Hong kong Xingcheng galaxy photography

When you look up at the beautiful starry sky, have you ever imagined its complete appearance? With the continuous development of space science and technology, we can see the earth from the perspective of the moon, and we can also see the "portraits" of the planets in the solar system. Satellites, aircraft carriers and space stations, we seem to know more about space, and have more expectations for the dream trip of "the sea of stars".

However, we can only walk in the solar system now, and we know little about galaxies outside the solar system. In this beautiful galaxy with 200 billion or more stars, the solar system is just a very ordinary and simple galaxy. Galaxy, under this romantic name, is full of puzzles and many unknowns, and it is difficult for us to recognize its "true face" in it.

At present, no one has seen the whole picture of the Milky Way with his own eyes, and the photos of the Milky Way circulating on the Internet are all imaginary. So far, there is only one real 360-degree panorama of the Milky Way.

The only panoramic view of the galaxy

You must have seen many pictures of the Milky Way. In the photo, the Milky Way seems to have come from ancient times, shining brightly and looking romantic and eternal. But I must disillusion you, because those are not real photos of the Milky Way.

So far, the only panoramic view of the Milky Way starlight comes from a space telescope called Spitzer. It belongs to the national aeronautics and space administration of the United States, and the only starlight panorama we have is composed of more than 2 million infrared snapshots taken in 10. For this panoramic photo, Robert Hurt, an imaging expert at NASA's Spitzer Space Science Center, said: "If we really print it, we will need a billboard the size of a sports field to show it."

Humans have spent more than ten years studying things from asteroids in the solar system to the farthest galaxies on the edge of Hubble's volume. During this period, Spitzer spent a total of 465,438+042 hours and 65,438+072 days photographing the disks or planes of the Milky Way galaxy under infrared light. Scientists in the United States have spliced more than 2 million infrared photos he took into a large field of vision. Spitzer photographed about 3% of the space of the Milky Way, but this photo only shows more than half of the stars in the Milky Way because it focuses on the earth belt on the plane of the Milky Way.

When we look at the center of the Milky Way from the solar system, we can see a crowded, dusty and star-filled area. The amount of dust increases with the increase of distance, thus blocking the visible starlight, and it can be seen that the telescope cannot penetrate into this area. Fortunately, infrared light can pass through the dust and let Spitzer scan to the center of the Milky Way, which gives us a chance to see the true face of the Milky Way.

About the shooting of the milky way galaxy

All the stars we can see belong to the Milky Way without exception, and the stars we can see are just the tip of the iceberg of the Milky Way. For thousands of years, human beings have looked up at the night sky and feared the Milky Way. Today, astronomers continue this tradition and continue to explore the sky.

When the weather is clear and cloudless, from the earth's point of view, the Milky Way in the night sky can only be seen in a very dark place, but we can't see it under the bright city lights. It looks like a long silver river flowing in the sky, so we call it "the Milky Way". You may ask, if you can see the Milky Way, why is it so difficult to take a panoramic view of the Milky Way?

First of all, the size of our galaxy is amazing. NASA estimates that the diameter of the Milky Way is between 65438+ million and 120000 light years. In order to get a panoramic view of the Milky Way, we first need a camera that can work in space, which can provide us with a broad field of vision. Then we need to fly the camera about 654.38+ million light-years above the Milky Way and aim it at the Earth-with our current propulsion technology, it will take 2.2 billion years to complete.

With the current level of human science and technology, the aircraft we make can fly the farthest place, which is not affected by the solar wind after flying out of the heliosphere. It is an interstellar space between stars, and we have not been able to build an aircraft that can completely get rid of the sun's gravity.

After 1923, scientists observed our Milky Way through different wavelengths (namely, radio waves, infrared rays, X rays and gamma rays), which enabled us to obtain images closer to the Milky Way itself. Unfortunately, astronomers can only see the Milky Way in this way, accounting for about 10% of the whole Milky Way, and what is on the other side of 10% is basically a mystery.

Although we have made a lot of efforts to see the Milky Way, we are still limited by difficulties such as perspective, scale and visibility obstacles.

"Portrait" of the Milky Way

What exactly is the Milky Way like? Early astronomers thought that the Milky Way was a spiral galaxy, much like the nearby Andromeda galaxy. There were many discussions about the specific shape of the Milky Way as a spiral galaxy, but the specific shape has been controversial. Some scientists believe that the Milky Way is more like a rod-shaped spiral with fragmented spurs and smaller arm structures.

It was not until the 20th century that the astronomer Harlow shapley measured the distribution and location of globular clusters that astronomers were able to accurately describe what our Milky Way actually looked like, and determined that the center of the Milky Way was 28,000 light years away from the Earth, and the center was a bulge rather than a flat area. In 2005, the Spitzer Space Telescope confirmed that the Milky Way is actually a rod-shaped spiral galaxy, not an ordinary spiral galaxy, which brings us one step closer to the true face of the Milky Way.

Our galaxy is surrounded by a halo, and hundreds of ancient globular clusters gather around the extended halo. The spiral arms contain stars, cold molecular gases, luminous star-forming regions and dark dust. The bulge of the galaxy mainly contains older stars and looks redder than the spiral arms. Because the central bulge is elongated, the Milky Way galaxy is classified as a rod-spinning galaxy.

Our sun is tied to the spiral arm of the Milky Way. If you can fly into space and look down into our galaxy, you will see a huge spiral, a bit like a windmill.

label

Facing the vast galaxy, I deeply feel the smallness of human beings. Time is not old, but human beings have changed from generation to generation. From the ancient "the Goddess Chang'e flying to the moon" to the modern spacecraft "flying to the moon for nine days", we are all marching forward with awe and exploring the unknown universe. It's a long way to the Milky Way. I believe that one day, we will see the true face of the Milky Way.