Unknown ultrafast radio bursts reappear in real-time

Spanning hundreds of metres in a gaping circumference leaving an almost vacant imprint upon the Earth’s surface, the Arecibo Observatory in Puerto Rico would seem to yield the same appearance to a bird’s eye spectator as the moon’s craters do for the human eye when observed from Earth. Considering it is one of the largest on the planet, the Arecibo Observatory is also one of the few telescopes which is striving to pave the way for a deeper understanding of the largely-left-unknown field of extragalactic space. Though not as consuming in the amount of physical space it dominates, the Parkes Observatory in Australia (measuring a modest 64m in diameter) has also been generating lots of interest among the astrophysicist community for close to a decade now. 

This is due largely in part to astrophysicist Duncan Lorimer, who was one of the original researchers at the Parkes Observatory to have unearthed a unique and rare kind of space activity: ultrafast radio bursts which were from, as the data would suggest, a far and very distant location outside our own Milky Way.

It all began back in 2007, when Lorimer and his team were scouring through old records of the telescope’s data from 2001 and, as chance would have it, they came across one random, single, and very intense radio wave of an unknown source. This singular radio wave, though lasting only a millisecond, was seen to emit more energy than the sun would in a million years. The strangeness of this FRB (fast radio burst) only seemed to draw more attention as the team began to study where exactly this powerful, millisecond-long lasting event had initially come from. 
Through a measurement of the astronomical side effect called plasma dispersion - a process that essentially determines the amount of electrons radio waves have come in contact with along their path to the earth’s atmosphere - they determined that these fast radio bursts had travelled from well beyond the perimeters of our galaxy.  In fact, the dispersion measurements indicated that the fast radio burst observed in 2011 had originated from over a billion light years away. To put this in perspective, our own galaxy only measures a mere 120,000 light years in its diameter. These waves were seen to be coming from 5.5 billion light years away.

As exciting as this discovery may have seemed at the time for the astrophysicist community, the most recent recordings of fast radio bursts, which were once more detected at the Parkes Observatory in Australia, begin to fill another important piece to this extragalactic puzzle. The team in Australia have not only recorded one of the only seven fast radio bursts (to our knowledge) from over the past 10 years, they have actually been able to catch the event in real-time. Because of their preparedness, the team was able to alert other telescopes around the world to direct their focus on the correct part of the sky and perform subsidiary scans on the bursts to see which (if any) wavelengths could be detected. 
From these observations, scientists have learned important information that may not tell us exactly what or where the FRB’s are coming from, but does discredit what they aren’t. Some would argue that knowing what something is not is equally as important as knowing what it is, particularly when you are dealing with the potentially dark matter, as there is much less known about this topic than any other faculty within space.

When there is a great absence of knowledge, scientific theories both sound and absurd are bound to arise. Such has been the case with the mysterious radio bursts, where Lorimer has predicted that the situation will only proliferate over the next decade, stating that “For a while, there will be more theories than individual detected bursts.” 
He has even been heard to back the conjecture that these bursts could even be a sign of extraterrestrial intelligence. Duncan Lorimer, the astrophysicist who led the team at the Parkes Observatory and who the FRB’s have since been named after, was heard to toy with the notion that these waves could be the result of some friendly martian attempting to morse out a morning ‘hello’ from some far and distant galaxy. Lorimer was quoted during an interview with NPR, saying that “there’s even been discussions in the literature about signatures from extraterrestrial civilizations,” though he is yet to confirm whether he fully supports these allegations. 
In fact, the majority of the scientific community seems a little hesitant to place any weight in these, or any for that matter, speculations as they are just that; theories without any sound proof.

Before there were even any theories to dispute, however, the FRBs that Lorimer had originally collected from the data back in 2001 was widely believed by scientists (until recently) to have a cause and location that was much more local in terrain and even less original in origin. While Lorimer and his team had collected one instance of an FRB from their 2011 data, there was no other recorded instances of these radio waves being produced from either within the Parkes Observatory data set or any other like-minded devices around the world. And as scientists are known to be highly skeptical of any sole report or study produced without some kind of third party confirmation, the Lorimer bursts were written off as being a fluke of the technology that had first detected it. This suspicion seemed to only increase when in 2013, another four bursts were detected by the Parkes telescope, yet this time the FRBs exhibited traits that drew a lot of uncomfortable similarities to a radio interference known to be of terrestrial origin: perytons.

Scientists were able to conclude from the high dispersion measures of the Lorimer bursts that they were from an astronomical region. The technical science behind this measurement, which will help to understand why these waves were mistaken for perytons, is actually quite simple. The further away an object is, the more plasma it has to interact with (i.e. charged ions), which often times results in a dispersed spectrum, meaning the slower frequencies will arrive after the faster ones. The space between when these arrival times are will typically indicate an origin source that is inside or outside of our galaxy’s perimeters. This type of dispersion spectrum generally doesn’t occur with objects found within our galaxy, that is except for the unusual case of perytons. Though mocking the behaviour of a source that hails from extragalactic space, perytons are in fact of terrestrial origin and, like the Lorimer bursts, have only been observed by the Parkes Observatory. 
You can now begin to see how the scientists who originally proposed the source of the FRBs to be of a celestial origin were beginning to become undone by their own technology, a simple fault which can only be attributed to a lack of diversity within their samplings. Disbelievers and naysayers were quickly becoming more and more hesitant about granting these waves extragalactic status, so much as a unique event, until they had confirmed sightings of these waves from another telescope at a separate location. Lorimer even agreed that his findings wouldn’t be given the kind of scientific legitimacy that the community demands until confirmation from another observatory was recorded using “different groups [and], different equipment”.

In November of 2012, the desperate prayers of Lorimer and other researchers who were of the belief that these FRBs came from outside our galaxy had their answer. FRB12110, a fast radio burst of the same kind reported in Australia, was detected at the Arecibo Observatory in Puerto Rico. The distance between Puerto Rico and Australia - approximately 17,000 kilometres - is just the kind of space that researchers were hoping to put between sightings of FRBs, they could now confirm that these alien wavelengths were not an anomaly of either the Parkes telescope or its location.

Now that these FRBs have proven their legitimacy within the study of astrophysics, the next step is to find out where these bursts are actually coming from and what is causing them. Testing at the SWIFT telescope confirmed there to be 2 X-rays sources present in the direction of the FRB, but apart from that, no other wavelengths were detected. By not detecting any other kind of activity in the other wavelengths’ spectrum, scientists were able to exclude many other contending theories from being considered as valid explanations for the FRB’s origins. 
In addition to not observing these bursts in any other wavelength, they did discover that the FRBs were circularly polarized rather than linear, indicating that they must also be in the presence of some powerful magnetic field. Through the process of elimination, scientists have been able to break down possible sources of these bursts into three categories: Collapsing black holes (now known as blitzars), giant flares produced from magnetars (neutron stars with a high magnetic field), or that they are the result of collisions between neutron stars and black holes. All three theories have the potential at this point to be valid, as the information that we don’t know about these powerful bursts still outweighs the knowledge that we do have catalogued.

So what, you may ask, are the actual applications of knowing the origins of these fast radio bursts, apart from our deep-seated curiosity and fetishized hope that it may be a potential form of extraterrestrial intelligence attempting to reach out to us from galaxies far away? By eventually understanding what and where these bursts are actually coming from, scientists believe that they will soon be able to use this information to aid them in solving some of quantum theory’s greatest puzzles, ones which Einstein himself was never able to fully prove.

Forecasted start year: 
2015 to 2017


Load comments