Galaxy

space · stars · huge

Star cities. A galaxy is a huge system of stars, gas, dust, and mysterious dark matter all bound together by gravity. The average galaxy holds about 100 million stars!

Milky name. The word 'galaxy' comes from the Greek word for 'milky,' named after our own Milky Way galaxy where Earth lives.

Tiny to giant. Galaxies come in wildly different sizes, from dwarfs with fewer than a thousand stars to supergiants packing one hundred trillion stars.

Hidden heart. Many galaxies have a supermassive black hole right at their center, anchoring everything that spins around it.

Mostly invisible. Most of a galaxy's mass is actually dark matter, we can't see it, but only a few percent shows up as glowing stars and nebulae.