"Mysterious Starry Sky" PPT courseware

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"Mysterious Starry Sky" PPT courseware

Part One: The Milky Way

The Milky Way is the star system in which the solar system is located, including 120 billion stars and a large number of star clusters, nebulae, as well as various types of interstellar gas and interstellar dust. It has a diameter of about 100,000 light-years, a central thickness of about 12,000 light-years, and a total mass of 140 billion times the mass of the Sun. The Milky Way is a spiral galaxy with a spiral structure, that is, it has a galactic center and four spiral arms. The spiral arms are 4,500 light years apart. The sun is located in the Orion Arm, an arm of the Milky Way, about 26,000 light-years away from the center of the Milky Way.

discovery process

Scientists discovered that the Milky Way has gone through a long process. After the invention of the telescope, Galileo first used a telescope to observe the Milky Way and discovered that the Milky Way is composed of stars. Later, Wright, Kant, Lambert and others believed that the Milky Way and all stars might be integrated into a huge star system.

Introduction to the Milky Way

Most stars in the Milky Way are concentrated in an oblate spheroid of space, shaped like a discus. The protruding part in the middle of the oblate spheroid is called the "nuclear bulge", with a radius of about 7,000 light-years. The middle part of the nuclear ball is called the "silver core" and the surrounding area is called the "silver plate". There is a larger sphere outside the galactic disk, where there are few stars and low density, called the "galactic halo", with a diameter of 70,000 light-years.

Mysterious Starry Sky PPT, Part 2: Light Years

In astronomy, light-year is used as the unit of distance to express the distance between celestial bodies. In space, light travels at a speed of 300,000 kilometers per second. One light year is the distance traveled by light in one year, which is approximately 9.5 trillion kilometers.

How long does it take to travel a distance of 70,000 light years?

1. If you take a train with a speed of 120 kilometers per hour, you need ( );

2. If you take a plane with a speed of 800 kilometers per hour, you need ( );

3. If you ride on a rocket with a speed of 40,000 kilometers per hour, you need ( ).

Altair is 16 light-years away from the earth, Vega is 26 light-years away from the earth, and Altair and Vega are 16.4 light-years apart. The speed of radio waves is as fast as light. If Altair makes a wireless call to Vega, it will take nearly 33 years for a call back.

The circumference of the earth is about 40,000 kilometers, 1 light year is about 10 trillion kilometers, and it can circle the earth 250 million times. The Milky Way is about 70,000 light-years in diameter and can orbit the Earth 17.5 trillion times.

Mysterious Starry Sky PPT, Part 3: Extragalactic Galaxy

Using the most advanced astronomical telescopes, we can see galaxies tens of billions of light years away from us. More than a billion extragalactic galaxies as large as the Milky Way have been discovered.

Extragalactic galaxies are divided into: elliptical galaxies, spiral galaxies, lenticular galaxies and irregular galaxies.

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"Mysterious Starry Sky" PPT:

"Mysterious Starry Sky" PPT Part One Content: Review The composition of the solar system: the sun, eight planets, 66 satellites, 1 dwarf planet, and small celestial bodies. On a clear night, we can see a white light band like light clouds and mist dotted with stars in the sky. It...

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Update Time: 2024-09-25

This template belongs to science courseware Qingdao Edition Fifth Grade Science Volume 2 industry PPT template

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