Galaxy f62: Galaxies are titanic swarms of tens of

Galaxies are titanic swarms of tens of millions to trillions of stars , orbiting around their common center of gravity. They also contain interstellar gas and dust. Galaxies show a range of shapes that astronomers group into three basic classes: spiral, elliptical, and irregular. Galaxy , any of the systems of stars and interstellar matter that make up the universe. Many such assemblages are so enormous that they contain hundreds of billions of stars. Galaxies consist of stars, planets, and vast clouds of gas and dust , all bound together by gravity. The largest contain trillions of stars and can be more than a million light-years across. The smallest can contain a few thousand stars and span just a few hundred light-years. A galaxy can contain hundreds of billions of stars and be many thousands of light-years across. Our own galaxy , the Milky Way, is around 100,000 light-years in diameter.