: Well, John, we appreciate you beating around the bush for us.
If you have questions about the night sky, send us an email, cosmic@nhpr.org.
