The long arms of the galaxy are in constant flux, turning and changing. The entire Milky Way is effected by density-wave patterns like waves in the ocean. The galaxy is also growing, its mass increasing at an astonishing rate. And to complete this cosmic dance, graced by a breathtaking light show, the whole dance floor is turning. Thankfully for us, it is not a dance of chaos, where billions of heavenly bodies are smashing into each other.
Gravity governs the dance, allowing stars, planets and moons to relate coherently to one another.
A fitting display for the ballroom of Heaven. Expand the dance floor, the entire universe is rotating, pulsing with movement. The known universe is a home to over 100 billion of these graceful galaxies, some larger, some smaller than our own. If you were to make a fist and point it anywhere toward the sky, it would cover an area of space containing one million galaxies. It is estimated at ten trillion, trillion, trillion trillion tons, fully dressed.