May 1st, 2024, at 12 o’clock at night, if you look east, you will see Scutum constellation without a telescope just above the ground. Like Pulsars Star
You know, what’s the weirdest thing about constellation? Well, last year, in the month of September, when an Australian research team was detecting some radio signals in the night sky, you know, so that some common objects emitting radio waves, whose neutron stars, pulsars, or their magnetically stronger siblings, could be detected, then surprisingly, they saw a mysterious radio signal coming from the direction of the Scutum constellation, which was not matching any known object.
And you know, what’s worse, this signal kept flashing continuously for about 5 minutes, and then suddenly disappeared and came back exactly after 22 minutes. Now, after this mysterious incident, when a little more investigation was carried out on thus signal, then it was found that this signal has been getting to us continuously for the last 35 years, and yet, we have not been able to find its exact source.
Every time, just one message would pop up on the computer screen, match not found. So now the question arises, is there any alien civilization trying to tell us its location through this strange radio signal? Because, it is mostly possible to repeat the same signal every 22 minutes for the last 35 years, if its source is an unnatural object. An ordinary pulsar or magnetar, for example, slowly loses its energy and stops sending radio signals after a point.
So, there is one responsibility that maybe it has unnatural source.
Or, the other possibility is that there are some objects in this universe that scientists have not been able to understand completely yet, and these radio waves are emitting from them.
How was discovered!
So, what exactly can these radio signals be? We will have to do a little research on our level. For this, we will have to start the story from the very beginning, that how was this discovered first?
Now, first of all, this weird radio signal was discovered by an undergraduate student for his ordinary college project. Not for a serious purpose. Actually, the story of this signal starts from another signal, which was discovered by Tyrone O’Doherty, an undergraduate student at Curtin University in Australia in 2020.
O’Doherty was working on a project, under which he was identifying unknown blinking radio signals from the old data of the southern sky.
Now, during this project, he found a radio signal from a 2018 data, which was throwing the beam of radio signals towards the earth like a beam coming from a lighthouse.
So, when he told his mentor, radio astronomer Natasha Hurley Walker about this beam, he himself started researching this signal.
First of all, he saw the location of that signal in different frequency data, but unfortunately he did not find any clues about the signal there. But then, he saw a pattern hidden in the radio data. She saw that this signal is being repeated every 18 minutes. She immediately knew that this could be game, changing discovery of her career. But passion before she could study that object in detail that signal disappeared with in just three months. And seeing this unexpected disappearance, she and her team got even more confused.
What could this object be?
So to find the answer to this, they scanned the entire southern hemisphere again to find one clue. And even after researching for many months, they didn’t find a clue. And so, they were about to stop their study when they found a signal that was coming back after 22 minutes.
Now, after the mysterious disappearance of that 18-minute signal, Natasha and her team started scanning the entire southern sky with the Murchison-Winfield Array Radio Telescope in Australia. And then, they found another signal similar to the one found in the Scutum constellation near Sagittarius, which kept coming back every 22 minutes. They named it J183910. But, now the question arises, was it related to that 18 minutes signal? Natasha again studied the past radio data of that entire region. Actually, this signal was already detected by the Indian and American radio telescope in 1988. After its detection, that data was lost in a pile of data.
And then, during this current study, when this data was revisited again, they found out that this signal has been continuously repeating every 22 minutes for the past 35 years. What it comes it gives a long radio burst for 5 minutes.
Good News for astronauts because with the help of these signals, the astronomers could now know how far that unknown source object is from us.
When these calculations were completed, it was found out that this source is 15,000 ly away from the Earth. That’s mean now only one thing was left to know that what exactly is the subject 15,000 ly away from us!
So in this search, first of all, Walker and his team starting matching all the know objects that emit radio signals to this mysterious signal. Surprisingly, they found similarities in the old data and this signal.
There were many radio signals in that data were blinking exactly like J183910. So when they researched the source of these similar signals, they found out that all the old signals were emitting from the typical category of neutron stars, pulsars.
When big stars explored 10 to 25 times from the Sun they turn into super dense neutrons stars smaller than that instead of becoming white dwarfs.
Now, the mass of some neutron stars here is so high that due to gravity. their matter starts collapsing within itself. This compresses the stars and their sized becomes smaller. And so to conserve their angular momentum, these stars start rotating very fast. This is similar to when a ballet dancer pulls in her hand then the speed of her movements increase. And such rapidly rotating neutrons stars are called pulsars by astronomers.
These are more dense than neutrons stars. Because of this dense environment the neutrons present in pulsars decay in electrons and positrons and start rotating rapidly on its surface.
Now, you tell me a simple question, what is created from a moving electric field? Yes, a magnetic field. And particle present in pulsars like electrons, due to being charged as soon as they come in contact with this magnetic field they accelerate in its direction. During this time, they throw their energy out of the store in the form of radio waves. The axis and its rotation axis of a pulsar or not, always the same. Then the tips of their magnetic axis emitting radiation periodically points towards our earth.
In other words, we can say that these pulsars blink in one way, Which is exactly like our strange signal. So what mystery solved?
Studied About Pulsars Star
When astronomers studied the pulsars, then they slowly realized that they were on the wrong track from the beginning. Because usually to study the behavior of pulsars, scientist, calculate the ad signals or their pulsating period, so that can predict how long the pulsars will be alive. And so, the recently found radio signal, is it really because of Pulsars.
To l know this scientists plotted all the pulsars on the basis of their rotation period in this graph.
Now the pulsation period of normal pulsars is between 0.25 to 2 seconds. That’s why all the pulsars come here in this region. But because of continuous rotation, eventually pulsars start losing their energy.
If the energy is reduced then obviously its rotation speed will also decrease. If rotation speed is reduced, then its pulsation period will increase. Pulsars will move in this region, which astronomers call the Death Valley.
The countdown of Pulsars’ life starts as they reach the Death Valley.
The rotation rate of the pulsars in this region, slows down to such an extent that they are able to emit radio wave amount of difficulty.
When the pulsars cross this deadline, their rotation slow down to such an extent that they are unable to emit radio waves.
When astronomers plotted the signal they got in this graph, they were just baffled.
Because as you can see the signal was emitting radio waves even beyond the deadline. One thing was for sure this object is definitely not a pulsar. But then they were struck that there is a special category in pulsars. Magnetars.
Magnetars: Stars who is magnetic field is 1000 times more than that of normal pulsars. In addition they also show a slightly longer pulsation in comparison to pulsars.
That’s why scientists thought that maybe this kind of stars will be able to explain this signal. But when they plotted this star in this graph, they saw that it was not even near that signal.
Due to being highly energetic, X-rays also emit along with radio waves. The signal they got was only emitting radio waves. That’s why astronomers had to rule out the possibility of it being a magnetar.
That is all in all the signal scientist got was neither a pulsar nor a magnetar. And it was clear that the radio signal they recently got was not matching any known object for astronomers.
That’s why according to them, this signal is still a long standing mystery.