The blue earth is the cradle of human civilization, carrying hundreds of millions of lives and countless stories, but when we look up at the starry sky, we will find that we are just a speck of dust in the universe.
Next, I will take you on an amazing journey from Earth, through the solar system, across the Milky Way, to the edge of the universe, to explore the mysteries of the universe and the place of humanity in it.
The Moon is about 384,000 kilometers from Earth, a shocking distance that would take more than 160 days to reach by car at 100 kilometers per hour.
Leaving the moon, our next stop is the Sun
The Sun is about 1At 500 million kilometers, it takes 8 minutes and 20 seconds for its light to travel to the Earth, which is unimaginable for us, but this is only a small distance within the solar system, and although the sun provides the energy needed for life on Earth, it is only one of the hundreds of billions of stars in the Milky Way.
As we continue to explore, we will encounter other planets in the solar system, such as Mars, Jupiter, and Saturn, as well as Pluto, which is located at the edge of the solar system, and even if we leave Pluto's orbit, it is still only within the solar system, because astronomers believe that the solar system is a spherical space-time with a radius of 1 light yearPluto's orbit is only the inner space of the solar system, and beyond it there are Kuiper belts and Oort clouds.
And after leaving the solar system, we enter the confines of the Milky Way
The Milky Way is about 180,000 light-years in diameter and contains hundreds of billions of stars, of which the Earth and the Sun are just a fraction. Almost every star we can observe belongs to the Milky Way, and every star carries at least one planet, so the number of planets in the entire galaxy may reach trillions, and there may be thousands of planets similar to the Earth, all of which may have unknown life forms.
The Milky Way is just one of the local galaxy clusters, which contain more than 50 galaxies spanning about 10 million light-years, and are part of the Virgo Supercluster, which contains thousands of galaxies and shows the spectacle of the accumulation of matter in the universe.
Above it is the SuperclusterLaniakeak SuperclusterIt is a huge group of galaxies that includes the Virgo Supercluster, covering more than 5 million light-years of space, where galaxies are gravitationally connected to each other to form part of the cosmic web.
Eventually, we reached the edge of the observable universe, about 93 billion light-years in diameter, which is the farthest distance that can be observed based on the speed of light and the age of the universe. But the real universe may be much beyond that, but our existing technology cannot detect much farther away.
Even in some cosmological theories, many people believe that our universe is a bounded and boundless closed four-dimensional supersphere, so that when it does not exceed the speed of light, our universe is actually boundless, and it will always return to the original point after a long enough time from one direction.
Regardless of whether there is an end or boundary in the universe, it is the whole of human civilization, all our science and technology and ideas are born and developed in the universe, maybe one day we can meet other intelligent civilizations in the universe, and then the mutual exchange between two or even more civilizations may be able to completely solve the mystery of the universe.
Scientific rambling