The stars in the sky can be said to be the earliest navigation of human beings. Before the invention of the compass, sailors on the sea relied on the stars to judge their direction.
Because the position of the stars seemed to never change in people's eyes at that time, so people thought the earth was the center of the universe, and all the stars moved around the earth, which gave rise to geocentric theory. Later, Copernicus proposed the heliocentric theory, but only changed the center of the universe from the earth to the sun.
Later, with the development of science and technology, scientists found that both the earth and the sun are just ordinary planets in the vast universe.
And the sun and the earth are not stationary, the sun with the whole solar system can rush 7 billion kilometers every year, the same is true of other stars in the universe, everything is in motion, only relatively static, no absolutely static matter 39bet-kết quả bóng đá-kết quả xổ số miền bắc-kèo bóng đá -soi cầu bóng đá-đặt cược.
The earth around the sun, the sun around the black hole at the center of the Milky Way galaxy, the Milky Way is around the greater structural movement, of which the earth's orbital speed of 29.8 km/s, but the earth no matter what, are still within the space of the solar system, like you walk around the plane, but still in the plane, movement is the plane with you truly, also is the sun.
The Sun orbits the center of the Milky Way at 220 kilometers per second, or 792,000 kilometers per hour, but the solar system is moving in a different direction than the Milky Way, with the galaxy moving at 550 kilometers per second toward the constellation Hydra.
Combining the speed of the Milky Way and the speed of the solar system, the scientists calculated that the sun moves at 370 kilometers per second, or 1.33 million kilometers per hour, compared to the cosmic microwave background radiation, or 32 million kilometers per day across the universe.
If the solar system is moving at a high speed, and so are other galaxies in the universe, why do the stars, when we look at them from Earth, remain almost exactly the same for thousands of years?
In ancient times, people found that the position of the stars did not change for hundreds of years, so they were called stars. The "Gan Shi Xing Jing" in the Warring States period recorded the shape of the Big Dipper like a spoon. After more than 2,000 years, why did its position not change?
The stars seen from the Earth can be divided into two kinds, one is the celestial bodies in the solar system, and the other is the celestial bodies outside the solar system. The celestial bodies in the solar system, such as the sun, can be observed very clearly because of the movement of the earth, the position of the sun changes within a day.
The location of the other planets in the sky also can cause obvious change over time, such as Mars can sometimes be very far from the sun, but sometimes will disappear, but we can see the stars in the vast majority come from outside our solar system, solar system's planets visible to the naked eye only basic water and five planets, Neptune and Uranus because generally cannot detect distance too far away.
So are stars outside our solar system stationary?
The answer is no, the objects we can see from the Earth outside the solar system are stars, like the sun. They are moving very fast, and we know that the motion has a direction and an arrow, and the motion of the star is simply broken down into two direction components, namely the radial velocity and the tangential velocity.
The radial velocity can be understood as the component of the star along the observer's line of sight to the star, which tells us whether the star is moving away from the Earth or moving closer to the Earth.
Tangential velocity refers to the component perpendicular to the observer's line of sight. It shows the change of the star's position on the celestial sphere. This change is projected on the celestial sphere as "self", which is the change of the star visible to our eyes.
Most visible to the naked eye, scientists have found night star to less than 0.1 seconds per year, and this is not a time of seconds seconds, but measuring Angle of seconds, one second is equal to the one in 3600 once, or 3600 seconds to equal to move once in the sky, the stars at night to basic every year is less than 0.1 seconds, which means that the obvious change to see them, It takes at least 36,000 years.
This is mainly because the stars that can be seen are so far away from us and lack obvious reference points that their positions in the night sky are relatively fixed, and even a major shift in the position of our nearest star, Proxima Centauri, seems to have shifted just a little.
The only way to see their position change in time is with a high-precision telescope.
Therefore, the stars in the sky are not stationary, but the time of human existence is too short, these stars are too far away from the earth, and the speed of change is too slow, so that we can not observe the changes of stars, resulting in the illusion that the stars in the night sky seem to be fixed.
In the big dipper, for example, scientists according to the moving speed and direction, each star roughly describes the appearance of it in one hundred thousand and after hundreds of years ago, and now is completely two shapes, after hundreds of years ago, the primitive and one hundred thousand for the future of the people, and we see the big dipper is very different, that is to say, we see every day the stars are not the same.