Unravelling the mysteries of deep space, one fast radio burst at a time
In the earlier years of the space age, then US ambassador to the UN, Adlai Stevenson, proclaimed: “We can never again be a squabbling band of nations before the awful majesty of outer space”.
Although his optimistic vision hasn’t fully materialized as of yet, humankind is unraveling the secrets of the cosmos on a daily basis, exponentially learning more with each new technological innovation, each new understanding and each new discovery.
And while the old adage “the more we learn, the less we know” may ring especially true through the enigmatic spans of space, astronomers and astrophysicists alike remain more motivated and committed than ever to turn each next corner in search of new information that can shine more light onto our place in the Universe.
For it’s an interesting equation at play: the more we learn about the (inter)galactic world(s) around us, the more we consequently learn about ourselves. And, like it or not, this knowledge is as infinite as it is elusive, as is our own self-defined limitation to truly understand it.
To take a recently-discovered phenomenon as a prime example of this, we can look to Fast Radio Bursts [FRBs for short], which are millisecond-long blips of cosmic noise — inexplicably intense signals that glide through the dark waters of space and cover inconceivably long distances.
No more than a decade ago, astronomers and astrophysicists didn’t even believe that they existed. Now, equipped with new technologies and methods of detection, sky-watchers are left scratching their heads at FRBs, not sure what to make of this mysterious intergalactic phenomenon.
“It’s not so often in astrophysics that there’s a new phenomena that we really don’t understand and we have the opportunity to learn something genuinely new.”
- Jason Hessels
These signals are so powerful that they, ostensibly, don’t make any sense. Emanating from billions of light years away, they’re still capable of overpowering the pulsars bouncing around our own galactic playground, leading many to deduce that they must originate from the likes of some incomprehensibly massive astrophysical anomaly — black holes colliding or imploding, white holes, stars exploding — and, of course, aliens.
Because the thing about FRBs is that the intrigue goes well beyond their ability to travel enormous spans of distance. Some of them don’t seem natural at all. In fact, some seem so tantalizingly artificial that it has resulted in researches looking to explain how an alien civilization can possibly harness such power in the most hypothetical of contexts.
One particular signal, known as the Spitler Burst — discovered in 2012 by Laura Spitler, features a repeating signal — consistent as any intended transmission from an alien civilization. But, of course, pragmatism is quick to overpower imagination among those at the front lines of these discoveries, leading to a very constrained and cautious approach to interpreting such tantalizing data.
Nevertheless, the excitement is boiling over more rapidly by the day. Ten years ago, we didn’t even believe FRBs to be real — today, we’re salivating at the chance to interpret each forthcoming signal. This alone says a lot about our progression and, more importantly, about our need to find answers.
And so, wanting to gain insights from someone situated at these front lines of discovery, someone who could really paint a picture of what it means to interpret these cosmic anomalies, I didn’t have to look farther than Avi Loeb, an expert in the field of intergalactic transmissions — artificial or not.
“In my view, it is most likely that FRBs are the bright analogs of pulsars, which are spinning neutron stars with strong magnetic fields.”
Avi went on to detail that the duration and radio-frequency of FRBs seems similar to the flashes that emanate from pulsars (highly magnetized neutron stars that emit beams of electromagnetic radiation out of its magnetic poles), but that they’re intrinsically billions of times brighter and more sporadic. Whereas pulsars are detectable to us only within the limits of our Milky Way Galaxy, some FRBs are so bright that they seem to originate from as far as the edge of our known Universe.
“One possibility is that FRBs are associated with very young neutron stars (only decades old) with extremely strong magnetic fields, called magnetars.”
Avi, like most astronomers, pointed to magnetars as the most likely explanation of FRBs; however, we can’t be certain, and this is exactly where things get interesting. Especially for Avi himself.
“At the moment we do not have a smoking gun that clearly indicates the nature of FRBs, so all possibilities should be considered, including an artificial origin. It is possible that FRBs are a mixed population with a variety of source types.”
This is the juncture where all researchers begin to diverge and segregate themselves into camps — believers and non. Avi himself remains open to the possibility of an alien civilization, simply because it’s not one that ought to be taken off of the table until it can be clearly refuted. We simply don’t know — and this is the crux of our motivation to scour the skies with exponentially increasing enthusiasm.
Avi has written several papers exploring FRBs and theorizing on their origins, taking the most specific nuances into consideration to contribute to the ongoing academic discussion on this topic.
One idea that Avi presented, under the more imaginative umbrella of an alien civilization causing these transmissions, is that the signals are being emitted from a tremendously powerful beam of light that is used to propel cargo — he has written two papers specifically detailing how this would work:
“In order to produce FRBs across cosmological distances, one needs to use a huge amount of power, comparable to the total power in sunlight intercepted by the Earth. This would require a vast engineering project, millions of times more ambitious than we ever contemplated here on Earth…
…If the communication was aimed for short distances then the beacon of light would not have been so powerful, to save energy. Instead, a civilization might generate a powerful beam of light to propel cargo with a sail and we could observe the leakage of that radiation outside the boundaries of the sail.”
To make it clear, Avi isn’t saying that FRBs stem from an alien civilization — it’s just one drop in a bucket full of many possibilities, most of which are less sensational and, albeit, more likely. But the key thing to appreciate here, regardless of what kind of interpretation we’re looking at, is the fact that we’re even looking. Avidly.
Granted, we don’t know what it is we’re looking at — whether we’re tuning into large beams of artificially-emanating light or whether we’re witnessing magnetars work their magic. What we don’t know is what motivates us to know, but whatever the outcome may be, it’s our curiosity that ought to be applauded.
For it’s this intrinsic and unrelenting curiosity that reveals a handful of things about ourselves — namely, that we’re desperately trying to make sense of our own place in a Universe that we know very little about.
The most inspiring thing about all of this, something that we may refer to as the big takeaway here, is that we learn about ourselves regardless of whatever we find at the other end of that signal, and we do it in a way that seeks to unify us, either through the knowledge we gain, through the collaborative effort we put in, or maybe, just maybe, through the fear derived from deciphering that these signals are threats emanating from an alien civilization.
Curious to browse more of Avi’s work? Links to some of his papers below.
Image courtesy Michael Misof