Does the universe have boundaries and what is its future?
At present, cosmology has developed into a relatively mature discipline. Through some detection methods, the accuracy of understanding the universe can reach the level of percentages, that is, accurate to two decimal places. It also means that we can understand the entire universe on the largest scale.
It is worth mentioning that the universes on the largest scales and the earliest universes are actually quite simple, and their main characteristics can be easily delineated with a few special parameters.
Our current understanding of the universe is essentially encapsulated in the so-called Standard Model of the Universe, which closely matches our observations of the universe. In addition, the model of the universe is not only verifiable, it can also be used to make predictions about the future of the universe. Of course, if necessary, we can also delete or add content to it.
At the same time, the model crucially points out the composition of the universe: about 5% atomic matter (regular matter, such as human beings), about 25% dark matter, and the remaining 70% dark energy.
Lyman Page, an expert in observational cosmology, chair of the Department of Physics at Princeton University and author of “A Little History of the Universe,” said that we generally use the cosmic microwave background, a weak thermal radiation left over from the birth of the universe, as a clue to understand the universe.
For example, dark matter is inferred from its gravitational effects through the cosmic microwave background. Although humans have not yet detected it directly, and we are not sure if it can be detected, we know that dark matter must be there.
”It’s like one day you find your bag is heavy and you take all the books out and still can’t get the bag. Then there must be something else in there, you just have to keep ‘digging’ until you find it ,” added Page, “and we have ample evidence to justify the way the universe is understood through the cosmic microwave background.”
Page has been studying the cosmic microwave background for many years. He once won the Shaw Prize in Astronomy, known as the “Oriental Nobel Prize” for his “major achievements in unlocking the age of the universe”; he was also a member of the Wilkinson Microwave Anisotropy Detector experimental team, and Received the “Breakthrough Award in Fundamental Physics” in 2018. The team won the award for “drawing a detailed map of the early universe and upgrading human understanding of the evolution of the universe”. Heterosexual detectors are mainly used to accurately measure the age of the universe.
In describing what new knowledge of cosmology can be gained through the cosmic microwave background, he explained that it can be thought of as a “husk of light” around us, at the edge of the observable universe.
It is understood that the cosmic microwave background is similar to the thermal radiation of the sun or an electric furnace, but its temperature is extremely low, only 2.725K, which is only 2.725 degrees Celsius higher than absolute zero (0K, the lowest thermodynamic temperature), so it is also called “3K background” radiation”. This also reflects its ancient origin from the side, and its understanding can be said to be the foundation of the standard universe model.
The cosmic microwave background is continuing to provide mankind with various new insights into the universe. In addition, most of the information gleaned from it comes from temperature changes at different locations in the universe.
If an observer observes the Milky Way from a distance, the Milky Way in his eyes will look like the one shown in the image above, with an overall shape similar to a disk with a bulge in the middle.
Before we delve into the various properties of the cosmic microwave background and what information humans can obtain from it, we must first understand some basic concepts. In the basics section, there are two main clues, namely that the speed of light is constant and finite and the universe is expanding.
It is worth mentioning that in order to present the latest scientific research results to readers through books, a major difficulty is how to keep books at an appropriate reading difficulty.
In order to make his book “A Little History of the Universe” more straightforward to read, Page has made clear explanations of many terms and scientific concepts in the book. At the same time, the mathematical knowledge required to read the book is not complicated, “that is, the level of ‘distance = speed × time’,” he said.
Although the book is not long, only 150,000 words, it presents readers with relevant knowledge of the entire universe. The size, composition, geometry, evolution process, the physical laws used to describe the universe, and the frontiers of cosmology are all introduced in the book. In addition, the specific discovery process of this knowledge is also included. At its core, the book is about observations and interpretations of the universe, and points to how possible explanations have been falsified or expanded.
The book also weaves current observations of the universe into a unified picture of the universe through relevant physical representations.
Of course, the cosmic image shown in the book is only one of the many possibilities of the universe, but this image can explain the scientific observation data held by human beings with a minimum of assumptions, and will reveal this to the world in various subsequent observations. whether the image is correct or not.
At the same time, some unresolved problems in cosmology are listed at the end of the book for readers to analyze and discuss.
Cosmology is a fascinating scientific research “mecca”. In the field of experiment and theory, scientists are continuing to explore more deeply. It is also through the unremitting efforts of scientists that human beings can break through the limitations of the body and expand their vision to the world beyond the reach of the eyes, to the edge of the universe.