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The universe is about 13.8 billion years old and is home to different kinds of galaxies, from spiral to elliptical and those with or without bulges.
Astronomers previously believed spiral galaxies formed about 6 billion years ago, but a new study by a group of astronomers from the University of Missouri in the U.S. has called this belief into question
The study has revealed more spiral galaxies in the universe’s youth than astronomers had expected.
Spiral galaxy
Spiral galaxies are twisted collections of stars and gas that often have beautiful shapes and are made up of hot, young stars.
Most of the galaxies (approximately 60% of all galaxies) that scientists have discovered so far are spiral galaxies, as opposed to the other two main categories of galaxy shapes—elliptical and irregular.
The Milky Way, the galaxy that includes Earth and our solar system, is an example of a spiral galaxy.
Most spiral galaxies contain a central bulge surrounded by a flat, rotating disk of stars.
The bulge in the center is made up of older, dimmer stars and is thought to contain a supermassive black hole.
Approximately two-thirds of spiral galaxies also contain a bar structure through their center, as does the Milky Way (barred spiral galaxy)
The disk of stars orbiting the bulge separates into arms that circle the galaxy.
Spiral galaxies are thought to evolve into elliptical galaxies as the spirals get older.
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