Eryn answers “In the first chapter, he mentions that the...”

Arun Cg asked this question about Astrophysics for People in a Hurry:

In the first chapter, he mentions that the universe is two light years across. And then later he says that two minutes have passed. The universe cannot be two light years across unless a year of time has passed, right? Is there something that I am missing?

Eryn They were talking about 2 minutes into the start of the universe. Like, in the beginning there was nothing, 2 minutes (later with all the stuff they w…moreThey were talking about 2 minutes into the start of the universe. Like, in the beginning there was nothing, 2 minutes (later with all the stuff they were explaining was happening) it was a few light years wide. A light year is measured in the time it takes for light from the sun to reach earth in a year I believer. Something like 10 trillion km. So at 2 minutes old, the universe was trillions of km wide, but continued to expand. (less)

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Wmba Dams Light gets to earth from Sun in 9 minutes.

A light year is how far something would travel in a year if it went at the speed of light.
Jul 02, 2021 02:16PM · flag

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Astrophysics for People in a Hurry

by Neil deGrasse Tyson (Goodreads Author)

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