" GALAXY "

*Introduction 
A galaxy is a group of stars, clouds of gas, and dust particles that move together through the universe. There are billions of galaxies in the universe. They probably formed billions of years ago, soon after the universe began.

The Sun, Earth, and the other planets of the solar system are part of the Milky Way galaxy. Most galaxies move through the universe as part of clusters, or groups, of galaxies. The Milky Way is at one end of a cluster called the Local Group. It includes about 40 galaxies. The largest galaxy in the Local Group is the Andromeda Galaxy.

*Size

Even the smaller galaxies are made up of millions of stars. These galaxies may be 5,000 light-years across. (A light-year is the distance light travels in a year—about 5.8 trillion miles, or 9.5 trillion kilometers.) The Milky Way is roughly 20 times larger than that. It includes hundreds of billions of stars. The largest galaxies are even more huge and contain trillions of Stars.

*Shape 

Galaxies are divided into three main categories based on their shapes: spiral, elliptical, and irregular. Spiral galaxies look like pinwheels. They have a central disk and two or more curved arms winding outward. The disk consists mainly of older stars, while the arms have younger stars. The arms contain much dust and gas, from which new stars can form. The Milky Way is a spiral galaxy.

An elliptical galaxy may be shaped like a round ball or may be more stretched out, like an American football. It has more stars near its center and fewer stars in its outer regions. Elliptical galaxies vary widely in size. Small elliptical galaxies are the most common kind of galaxy in the universe.

Unusually shaped galaxies are called irregular galaxies. They are not very common. Many of them have no obvious center point. Some of them appear to be the result of a crash between several galaxies.

* Milky Way
On a dark, clear night, it is usually easy to see a dusty white band of stars stretching across the sky. This is the Milky Way galaxy, a massive collection of stars, dust,

* Sun
The Sun is the star at the center of the solar system. It is a hot ball of gases that gives off great amounts of energy. Life on Earth depends on light and heat from the Sun.

* Equinox 
As Earth revolves around the Sun, the planet is tilted in relation to the Sun. Earth’s North Pole always points to the same direction in space. As a result, different parts.

* Astronomy
Astronomy is one of the oldest sciences in the world. The study of astronomy involves all of the objects outside Earth’s atmosphere. These include the Sun, Moon, planets.

* Universe
The universe is everything that exists, including objects and energy, throughout time and space. Earth, the Sun, and the rest of the solar system are only a very small part.

* Star
Stars are huge, glowing balls of gases. The closest star to Earth is the Sun. Most of the pinpricks of light that shine in the night sky are also stars. Countless more stars.
* Nebula
A nebula is a cloud of gas and dust in space. Nebulas appear in many shapes and colors. Sometimes a nebula blocks out the light of stars beyond it. When this happens, the.

* Solar system
The solar system consists of the Sun and everything that orbits, or travels around, the Sun. This includes the eight planets and their moons, dwarf planets, and countless.

* Planets
Planets are large natural objects that orbit, or travel around, stars. Eight planets orbit the star called the Sun. In order from the closest to the Sun, these planets are.

* Black hole
A black hole is an area in space with an incredibly strong force called gravity. This gravity pulls in everything that gets close. Nothing, not even light, can escape from a.

* Constellation
A constellation is a group of stars. The groups are identified according to patterns that people have seen in the stars. For example, the stars of the constellation Leo seem.