13.7 billion light years away, how far is the boundary of the universe from the earth?

The word "universe" was born in China a long time ago. Some ancient poems mentioned that the universe is the general name of time and space. Now, the word "universe" often emphasizes the sum of all galaxies in the space we live in, or the sum of the material space we know, which includes all the matter we know and understand.

Image source: Pixabay

Since ancient times, people have been trying to solve the question of how big the universe is. Throughout history, philosophers, thinkers or religions have put forward their own views on the size of the universe. Zhang Heng (78-139 AD), a famous astronomer in the Eastern Han Dynasty, put forward the idea of ​​"the universe is infinite and the universe is endless" in "Ling Xian".

With the progress of science and the development of technology, people are gradually using more and more advanced scientific instruments to understand the size of the universe. According to the data that humans can currently observe, the distance from the boundary of the visible universe to the earth is greater than 13.7 billion light years.

13.7 billion light-years, or the distance it would take for light to travel 13.7 billion years at the speed of light, is a huge and unimaginable distance! The deepest optical image we have obtained so far is the famous "Hubble Extreme Deep Field".

This is a small area in the southern sky taken by the Hubble Space Telescope. Each bright spot in it is a galaxy containing tens of billions of stars. These galaxies are what they looked like when the universe was just 500 million years old, which also means that what we see is what they looked like 13.2 billion years ago.

Source: Chongqing Industry-University-Research Cooperation Promotion Association

Author: Yuan Wei, principal of Chongqing Dazu District Experimental Primary School, senior middle school teacher

Review expert: Mao Yi, chief expert of Chongqing Science Communication Expert Group, professor of Chongqing Electronic Engineering Vocational College

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