top of page
Search
Writer's pictureEngineering Pivot
Nov 24, 20243 min read

An Overview on Pulsars

By Saatvik Sanjay

Rendering of a Pulsar
Artist's Rendering of a Pulsar

Image via Unsplash.com


Introduction


In 1967, Jocelyn Bell from the University of Cambridge discovered the first evidence of pulsars, coming from only one part in 10 million “squiggle”  on a line. She went on to find four more pulsars and her work (but not her) went on to win the Nobel Prize in physics. Today, we know of several thousand pulsars and continue to discover more. Their uses are varied: from testing Einstein’s theories to figuring out the age of the universe to helping identify dark matter. 


What is a Pulsar?


Our current knowledge of physics tells us that pulsars are neutron stars that spin rapidly, emitting pulses of light at regular intervals so precise that they rival atomic clocks in terms of consistency. When the core of a massive star collapses at the end of its life cycle, it leads to electrons and protons in the dense matter combining to form neutrons. If the mass of the core is between 1 to 3 solar masses, then this process stops leading to the most dense object in the universe—the neutron star. One sugar cube of this star could weigh upwards of one trillion kilograms, the mass of an entire mountain. Neutron stars on their own are usually not detectable. More often than not, neutron stars are found spinning as either pulsars or magnetars releasing huge amounts of energy. Pulsars in particular have very strong magnetic fields that shoot out jets of particles at the magnetic poles. These accelerated particles produce very powerful beams of light that sweep across the sky—almost like the light from a lighthouse. 


Notable Pulsars


Some of the most famous pulsars of our time include the Vela Pulsar, the Crab Pulsar, and the Hand of God Pulsar. The Vela Pulsar is located about 1000 light years away from Earth and spans only about 12 miles in diameter. But it makes over 11 complete rotations every second, spewing out charged particles at 70% the speed of light, with the jets being over 0.7 light-years long. Data obtained from the Chandra observatory suggest that the pulsar may be slowly wobbling as it spins. The shape and motion of the pulsar’s jet look similar to a rotating helix, which is a shape achieved through a wobbling motion. If it is confirmed then this makes Vela one of the first pulsars to be a wobbling neutron star. A bit farther away at 6500 light years away, we have the pulsar at the heart of Messier 1 or the Crab Nebula. The remnant of a violent supernova that was visible during the daytime thousands of years ago, the neutron star pulses about 30 times per second and is responsible for the blue glow at the interior of the nebula. Bright wisps of light are seen moving outwards at half the speed of light into an expanding ring around the pulsar, which is seen through both X-ray and optical images. The Hand of God pulsar is responsible for creating a “wind” of particles that resemble the shape of a hand under an X-ray. Spinning around nearly 7 times a second, it ejects material that interacts with magnetic fields around it causing it to glow with X-rays. Astronomers believe that this pulsar’s wind is heating the nebula around it, causing it to glow with a lower-energy X-ray light. 


Conclusion


In conclusion, pulsars, as fascinating as they may seem, are still largely undiscovered in their purposes. Recently, they have been used for the detection of dark matter due to the gravitational lensing of this matter between the pulsars and our telescopes. This is one of the many ways that goes to show how pulsars, while yet another mysterious entity, still play a vital role in our understanding of the universe. 


Sources: 



bottom of page