by Neutrons Stars have been the most bizarre stellar body found in our observable universe ever since its discovery in 1967. These stars are the remains of a dead star and could be the definition of the word extreme because of their extreme magnetic and gravitational field. The gravity of the Neutron star is so high that it could flatten any stellar body in the universe. The fastest rotating pulsars are found to be rotating at 1/10th of the speed of light. So how are they formed? Could they destroy the universe?
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| The Electric and Magnetic field surrounding the Neutron Star. Image via NASA's Goddard Space Flight Center |
What are Neutron Stars?
Neutron stars are one of the strange things in the universe and our scientists have been clueless about its existence for so many decades. Neutron Stars are stellar objects that are the size of a city and almost 1.4 times the mass of our sun formed when a gigantic star runs out of fuel and creates supernovae collapsing into its core, crushing its electrons and protons into neutrons. When the star of mass of more than one solar mass burns out of fuel, it will stop the collapse and forms the Neutron Stars. But when the star is too massive and if it is more than 3 solar masses, the core collapses to form a Black hole. The Neutron stars are scattered in our galaxy and found abundant in our observable universe. Although not every Neutron star can be observed by our current technology, some Neutron stars don't emit enough radiation. Most Neutron stars are spotted because of the radiation emitted by the pulsars.
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| The Magnetic field around the Neutron Star |
The breakthrough of Neutron Stars
The discovery of neutron stars was an accident just like every other scientific finding. A research student at Cambridge University named Jocelyn Bell was observing the distant radio sources using a special detector. Then she found out about a strange radio pulse which doesn't seem to be random rather the pulse was regular. The pulse was first thought to be coming from an alien life form, but later a large number of these pulses are observed and that eliminated the chances of these pulses coming from an alien civilization. Applying various theories and mathematical calculations, it was found that the pulse was coming from a spinning neutron star. With the neutron star spinning, the radiations are emitted throughout the universe and the pulse is spotted on Earth when the beam aims at us. It was named pulsar because of its pulsing nature and further research made the discovery of neutron stars possible.
How Neutron Stars are formed?
Before we understand how Neutron stars form, we need to understand the properties of a star. The Stars in our universe remain peaceful for many eons because of the external pressure applied by the star's nuclear fusion reactions which balance the gravitational pull of the star's core by exerting an outside pull. The shining of a star happens due to these nuclear fusion reactions happening on the star's surface. But this equalization game is not going to last forever, as the star's fuel might run out at one point and there will be no nuclear fusion reaction to keep the external pressure going.
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| Supernova |
So when the Star's fuel burns out, there will be no nuclear fusion happening on the star's surface and hence no external pull will be generated. This might cause the gravity to take over the full control of the star and it compresses the star into its core, then a shockwave is produced in the core sending a blast of particles into the vast space. With just the core of the star intact, the gravity continues it pulls so heavily that the electrons in the atoms are forced into the nuclei and combining with the neutrons in the parent nuclei. This high dense mineral-rich substance is called neutronium.
The Neutron stars are expected to be at least 34 million years old and they might just be the oldest star in the universe. The oldest star could be the same age as that of the age of the universe. We are very lucky to not have any neutron stars in our solar system as it could lead to massive destruction. If they were here in our solar system, there will be chaos and the planets will be displaced from their orbit. Fortunately, the nearest neutron star is 500 million light-years away. Currently, many radio and space telescopes are on the lookout for more neutron stars in our galaxy.
Pulsars and Magnetars
Pulsars are rotating neutron stars that are discovered to emit a pulse of radiation that usually lasts for a few milliseconds. After the core of the star got collapsed and the neutron star is born, they rotate extremely fast due to the consequence of the conversation of angular momentum. They can rotate from 60 times per second and up to 600 times per second. The pulsar emits its radiation in two opposite directions and this is the flicker of light rays perceived from our observations. The Pulsars even have more strong electric fields which are up to 1 quadrillion times stronger than the Earth. They can radiate the light in multiple wavelengths, even though they appear to be flickering, they are actually a strong continuous beam of light. These are mostly found on Radio telescopes.
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| The Pulsars. Image via NRAO |
Magnetars are neutron stars known for their extremely powerful magnetic fields and the magnetic field is 1000 times more powerful than the pulsars and a few trillion times stronger than our Earth. They release enormous amounts of radiation in the form of flares, x-rays and gamma rays. Recently the closest magnetar has been spotted inside our Milkyway galaxy by the detection of Fast Radio Bursts (FRB) in April 2020. The properties of the Magnetars are bizarre, but active research has been going to unlock the mystery of the Magnetars.
