Interior structure of the Crab Nebula, thought to harbor a rapidly spinning pulsar.
Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University).
 
 

On June 11, 2008, NASA launched the Fermi Gamma Ray Space Telescope (formerly GLAST) on a mission to map extremely high frequency electromagnetic energy across the sky. Although gamma rays are said to travel up to billions of light-years through space, they are unable to penetrate Earth's upper atmosphere, so Fermi is in an orbit outside the regions of greatest density.

According to a recent press release, scientists from the University of California Santa Cruz Institute for Particle Physics have been able to identify 16 new pulsars using the signature of their gamma ray emissions alone. In the past, pulsars were usually discovered by monitoring radio waves, whereas Fermi has found what have been deemed "radio quiet" pulsars.

Prevailing theories of stellar evolution describe pulsars as neutron stars that are rotating at high speeds. A neutron star is theorized to form when a star eventually collapses at the end of its life cycle, no longer able to resist the gravitational forces that draw it down into its own center. As the star contracts, it spins faster and faster, similar to what happens when an ice skater's arms are drawn in close: angular momentum increases, resulting in faster rotation.

The magnetic field surrounding a neutron star is said to become focused at each pole until an intense, narrow beam of radio waves shines out from the poles like twin beams of a lighthouse. If the beams are not pointed directly at Earth, they are not detected. Consensus opinions assume that there is a large population of neutron stars in the galaxy, so an assumed population of radio-quiet pulsars must also exist.

A neutron star is so compressed that all the electrons have been crushed into the nuclei, combining with the protons to form neutrons. The neutrons are then packed so tightly that the empty space between particles is also eliminated. The intense magnetic and electric fields surrounding pulsars are supposed to accelerate charged particles to near light speed, and it is those particles that generate gamma ray emissions.

The Crab Nebula pulses 30 times per second. That means the star rotates 30 times per second, but there are pulsars with frequencies of 716 hertz. The forces generated when billions of megatons spin as fast as a power drill means that the stars should tear themselves apart, except enough mass is added to the theory for gravity to hold it together.

Another possibility, one not considered by contemporary astrophysicists, is that electrical oscillations are causing the rapid flicker of pulsars. The regular frequency is not mechanically generated. Instead, it is the capacitive, resistive and inductive electrical environment around the star. Compacted matter and extreme rotation are not necessary. Electricity traveling through circuits provides a coherent explanation that is consistent with commonly accepted electromagnetic theories, as well as with laboratory experiments.

Stephen Smith