Barred spiral galaxy

A barred spiral galaxy is a big group of stars shaped like a spiral, and which has a long, straight bar also made up of stars across its middle. Imagine it like a pinwheel firework with a stick going through it. Our home, the Milky Way, is one of these galaxies and has its own bar.

Barred spiral galaxy showing a distinct bar across the middle connecting the two spiral arms.

Edwin Hubble made a list of all the galaxies he could find and put them into groups according to their shapes. He noticed that some of the spirals have tight arms, some have loose arms, and others are somewhere in between. He even made a category for those with a straight bar and no spiral arms.

Bars in galaxies act like nurseries for stars. They help bring gas toward the center, where new stars are born when there is enough gas and dust around. But the bars don't last forever; over time, they might change, and the galaxy becomes a more typical spiral.

Scientists think that this whole process takes about two billion years. They've found evidence that even in the early days of the universe, some galaxies already had these bars.

Barred spiral galaxies are like big whirlpools of stars with a straight bar made of more stars in the middle. It's like a special phase in a galaxy's life, and it takes a long time for them to go from being just a spiral to having a bar.