Neutron Stars

Neutron stars are leftovers from huge beautiful explosions called Supernova.  They are the destiny of the dying stars if their core mass ends up less than three Sun masses.  They are very dense.  What is their density?  10^12  g/cm^3.  Think about that for a minute. More fascinating is that they rotate very rapidly.  Can you imagine how fast they rotate?

Let's get some perspective.  The Earth goes around itself once every 24 hours.  Our Sun,  the size of a million Earths,  rotates around itself once in about 25 days.  These dense stars, Neutron stars,  on average have a mass equivalent to 1.5 Sun masses.  How fast do you think they rotate?  Like Sun? Maybe twice faster? or maybe 25 times faster, going around themselves in 1 day or so?  Are you ready?

Neutron stars have a period of 0.0003 to 4 seconds.  That is every 4 seconds they can rotate somewhere between  once to 12000 times, while being as big or larger than our Sun!  Can you imagine something that huge spin that fast?  60 times to 720,000 times a minute?  Can you imagine if our Earth rotated that fast?  If you cannot be amazed and fascinated by this, like our professor said today, I give up!  I leave and never write or teach anything else.  That is it!

Yet, these massive and rapidly rotating bodies have properties with frequencies more accurate than the best atomic clocks we humans have built to date.  They are universe's most accurate clocks.  I get to that property some other time.