Globular Clusters 

Science Fridays

      As I've said in the past, the universe is an amazing place.  There are things out there that are truly remarkable.  There are novas, and quasars, black holes and neutron stars, and nebulae everywhere you can turn a telescope.  Also, no matter where you look there are other galaxies - like the sand on the seashore they are so numerous.
      Surrounding most of the galaxies are dwarf galaxies that orbit the bigger galaxy.  Did you know that surrounding our own Milky Way Galaxy are fourteen dwarf galaxies in orbit around us?  The largest one is the Large Magellanic Cloud.  And found all over the place in every galaxy; regular or dwarf are globular clusters.

      Globular clusters are areas packed with stars in unimaginable numbers, gravitationally attracted to each other into a small space.  Above is one of the largest ever observed, Omega Centauri.  Omega Centauri is a cluster stuffed with over ten million stars, packed into an area of 150 light years.  That would make the star density of that area be about 66,000 plus stars per light year.
      Lets put that into a little perspective.  Our nearest neighboring stars are Alpha Centauri, and Barnard's Star, each sitting about 4 light years away.  That seems to be the normal distance for stars to be separated from each other.
      Each planet within our solar system has an orbit about twice the distance of the orbit of the previous planet's orbit (or more specifically each planet's orbit is about two thirds the distance of the orbit of the next planet's orbit).  The asteroid belt is located in an area that should house a planet according to this mathematical configuration.  Neptune is the farthest planet with an orbit about twice the distance of Uranus' orbit.  At twice the distance of Neptune's orbit is the Kuiper Belt. Planetary orbits are not evenly spaced from each other but get progressively larger as they go out from the sun. 

 

      Beyond the Kuiper Belt is the Oort Cloud.  This area is filled with comets, asteroids, and planetoids, and covers a huge area.  The Oort cloud basically doubles the size of our solar system.  The Oort Cloud contains the farthest objects orbiting our sun.  From the Sun to the outer edges of the Oort Cloud is a distance of about 50,000 AU (Astronomical Units).  A light year is 63,000 AU.  If you consider that other stars have Oort Clouds of their own the distance between star systems is closer.  If we were much closer to Alpha Centauri, for instance, objects in the Oort Cloud would have a figure eight orbit, as they would orbit around both systems.

      This makes the diameter of the Solar System about 200,000 AU - almost two light years across.  At this size compared to the density of the Omega Centauri globular cluster, the Solar System would contain 120,000 stars.  That means there would be a star sitting roughly at about the orbit of the earth – four of them, and there would be about eight stars just beyond the orbit of mars, 16 out into the asteroid belt and so forth.  In the picture below there would be roughly one star at every cross point in the grid pattern.  

      To say that nothing could live in a globular cluster would be an understatement.  Besides being burnt to cinders, you would be pulled apart by competing gravitational forces.