Fast Radio Burst: A two-decade mystery about to end?

“Look at the sky. We are not alone. The whole universe is friendly to us and conspires only to give the best to those who dream and work.”
-A.P.J. ABDUL KALAM

During the late 1990s cosmologists made predictions about the quantity of ordinary matter that should be present in the universe. They estimated that about 5% should be regular stuff with a mixture of dark matter and dark energy. The sum of ordinary matter was only up to half of 5% which was supposed to be in the universe. The “missing baryon” issue was a perturbing mystery for over two decades.

What is “Missing Baryon” issue ?

In the late 1970s, the dark matter was being suspected as an unknown type of matter which exists to explain the gravitational patterns in space. Together with the baryonic matter, they make up most of the matter in the universe and their ratio was unknown. Baryon comprises protons and neutrons, which are building blocks of the ordinary matter present in the Universe.

For the estimation of the quantity of baryons, three scientists from the University of California used the ratio of heavy Hydrogen nuclei (i.e. Hydrogen with an extra neutron to normal Hydrogen) in the year 1997. Later a direct measure of baryons was done through a census of stars, galaxies, and gas within and around them which actually added up to only half of the predicted 5% by a trio of cosmologists. This paved the way to missing baryon issue as it was against the Law of Nature (Matter can neither be created nor be destroyed). Either the matter did not exist or it was hiding out somewhere was the only possible explanation for this.

Doomed Exploration :

An extensive investigation was done by astronomers across the world. The first clue was that the missing matter was hiding in low density, million-degree hot plasma that spread throughout the Universe and was termed as “Warm-Hot Intergalactic Medium”(WHIM). Having a glance at tiny temperature fluctuations in Universe’s Cosmic microwave background which was the left over radiation from Big Bang had confirmed the prediction of Baryon in 2001. Many cosmologists and astronomers have been impatiently searching the evidences for over the past 20 years.

Unforeseen solution in FRB :

In 2007, at the University of West Virginia, an astronomer named Duncan Lorimer did a fortuitous discovery of cosmological phenomena known as Fast Radio Burst (FRB). FRBs are brief, high energetic pulses of radio emissions and appear as flashes of energy which come from random directions in sky lasting for just milliseconds. According to Dr.Jean-Pierre Macquart from the Curtin University of International Centre for Radio Astronomy Research (ICRAR), the FRBs travel for billions of years and occasionally pass through gases, theorized WHIM causing dispersion. The radio waves get slowed down while passing through matter. Dispersion has slowed the radiation with longer wavelengths, that they arrive nearly a second later than shorter wavelengths and it can be observed just like the colour separation in a prism. The timing of arrival of radiation with different wavelengths will give an account of how much material the burst has passed through on its journey.

Profound Technical Innovation :

The discovery of FRBs and its localisation to distant galaxies had boosted the urge to solve the mystery. The innovation of CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope had become the key to success. Ryan Shannon, Associate Professor from Swinburne University of Technology describes ASKAP as a wide field of view. That is about 60 times the size of a full moon with a high-resolution image. So the burst can be captured with relative ease and can pinpoint locations to the host galaxies with incredible precision. As the burst arrives the telescope, a live-action replay is recorded within a fraction of a second. Also, they have discovered the equivalent of the Hubble-Lemaitre Law for galaxies especially for FRB’s.

The Hubble-Lemaitre Law says that, farther the galaxy, the faster they are moving away from earth(velocity is proportional to distance). The velocity of galaxy is determined by its redshift. ASKAP is a precursor of future Square Kilometre Array (SKA) Telescope and SKA will enable us to observe large numbers of FRB. It is a greater possibility to study previously invisible structures in Universe.

The eminent writer Paulo Coelho in his famous work “The Alchemist” says; When you want something, all the universe conspires in helping you to achieve it. Let’s hope for a better technology which can reveal the mysteries of the Universe.

Watch the video to know more about FRB.