As one of the strangest entities of the cosmos, Pulsars, otherwise known as the “lighthouses in space”, are spinning neutron stars that emit electromagnetic radiation. This radiation can only be seen with the human eye if that person is standing in the same path as it. The reason that they are referred to as “pulsars” is because of the radiation emissions that seem to be pulsating among the stars.
Though they may look like your typical star, blinking on and off, they are actually far from it. To be exact, pulsars are artifacts of what once were enormous stars. They are formed when a massive star, sometimes eight times the size of our sun, explodes as a supernova. The outer layers are then hurled into space and the core is squeezed by gravity.
While most will explode into black holes thanks to the sheer size, a good majority of the smaller ones don’t have that same force. Instead, they end up increasing in rotational speed, spinning hundreds of times second, emitting beams of radiation that we can see.
When Were Pulsars Discovered?
The first radio pulsars were discovered in 1967 by an Astrophysicist from Northern Ireland by the name of Jocelyn Bell Burnell, while she was still a student at Cambridge University. She discovered the pulsars in collaboration with her advisor, Dr. Anthony Hewish.
It was in July of that year that she detected that something was off on her chart-recorder papers that were used to track stars in the sky. At first, her and Hewish had no idea what the signals were doing. She found that she was getting a pulsating signal that was pulsing with odd regularity. It was named “Little Green Man 1” at the time to reference sci-fi extraterrestrial culture of the time. Eventually, that pulsating signal was dubbed a “rotating neutron star”.
It was long debated that she did not receive a Nobel prize for her discovery, as it was one of the largest discoveries in space history, though, in 2018, she was finally given the biggest recognition for her great space achievement when she was awarded the Special Breakthrough Prize In Fundamental Physics.
PSR J0348+0432 – The Big Kahuna
Just within this past decade, astronomers stumbled upon one of the largest objects in space that we have found to date. They discovered PSR J0348+4032 using ESO’s Very Large Telescope. This specific pulsar is two times as heavy as the sun, though it is only 20 km in diameter. Neutron stars are known to be incredibly dense, though the amount of matter that is packed into this relatively small space was very surprising.
This star spins at 25 times per second, emitting a large beam of electromagnetic radiation. What is even stranger is that it has a companion star known as a “white dwarf”. The combined gravity of the stars creates visible ripples in space, which is why the star was so easily discoverable.
Pulsars have the most energy when they first form. They begin with high rotational speeds, releasing electromagnetic power over millions of years. They will continue to slow down after about 10 million years (though they can last for almost 100 million) before eventually going silent.
Because pulsars spin with mysterious regularity, astronomers use them as natural atomic clocks. They are so accurate in terms of time keeping that astronomers actual compare them to standard, mechanical timers.
Astronomers believe that the collection of pulsars create the most accurate map of the galaxy. If you look at the NASA Voyager craft, you’ll find a map with 14 different pulsars in our region around the sun. Essentially, if there were extraterrestrials out there who wanted to find Earth, pulsars create the most accurate map out there.
If you know anything about the band Joy Division, you probably know about their most popular album cover from Unknown Pleasures, which was released in 1979. The picture on the album cover originates from the work of Harold Craft, a postgraduate student who did a thesis on Jocelyn Bell Burnell in 1970. Those mysterious wiggly lines are actually a graphical recording of a pulsar known as B1919+21.
The closest pulsar to Earth is the PSR J0108-1431. It is right in the path of the Cetus constellation, which is about 280 light years from Earth. This pulsar was discovered in 1993 by Thomas Tauris, a Danish astronomer, using the Parkes 64-meter radio telescope. It took so long because the luminosity is unusually low.
This particular pulsar is weak in relativity, 1000 times weaker than your typical radio pulsar. Astronomers believe that PSR J0108-1431 is just the tip of a huge group of dim pulsars that are spread around the Milky Way Galaxy.
Latest Pulsar News
China’s five-hundred-meter telescope has now discovered 86 pulsars since it began operating in 2016. This telescope, known as FAST, has achieved in-motion scanning abilities that have helped it to exceed prior expectations. According to Li Di, the chief scientist of the FAST Project, the telescope has actually just detected one of the faintest and fastest pulsars that has ever been seen.
Scientists have just recently discovered a pulsar (PSR B1957+20) with a brown dwarf companion. This particular pulsar is known as a “Black Widow”, as it emits powerful radiation blasts that consumer companion stars. As the Black Widow continues to consume the brown dwarf star, scientists have noticed that it has started to create an SOS signal, and a very musical one at that. Listen closely and you can hear the Brown Dwarf as it sings a steady Eb note with small percussive elements in-between.