# How do we know if the Universe is flat or not? #shorts

## Метаданные

- **Канал:** Dr. Becky
- **YouTube:** https://www.youtube.com/watch?v=Snnorbt9wsw
- **Дата:** 01.05.2026
- **Длительность:** 1:49
- **Просмотры:** 11,629
- **Источник:** https://ekstraktznaniy.ru/video/48961

## Описание

The geometry of the universe is a direct fingerprint of the physics that shaped it in the very first moments after the Big Bang. Specifically, it's a test of something known as inflation, an unimaginable burst of expansion in the Universe's first fraction of a second of its life, which took something smaller than an atom and stretched it to the size of a melon in less time than it takes light to cross a single proton. If inflation happened, like our best model of the Universe predicts it did, then that expansion should have stretched the Universe flat. It should have given the universe a flat geometry.

Inflation underpins our explanation for why the universe looks the same in every direction, why it's so smooth, and why structure formed the way it did. So our best model of the Universe is just one big house of cards with inflation of the things propping it up. Take inflation away and everything unravels. This is why cosmologists care so much about whether the Universe’s is flat or not

## Транскрипт

### Segment 1 (00:00 - 01:00) []

This is why cosmologists care so much about whether the universe is flat or not. The geometry of the universe is like a direct fingerprint for the physics that shaped the universe in the very first few fractions of a second of its lifetime. Specifically, it's a test of something known as inflation. an unimaginable burst of expansion which took something the size of an atom and stretched it out to the size of a melon in less time than it takes light to cross a single proton. If inflation happened like our best model of the universe predicts it did, then that inflated expansion should have stretched the universe flat. It should have given the universe a flat geometry. And inflation underpins our explanation for why the universe looks the same in every direction that we look in. why matter is so evenly distributed and why structure formed the way that it did. So our best model of the universe is just one big house of cards with inflation being one of the things at the bottom propping it all up. Take inflation away and everything comes crumbling down. Now thankfully there is a number that describes the geometry of the universe that we actually have a hope of measuring and it's represented by the Greek letter omega. And that number is at the heart of the entirety of cosmology. It's technically a measure of the energy density of the entire universe. But the maths is set up so that if omega equals exactly one, it means the geometry of space is flat. But if omega is greater than one, space curves back in on itself and the universe has a closed curved geometry. If omega is less than one, it's got that Pringlelike geometry, aka an open universe. So, how do we know if omega is one or not?