Welcome to the Astro Minute, where we’re exploring the universe sixty seconds at a time. I’m Lauren Smyth, and today we’re looking at galaxies.



Across the universe, stars, planets, and clouds of gas and dust clump together in structures we call galaxies. There are upwards of two trillion galaxies in the observable universe, ranging in size from hundreds to millions of light years across. They are spiral, elliptical, and irregularly shaped, and often have supermassive black holes at their centers. Each galaxy contains thousands to trillions of stars, making the current star count in the universe some two hundred billion trillion.



The Andromeda Galaxy, a giant spiral in our own Local Group of galaxies, is the only galaxy that can be seen from the northern hemisphere naked eye. Look about halfway between the narrower side of Cassiopeia’s W and the nearest corner of the Pegasus Square to see this fuzzy patch of a trillion stars.



I’m Lauren Smyth, and that’s your AstroMinute.