In the time that human beings have explored the universe, every step has been accumulated step by step by the hard work of countless people, and it can be said that it has endured for a long time. This point, slowly Hua Feng also has a deep understanding.

2008—Recent research has shown that the Milky Way has only two main spiral arms, the Perseus spiral arm and the shield-centauri spiral arm, both of which are connected to the star rod at the center of the Milky Way's nuclear sphere. This realization comes from a photograph of the Milky Way taken by the Spitzer (Spitzer) infrared space telescope, released on June 3, 2008, which is the most detailed and largest ever taken by mankind

A 55-meter-long image of the Milky Way is 100 times higher than the clearest image ever taken. With the help of this image, scientists performed a star count of the Milky Way, and after the count, they concluded that the Milky Way had only two major spiral arms

。 On the full map of the Milky Way based on this study, one can see two main spiral arms originating from the nuclear sphere, with the Sun still located near the edge of the Milky Way, specifically on the inside of the Orion spiral arm, a small spiral arm between the Sagittarius arm and the Perseus arm. The centaur arm and the rectangular arm are mostly gas, with only a few stars dotted around.

On March 12, 2015, scientists discovered that the real Milky Way is 50% larger than previously thought.

Walk through the space:

In general, according to Einstein's special theory of relativity, the absolute velocity of any object as it passes through space is meaningless, because there is no suitable inertial frame of reference in space on which to measure the velocity of the Milky Way (the speed of motion, which always needs to be compared with another object to measure).

Because the cosmic microwave background radiation in all directions is very uniform, only a few ten-thousandths of a fluctuation. So George Smoot thought of a method, which is to measure whether the cosmic microwave background radiation has dipole anisotropy.

In 1977, George Smoot and others of the Lawrence Berkeley National Laboratory in the United States installed a microwave detector on the U-2 reconnaissance aircraft, and accurately measured the dipole anisotropy of the cosmic microwave background radiation, with a size of 3.5±0.6 mK, after conversion, the speed of the solar system in the universe is about 390±60 km/s, but this speed is opposite to the speed of the solar system around the Milky Way nucleus of 220 km/s, which represents the speed of the Milky Way nucleus in the universe, about 600 km/s.

In light of this, many astronomers believe that the Milky Way is moving at a speed of 600 km/s relative to nearby observed galaxies, with most estimates in the range of 130~1,000 km/s. If the Milky Way were indeed moving at 600 km/s, we would be moving 51.84 million kilometers per day, or 18.9 billion kilometers per year. The distance it travels each year is 4.5 times greater than the distance it traveled when the Earth was closest to Pluto.

the fourth cosmic velocity;

The so-called fourth cosmic velocity refers to the minimum initial velocity required for an object launched on the Earth to break free from the gravitational constraints of the Milky Way and fly out of the Milky Way, which is about 110-120km/s, which refers to the required sailing speed in most places in the Milky Way. However, if the linear velocity of the solar system and the linear velocity of the Earth are fully utilized, the minimum sailing speed can be reduced to 82 km/s.

What the future holds:

Current observations suggest that the Andromeda Galaxy (M31) is moving towards the Milky Way at a speed of 300 kilometers per second and could crash into the Milky Way in 30-4 billion years. But even if they do, the sun and other stars won't collide with each other, but it could take billions of years for the two galaxies to merge into elliptical galaxies.

Astronomers found that the Milky Way is "bigger than previously thought" According to a BBC report on the 6th, a research team composed of international astronomers found that the Milky Way, where the Earth is located, is larger than originally thought and moves faster.

Using observations from telescopes in Hawaii, the Caribbean and the northeastern United States, astronomers concluded that the Milky Way is rotating at 900,000 kilometers per hour, about 10 percent faster than previously estimated.

The Milky Way is also about 50% larger than previously thought.

Scientists note that the larger the volume, the greater the likelihood of a catastrophic collision with neighboring galaxies.

However, even if it happens, it will be 2-3 billion years away.

Researchers at the Harvard-Smithsonian Center for Astrophysics in the United States used the Ultra-Long Baseline Array (Ve

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ay) instrument to infer the mass and velocity of the Milky Way galaxy in which the Earth is located.

According to the researchers, the data found using this method is more accurate and requires fewer assumptions than previous methods.

The researchers also said that the Milky Way is similar to the Andromeda Galaxy (A

d

omeda Galaxy) is comparable in size.

The Andromeda Galaxy, the Milky Way, and the Triangular Galaxy are the three largest galaxies in the group of galaxies in which Earth is located.

Previously, scientists had always believed that the Andromeda Galaxy was the largest and that the Milky Way was just the "little sister" of the Andromeda Galaxy.

The researchers presented their findings at the 213th American Space Society meeting in California, USA.

Common observations in the Milky Way:

Mass ≈ 10E11 solar mass.

The diameter ≈ 100 kiloparsecs.

Silver core direction: α=17h42m.5, δ=-28°59′.

The Sun is 9,000 parsecs away from the galactic center ≈.

North silver pole: α=12h49m, δ=-27°2'.

The Milky Way rotates at a speed of ≈ 250 km/s at the Sun.

The rotation period of the Milky Way at the Sun ≈ 220E6 years.

The speed of movement relative to the 3K background ≈ 600 km/s.

(Orientation α=10h, δ=-20°)

NASA has released a digital version of the 360-degree panorama of the Milky Way, which is stitched together from 2 million photos taken by the Spitzer space telescope over the past 10 years, including more than half of the stars in the Milky Way, with 20 billion pixels.

People are amazed to find that the Milky Way is now as simple as a mouse click. In fact, this image shows only about 3% of the Earth's sky, but it contains more than half of the stars in the Milky Way.

The Spitzer space telescope, launched in 2003, has been studying from asteroids in the solar system to distant galaxies at the edge of the observable universe for more than 10 years. During this time, Spitzer worked for 4,142 hours to complete the recording of infrared images of the Milky Way. This is the first time that all the stars have been copied together on a single large panorama.

Our galaxy is a flat spiral, and the solar system is located on one of the spiral arms. When we look at the center of the galaxy, we always see a star-filled and dusty area. Because the large amount of dust and gas blocks visible light, the region near the center of the Milky Way cannot be directly observed with optical telescopes on Earth. And because infrared light has a longer wavelength than visible light, the infrared telescope Spitzer can penetrate dense dust and observe the heart of the Milky Way farther away.

Based on the data obtained, astronomers have drawn a more accurate map of the Milky Way's central belt and noted that the Milky Way is a little bigger than we previously thought. This data allows scientists to build a more comprehensive three-dimensional model of galaxies.

Scientists at Columbia University have made precise calculations of the mass of the Milky Way, and the latest results suggest that the Milky Way is about 210 billion times more massive than the Sun, including the cluster of stars with thousands of stars at the edge of the Milky Way.

Scientists have obtained a map of the mass distribution of the Milky Way through a supercomputer, and the mass of the Milky Way is the most accurate so far, and the results of this study will help us to study the structure of the Milky Way, such as the span of the Milky Way. Previously, our estimates of the mass of the Milky Way came from observing the speed at which the stars were moving, which had huge errors.

To arrive at this conclusion, the researchers proposed a new method to estimate the mass of the Milky Way, Ph.D. A from Columbia University

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Responsible for this study. The team believes that fluctuations due to the mass of the Milky Way can be observed through the Sloan Digital Sky Survey, and that Columbia University's supercomputer can simulate how much mass can induce fluctuations of this magnitude.

Of course, the rotation speed of the Milky Way and the position of different globular clusters should also be considered, which have a certain impact on the generation of fluctuations. In this way and combined with the Milky Way's diameter of about 120,000 light-years, scientists calculated that the mass of the Milky Way is 210 billion times the mass of the Sun.

Although this figure is a relatively accurate value as of 2015, there are still uncertainties, and the deviation may reach about 20%, which is much smaller than the previous mass estimate of the Milky Way.

Earlier data believed that the mass of the Milky Way was 750 billion times that of the Sun, and even reached 1 trillion times at one point, with an error rate of 100%, and it was almost impossible to determine the specific mass of the Milky Way. Although we have a further understanding of the mass of the Milky Way, scientists believe that this value is still not very accurate because the diameter of the Milky Way cannot be determined.

The calculations used a value of 120,000 light-years, but studies have shown that the true diameter of the Milky Way may be 1.8 million light-years, with some of the material overlapping with the Andromeda Galaxy.

There is still a lot of dark matter in the vicinity of the Milky Way that cannot be observed, and most stars are clustered within a radius of 40,000 light-years, and the rest is almost entirely dominated by dark matter, so there are many unobservable dark matter masses in the Milky Way. Scientists are using the Sloan Digital Sky Survey to make more precise positioning of stars within the Milky Way.

The size of the Milky Way should be at the midstream level in the universe, not too "heavy" and not too "thin", and the next step scientists plan to continue to study the mass of the Milky Way and compare it with other galaxies in the universe.

All this is just as Hua Feng originally expected, with a sense of history in the blandness, as if everything happened yesterday.