Still, different pulsars have different spin rates. One pulsar spun only 0.2 time per second as opposed to 1000 times per second. Others had all sorts of numbers, ranging from 10 to 900, but most are somewhere around 1 or 2. Usually, young ones tend to spin faster than old ones. This is because pulsars slow down at a detectable rate. One slows down less than 36.5 billionths of a second per day! But because its spin is so extremely regular, such a minimal deficiency can be found. For example, the pulsar at the heart of the crab nebula now only rotates 360 times per second. There are many possibilities for why different pulsars have different rotation speeds: they formed under different circumstances, some may be younger than others or the rate of the spin was affected by neighboring bodies.

As do all objects in the universe, pulsars release energy. Picture a top. First, you spin it, thus you are giving it energy, but after a moment or two, all the energy put into it runs out, so it slows down and finally stops. A pulsar is primarily the same thing: it starts with a sizeable amoung of energy, but over time, all that wears away because of the extremely rapid spin. But sometimes, the energy with which a pulsar starts with is small. This might be because the compression was not so great, or the supernova itself was not very massive.

Much to scientists’ surprise, a pulsar was found which defied all the rules of cosmic mechanics. This one was relatively old, older than the Crab Nebula Pulsar; nevertheless, its rotational rate was more than 960 times per second! In this crucial moment, scientists considered the third possibility by which a pulsar’s spin is affected. They theorized that another star was trying to pull the pulsar here and there. But, the pulsar itself was just as massive as the other star and thus, a kind of tug-of-war action appeared, with the two bodies tugging on each other, activating each other and thus getting energized. With more energy, an object spins faster. And sure enough, a small star was later found near the pulsar!

As I mentioned, an extremely small size, super-density and a strong magnetic field allows the pulsar to be what it is. And also, as I mentioned, a pulsar has as much mass as our sun. Normally, one would ask, “How can an object be so small and yet be so massive?”

Stars form from nebulas or clouds of gaseous material. Usually, a shock wave from a nearby exploding star causes a part of the nebula to contract, first slowly, but eventually speeding up. Over time, this becomes a disk, a spinning disk and a red ball of hot gas forms in the center. The ball sweeps up all the particles surrounding it, growing in size at the same time. Some million years later, the young star expels all the excess gas of its formation far away, into the distant outer regions. A reaction has begun where the nuclei of hydrogen atoms combine with heavy hydrogen deuterons to form the nucleus of the inert gas helium. The contraction is halted and, it has begun its stable existence as a fully mature star.

All stars start with nearly the same amount of hydrogen fuel, but the rate at which it is transformed into helium is different in all stars, depending on the mass of the object. Very large stars with diameters 400 times that of our sun can blow up as a supernova in less than a few million years, while our sun can last for another 5 billion years! The sun will end up as a white dwarf, an old star that has exhausted its available fuel and collapsed, but continues to radiate light. But the road to a pulsar is very different: once a supergiant’s fuel runs out, it would explode as a supernova. The outer layer of gas and hot material is expelled and only the core remains. The core then, starts to contract, until it is less than 10 miles or so in diameter, thus making it extremely dense.

       

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