Being curious, humans in ancient times would often look up at the stars and wonder what the outside world would be like.
Before science and technology came into the human world, most people thought that the earth was the center of the universe, the head of the stars and the sun are part of the earth. We now know that relative Yu Haohan universe, earth and human beings are small like dust, how small it is, we are always difficult to have a clear cognition, but some intuitive data can help us understand.
In 1972, the Apollo 17 lunar module, this is the final mission of Apollo. On the way to the moon, the astronauts 60 miles (29000 kilometers) from earth took the famous photo: blue marbles, and this is a panorama of the earth, the universe of a dark background, quietly hung in the air a blue planet 39bet-đua chó-game giải trí -đá gà-đá gà trực tuyến-đánh bài.
Before this, Apollo 8 also photographed the planet's panorama, and blue marbles. The earth was shot on the surface of the moon. The moon is the nearest to the earth a celestial body, only 380000 kilometers. It may be far away from the distance on the earth, but under the background of the universe is almost negligible.
Watching Earthrise from the moon, this blue planet is so beautiful, but it also seems a little fragile.
Leave the moon and head deeper into space
We'll meet Voyager One, which has been flying for 44 years. Voyager One was the first interstellar probe in human history and made great contributions to mankind. Although many other probes have been launched since then, only Voyager One has made it the farthest.
On February 24, 1990, Voyager 1 had completed its primary mission to explore the wider reaches of interstellar space, and astronomer Carl Schaefer. At Sagan's suggestion, Voyager 1 looked back from 6.4 billion kilometers from Earth and snapped a series of photos of the inner solar system, forming a solar family portrait.
With a photo that is particularly famous, it was named the "pale blue dot", standing in the photographer's point of view. There is no doubt that this photo is a failure. Most of the area is dark. There are several interference stripes, but when we magnify the photo, you can find a hidden in the middle of the chromatic stripe some dim blue light.
Taking up just 0.12 pixels of the picture, this light almost merges with the noise, but it is actually our home: the Earth we live on, and the image has allowed millions of people with busy lives to take a peek out into space and think about what people and Earth mean in the universe.
This picture gives us a sense of the Earth's smallness in the universe, but the reality is much bigger than we think.
Because this picture is only 6.4 billion kilometers from Earth, and Voyager 1 continued to fly for 31 years after taking this picture, it still has not flown out of the solar system, and a conservative estimate is that it will take at least 30,000 years for Voyager 1 to completely fly out of the solar system and reach interstellar space.
And the solar system is very small. Although the diameter of the solar system has reached the LiangGuang years, it is almost insurmountable distance for humans, but when we stand in the Angle of the Milky Way, you will find the diameter of the Milky Way galaxy 180000 light-years across, stars like our sun is about 100 billion to about 400 billion, countless planets.
A distance that seems insurmountable to humans is only a billionth the size of the Milky Way.
When we look beyond the Milky Way again, we see that the Milky Way is actually quite small. The Milky Way, along with a dozen other galaxies like Andromeda, is part of the Local Group of galaxies. It's 10 million light-years across, and what we think of as the vast Milky Way is not even the largest galaxy in the Local Group.
Going further into the universe, we find that the local group of galaxies is not very large either. The solar system is the Milky Way, and the Milky Way is the parent of the Local Group of galaxies, which also has its parent: the Virgo Cluster, which is made up of our local group and more than a thousand other nearby groups of galaxies of the same class.
In shape, it looks like an irregularly shaped pancake that covers an area 110 million light years in diameter.
Later we found that our virgo cluster of galaxies, in the vast to some terrorist rania KaiYaChao clusters, rania KaiYaChao cluster diameter is about 5.2 light years, which includes nearly thousands of galaxies like the Milky Way. It looks like a light feather appearance, but in fact its quality has reached 10 ^ 17 times the mass of our sun.
The Ranja Kaia supercluster is not yet the largest known cosmic structure. The largest known cosmic structure is the Sloan Wall, which is 1.37 billion light years across. There may be even larger structures that have yet to be discovered, but beyond them lies the upper limit of human observation: the observable universe.
Theoretically, the most visible part of the universe is 93 billion light-years across, but the observable universe isn't the whole picture. Space at the edge of the universe is expanding faster than the speed of light, and that light will never make it to Earth, and we'll never see it.