Observation of Magellanic Cloud

The large Magellanic Cloud is about180,000 light years away from us, and the small Magellanic Cloud is also 2 10/0,000 light years away. The bright star on the lower left is Alpha Seniors, a resident of the Milky Way, only 365,438+00 light years away. Barley clouds are all in the southern hemisphere, about 20 degrees from the south celestial pole. Barley Cloud is located at the junction of two constellations, Swordfish and Mountain Constellation. It spans two constellations and covers an area of 8× 7, which is equivalent to the visible area of more than 200 full moons. Maiyun is located in the constellation Rhododendron, occupying a sky area of 4× 2, which is equivalent to the visible area of 30 full moons. The distance between barley cloud and wheat cloud is about 20. Look at the barley cloud in the southern hemisphere, which hangs high near the southern zenith all year round, competing to shine and never falling below the horizon. Just as we watch the Big Dipper in the northern hemisphere, it will never fall below the horizon. They are a pair of treasures in Nantian. Unfortunately, it can't be seen in most parts of the northern hemisphere. It can only be found in Nansha Islands, China, which is very close to the southern horizon.

Magellanic Cloud belongs to a small and irregular galaxy, which is the satellite galaxies of the Milky Way. It orbits the Milky Way once every 65.438+0.5 billion years. Because there is no standard fixed shape, Magellanic Cloud has become the most controversial and even the most exciting celestial body in the southern hemisphere. Some astronomers say that the Magellanic Cloud seems to interact with dark matter in the universe, forming a galaxy bend.

What is galaxy bending? I find this difficult to explain. Simply put, the operation of nearby nebulae may have an impact on the Milky Way where we live. Just like the agitation at the other end of the carpet, it can cause wavy shape distortion. At present, the silver plate of the Milky Way has become a bowl.

The most famous celestial bodies in the southern hemisphere, except the rosy keyhole nebula and the shining Southern Cross, belong to the Large Magellanic Cloud. These two celestial bodies are invisible at the latitude of Chinese mainland. They are the satellite galaxies of our own galaxy, and M32 and NGC205 next to Andromeda galaxy (M3 1) are small galaxies. LMC is 65,438+0.6 million light years away from the Earth, and SMC is 65,438+0.9 million light years away from the Earth.

German amateur astronomers mistook LMC and SMC for two "clouds" in the sky when they came to Australia to watch the stars. Why can't the wind blow away? For a while, it was a joke. NGC 104 next to SMC is another good viewing target, and the Tarantula Nebula next to LMC should not be missed.

The Magellanic Cloud, like our Milky Way, also contains gas and stars. Barley Cloud is a dwarf or irregular galaxy with a mass of 1/20 that of the Milky Way. Maiyun belongs to an irregular galaxy or an irregular rod-spinning dwarf galaxy, and its mass is only1100 of that of the Milky Way. The Magellanic Cloud is rich in gas. The mass of neutral hydrogen accounts for 9% and 32% of their total mass respectively, which is much larger than that of the Milky Way. This shows that their evolution is not as high as that of the Milky Way. Their interstellar dust content is less than that in the Milky Way, and the young constellation I has many celestial bodies and a large number of high-luminosity O-B stars. In addition, new stars, supernova remnants, X-ray binaries and other celestial bodies have been observed. For example, a supernova (SN 1987A) in large magellanic cloud was discovered on February 23rd, 1987. Its maximum brightness is 250 million times that of the sun, and it is considered as the brightest supernova in 383 years. The Magellanic Cloud orbits the Milky Way once every/kloc-0.5 billion years. Every time we approach the Milky Way, its stars and gases will change under the gravitational force of the Milky Way. Small magellanic cloud has now been torn apart, and its star will become a part of the Milky Way. Large magellanic cloud will end up with the same fate.

The Magellanic Cloud and small magellanic cloud are the closest neighbors of the Milky Way. For hundreds of years, these two nebulae have been considered as companion galaxies of the Milky Way. But the latest research by Gurtina Besla, an astrophysicist at Harvard University, and her colleagues shows that the Magellanic Cloud has only recently arrived and is the first visitor to the Milky Way.

These two nebulae are not only irregular in shape, but also like volcanic cloud. Among them, the Large Magellanic Cloud is 160000 light years away from the Earth, and its diameter is about 1/20 of that of the Milky Way. The small Magellanic Cloud is 200,000 light years away from the Earth, only a few percent the size of the Milky Way.

Many years ago, astronauts claimed that the three-dimensional velocity field of Magellanic Cloud passing through the Milky Way was much larger than before. There are two explanations for this phenomenon: 1) The Milky Way is much bigger than before; 2) The Magellanic Cloud is not constrained by the gravitational field of the Milky Way. However, further research by Besla and his colleagues confirmed the second view, claiming that the Magellanic Cloud crossed the Milky Way for the first time.

However, such an observation still has commercial considerations. Because if the Milky Way is taken as the datum, its warping depth can reach up and down 10000 light years. But these two nebulae only visited once in 10 or 3 billion years ago, so their gravity tides can't cause such warping. Faced with this situation, Besla said, "We still have many unsolved mysteries. When an answer appears, there may be more questions. "