GENERAL KNOWLEDGE

Detailed explanation-1: -Our galaxy, the Milky Way, is typical: it has hundreds of billions of stars, enough gas and dust to make billions more stars, and at least ten times as much dark matter as all the stars and gas put together. And it’s all held together by gravity.

Detailed explanation-2: -Galaxies are vast cosmic islands of stars, gas, dust, and dark matter held together by gravity. Hubble’s keen eye has revealed intricate details of the shapes, structures, and histories of galaxies-whether alone, as part of small groups, or within immense clusters.

Detailed explanation-3: -Many of those points of light are actually galaxies-collections of millions to trillions of stars. Galaxies are composed of stars, dust and dark matter, all held together by gravity. Astronomers aren’t certain exactly how galaxies formed. After the Big Bang, space was made up almost entirely of hydrogen and helium.

Detailed explanation-4: -Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy’s center of mass.