Picture of the day - April 18, 2008

M51 - The Whirlpool Galaxy

Photo courtesy of NASA. Messier object 51 (M51) is commonly known as the "Whirlpool Galaxy" because it resembles, well, a giant whirlpool. What creates this "look" is the way all of the galaxy's stars, planets, moons, solar systems, rocks, dust and gases are rotating counter-clockwise around its super-massive central core. All spiral galaxies including our own Milky Way are "glued together" in the same way: by the gravitational force of the central core preventing the objects revolving around it from simply flying off into space. Gravity is the wonderful unseen force that keep us all planted firmly on planet earth, makes the tides ebb and flow, and keeps the moon fixed in its rightful place in our night sky. But it is also the force that keep the universe's galaxies from flying apart and wreaking all kinds of celestial havoc. If God were to suddenly decide to turn off the "gravity switch", the uniformity of the universe as we know it would instantly turn into chaos. All life would immediately come to an end, and we would literally "never know what hit us". But we don't have to worry about that - our friend gravity is here to stay, keeping us all in our appointed place as we speed through the universe on the surface of our amazing planet.   Click here to comment on this picture.   Visit the POTD Archives for previous "Pictures Of The Day"!     Submit a photo of your own!                                 Place the "Picture of the Day" on your website, for free! Why I publish the "Picture of the Day"