How long is the universe?

1. How big is the universe? American scholars believe that the diameter is at least 78 billion light years.

The ripples in the residual background microwave radiation after BIGBANG reveal the size of the universe, which has attracted the attention of countless people: the two ends of the universe are at least 78 billion light years apart.

The research team led by Neil Cornish, a physicist at Montana State University, believes that their research at least partially answers one of the most basic questions in cosmology: How big is the universe?

Until now, the estimation of the size of the universe is between "as big as you see" and "infinite". In a word, there is no answer that most people agree with. It all depends on a model of the universe that you accidentally come up with. Cornish et al.' s research at least determines the lower limit of the size of the universe, and does not rule out the possibility that the universe is infinite.

According to Nature, some people think that the universe is like a football, with a diameter of 60 billion light years. According to other theories, the universe is not that big, just wrapped by itself, so it is difficult to determine the boundary. Cornish told Nature magazine, "In principle, the light of the earth moves around the universe, so if we see the situation of the earth 4 billion years ago, please don't make a fuss."

His research team then decided to look for the early conditions of the earth in the universe. But where should I look? The answer is as far as possible, which means they need to use WMAP detectors to analyze the cosmic background microwave radiation. In this way, the microwave radiation generated in the initial stage of the universe (379,000 years after the Big Bang) can be detected.

If the universe is small, the light from the same light source can reach the same position from different directions. The research team calculated that this would produce radiation irregularities (hot spots and cold spots). However, the research team found no cold spots and hot spots in the background microwave radiation. Cornish concluded that the universe is larger than our equipment can observe, with a diameter of at least 78 billion light years. The universe may be bigger, and he hopes to revise his calculation by further studying the results of WMPA. The smallest size of the universe may increase to 90 billion light years.

The universe is as big as the human heart. For a broad-minded person, the world is really vast. It is difficult for narrow-minded people to stand on their feet.

3. The word "universe" probably originated from Mozi, a famous philosopher in ancient China (about 468-376 BC). He used "Yu" to refer to the space in all directions, and "Zhou" to refer to the time from ancient times to the present. Together, it refers to everything in the world, no matter how big or small; Past, present or future; To approve or not to approve ... In short, everything is everything.

From a philosophical point of view. People think that the universe has no beginning, no end and no end. However, we are not going to discuss this abstruse concept in depth, so let's leave it to philosophers to study. We might as well squint and use our existing science and technology to talk about the universe that we can understand and observe. People call it "our universe" or "total galaxy".

According to the latest observation data, the farthest galaxy observed by people is 65.438+0.3 billion light years. That is to say, if a beam of light is emitted from the galaxy at a speed of 300,000 kilometers per second, it will take 654.38+03 billion years to reach the earth. This distance of 654.38+0.3 billion light years is the universe as we know it today. More specifically, the universe as we know it today, or its size, is a spherical space with the earth as the center and the distance of 65.438+0.3 billion light years as the radius. Of course, the earth is not really the center of the universe, and the universe is not necessarily a sphere. It's just limited to our current observation ability, and we can only know this extent.

In this spherical space with a radius of1300 million light years, there are about1250 million galaxies that have been discovered and observed, and each galaxy has hundreds to trillions of sun-like stars. So as long as you do a simple math problem, it is not difficult for you to know how many stars there are in the universe we have observed. In such a vast universe, the earth is really a drop in the ocean and insignificant.

4. How big is the universe known to mankind?

The universe contains all substances, including energy and radiation that humans have discovered, and everything that humans know and believe exists in space.

There are hundreds of millions of celestial bodies in the universe, which are combined with each other very skillfully and regularly. Most stars make up galaxies, such as our solar system. Galaxies form the Milky Way again. There are at least 65438+ million galaxies in the universe.

The space is very vast, and light can spread 300,000 kilometers in one second. In the Milky Way galaxy where our earth is alone, the width of the span is 65438+ million light years. There are 65438+ million galaxies in the universe, so how big is the universe? You still do the math.

In order to explain the scope of the universe, scientists have calculated that the volume of 654.38+0.3 million earths is only equivalent to the volume of the sun, and the number of stars equivalent to the sun can reach more than 200 billion in the Milky Way. If the universe is regarded as a big ball with a radius of 1 km, then the Milky Way is only as big as a pill and is located near the center of the ball.

In practical observation, people use high-powered radio telescopes to search for the quasar Sirius Giant 20 billion light years away. This is the farthest star that humans can really grasp at present, and it is also the largest range for people to understand the universe. Of course, it is not the actual edge of the universe. Because people's cognitive ability is limited