Nagoya City Science Museum

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Exhibition Guide


Purpose of Exhibition

Astronomical phenomena and celestial objects are displayed on the perimeter of this exhibition room. Walking clockwise alonge the wall, we can travel through the scale of the universe starting from size of the Earth to the edge of the universe. This scale is based on the notion of \"Powers of Ten\", making the lengths of each step you take 10 times longer then the last one.
The next world beyond the Earth, the solar system and stars is the world of galaxies. We show on large display various images of galaxies such as the Milky Way, the Andromeda Galaxy, the galactic system, some kinds of galaxies, an active galactic nucleus, the group of galaxies, the cluster of galaxies, and more.

Additional Knowledge

[Hierarchical Structure of the Universe]\\
Eight planets including the Earth rotate around the Sun and make up the solar system, along with minor planets, comets and trans-Neptunian objects.
Stars, that shine themselves like the sun, can be gathered together and some of them become open clusters or globular clusters. The galaxy consist of several billions to hundreds of billions of stars including these star clusters. They exist individually or in groups.
Group of galaxies: From several to dozens of galaxies gathered in a diameter range of about 150 million light-years.
Cluster of galaxies: A group of more than 50 galaxies gathered in a range of tens of millions of light-years.
Supercluster of galaxies: A larger group of cluster of galaxies.
In addition in the case of superclusters, if they form a larger structure with more than 10.000 galaxies in a range of 15 millions light years, this structure is called the great wall.

Galaxies are not uniformly distributed and there are \"areas with higher density of galaxies\" and \"areas with fewer galaxies\". The structure lookes like a piled up bubble. This means that the galaxy exists in the thin film of bubbles corresponding to the Great Wall, and it hardly exists inside of bubble (called Voids). This is called the Bubble universe theory or Large-scale structure. One bubble can have a huge diameter from 150 million to 200 million light-years.
It is thought that, such hierarchical structures were made from the density fluctuation in the early universe.

【 References 】

Article by Astronomy Section


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