Context: 

The first pulsar (PSR B1919+21)  was discovered by scientist Jocelyn Bell Burnell and Antony Hewish in 1967.

What are Pulsars?

• About: Pulsars are rotating neutron stars observed to have pulses of radiation at very regular intervals that typically range from milliseconds to seconds. 
• They have very strong magnetic fields which funnel jets of particles out along the two magnetic poles. These accelerated particles produce very powerful beams of light.
• Radio signals emitted from near the poles of such a star would form a narrow cone that sweeps past the earth with every rotation,  like the light from a lighthouse shining over a ship on the sea.

• Importance Pulsars: 

  • Act as cosmic tools:  The light emitted by a pulsar carries information about neutron stars, its physics and what is happening inside them.
  • Natural clocks in the universe: Many known pulsars blink with precise regularity as a result scientists can watch for changes in a there blinking and  indicate something happening in the space nearby. 
    • Through this method scientists began to identify the presence of alien planets orbiting pulsars and the first planet outside Earth’s solar system ever found was orbiting a pulsar. 
  • calculate cosmic distances: The exquisite and precise  timing of the pulses, scientists have made some of the most accurate distance measurements of cosmic objects.
  • To test theory of general relativity: The regular timing of pulsars may be disrupted by gravitational waves (he ripples in space-time predicted by Einstein) There are multiple experiments currently searching for gravitational waves via this pulsar method.

About Pulsar Glitch

• Origin: Before it was considered that neutron stars after their formation started  rotating  slowly over time, as the energy ‘saved’ by reducing the rotation rate was used to accelerate electric charges outside the star, producing the radio signals.
  • The  problem of Pulsar Glitch  was discovered  in 1969 when two research groups reported an abrupt and brief increase in the rotation rate of the pulsar PSR 0833-45.
• Study: Scientists have spotted more than 3,000 pulsars and around 700 such glitches and plotted the rotation rate of pulsars over time on a graph.
• Assumption : The familiar decreasing pattern was visible but  during a glitch, the rate increases briefly before relaxing to the original value. Scientists assume that the glitch is the result of something happening inside the star.
• Hypothesis: Although the problem of the glitch has no solution as of now, some  hypotheses surround the scientific community.
  • Presence of superfluid: The slow post-glitch relaxation hints that the neutrons inside the star were in a slippery, frictionless state, which is called a superfluid.

Also Read: 

• Formation Of Stars Part-I
• Part-II – From Formation to Cosmic Remnants

News source: The Hindu

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