In the last week of August, an Indian postdoctoral researcher at the University of California, Berkeley, picked up 15 powerful pulses—Fast Radio Bursts (FRBs)—from a dwarf galaxy three billion light years away from earth. Dr Vishal Gajjar is with the Breakthrough Listen project, a $100m research programme aimed at discovering civilisations beyond earth. The project was founded by cosmologist Stephen Hawking and Russian billionaire Yuri Milner. Gajjar’s research team accumulated 400 terabytes of data on the source of the pulses in five hours.
Speculation ran rife. Were the radio pulses emitted by neutron stars or black holes? Or, were they the handiwork of extraterrestrial intelligence? Gajjar told THE WEEK that the radio pulses were detected at the highest frequency and widest bandwidth ever attempted. “It is a testament to the capability of the backend that we designed. If extraterrestrials are trying to communicate with us, they will probably send signals of this nature.”
Excerpts from an interview with Gajjar:
What is the objective of the Breakthrough Listen project?
The goal of the project is to search for extraterrestrial intelligence. We have designed this unique backend instrument and attached it to the world’s biggest telescopes. One is in Green Bank, West Virginia, which I used for my study. The second is in Australia. The goal was to see whether our instruments could really track them at such a high frequency and wide bandwidth. We observed source FRB 121102, which is known to emit these kind of bursts. But nobody had ever observed anything at such high frequencies. As luck would have it, we detected 15 such bursts in the first half hour. That motivated us and demonstrated to the scientific community that the equipment we possessed is up to the standard for detection of ET intelligence. If we demonstrate that we have the capability to detect such bursts, we can soon detect ET as well. We will also be exploring at higher frequencies. If we detect again, it will make things more interesting.
How probable is that the signals were emitted by an alien life form?
There are many theories out there. For one, we don’t understand the emission process which gives rise to such short, strong bursts. They are coming from so far away. So, some high-energy processes are happening at the source. ET intelligence could be one of the reasons. It can be argued that the bursts are microwave beacons used to propagate spaceships; we will detect them as FRBs.
I think the larger scientific community’s reluctance to accept this argument is for one very obvious reason: We find these FRBs all over the sky. Unless we have the same type of ETs spread across the universe, it is unlikely that they are the common explanation. If we consider it as natural phenomena, it could be a more plausible explanation as to why they are spread across the sky and not just one part. Still, we don’t know. We need to explore as many frequencies and timescales as possible.
You discovered these bursts from source FRB 121102. How difficult is it to detect other sources emitting such signals?
This is a rarest of the rare source. We have no other source which behaves like this. The search is hampered by the fact that, unlike the naked eye, a radio telescope can only scan a very small portion of the sky at a time. We will have to keep the telescope in motion, hoping to catch one of the sources in action.
In previous observations of the same source, we have seen that it goes through different phases: When it is active, it produces many such bursts in a very short time. When it is inactive, people have observed it for months and not discovered a single burst.
What are the other explanations for FRBs, if not aliens?
The neutron star or pulsar model is one which is more popular. In recent observations, we were able to localise the exact position of the source inside what they call a “star-forming region”. So people are suggesting that it is very easy for a young neutron star or a young pulsar to display this kind of a burst. Young pulsars do tend to have a large amount of energy loss.
Something about your journey from Gujarat to Berkeley.
I was born in a town named Botad. I did my engineering in my home state, but I was never an engineer. I was more interested in physics. In India, there is this trend that you become an engineer first and then you do what you want to do. I was more interested in physics, astronomy, formation of the universe and all that. I did my PhD from National Centre for Radio Astrophysics in Pune.
It was in Pune that I came across the Giant Metrewave Radio Telescope, a fascinating instrument to work with. I did my postdoc for a year and later landed a position in Berkeley. It was a dream come true for me, doing the work that I always dreamed of.
How possible is it that alien life forms exist?
If the possibility was zero, I wouldn’t be here. Take the number of stars in our galaxy. We now know that every star has a planet. Many of them could support life. If there is a chance for life to arise, it will definitely arise. If so, where will they be located? We are conducting a survey of nearby stars first, and we will push farther on.
