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Gigantic Cosmic Shockwave
A research published in Astronomy & Astrophysics (7 Feb, 2022) gives fascinating insight into a cosmic phenomena in space that is consequence of an event that happened billions of years ago and led to formation of galaxy cluster known as Abell 3667. An international team of scientists studied the largest cosmic shockwave visible from Earth. (Maybe, there are even bigger ones still to be found!) This gigantic shockwave is spread across 6.5 million light years.
For comparison, it is much vast than our galaxy Milky Way which contains 100 to 400 billion stars. Milky Way is about 100,000 light-years across. And what to say of the Solar System of which Earth is a member? The diameter of the Solar System is a mere 287.46 billion km (=0.0304 light years)
Space is vast and incomprehensible, truly infinite. It holds infinite secrets and even when we think that science has progressed and people speak of post-modern world, the astounding phenomena contained in the universe always surprises. It even makes us think, how the Earth continues to exist. In the vast expanse of huge stars and planets moving about in their trajectories, Earth looks like a paradise, while we the intelligent beings, in our little spaces consider ourselves powerful to fight, kill, hate and keep spreading many other negatives. Our inconsequentiality as human race is truly miniscule when seen in the context of the vast infinite space.
When I read about this research, I was reminded of the famous Astrophysicist Carl Sagan who said:
Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam…
Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space
The Gigantic Shockwave :
Gigantic or colossal shockwave occurs when clusters of galaxies collide and such intensity of collision and the energy released can even be compared with the Big Bang. It’s not just collision of two galaxies, but collision of cluster of galaxies. Just to remember, one galaxy like our Milky Way contains 100 to 400 billion stars. And a “galaxy cluster” can contain thousands of galaxies.
Such cosmic phenomena where clusters of galaxies collided – their remnants are detected using radio telescopes.
It is estimated that this collision took place more than a billion years ago between two massive galaxy cluster that ultimately formed the galaxy cluster known as Abell 3667.
This research on shockwave was detected and the research done by using MeerKAT which is a radio telescope located in the Northern Cape of South Africa and contains 64 antennas.
Moreover, The shock waves are still propagating through the newly formed galaxy cluster (Abell 3667) at the speed of 1500 km/second. According to the scientists, the shock waves act as giant particle accelerators that accelerate electrons to speeds close to the speed of light. When these fast electrons cross a magnetic field they emit the radio waves that we see.
The purpose / context of research:
During their lifetimes, galaxy clusters grow through the accretion of matter from the filaments of the large-scale structure and from mergers with other clusters. These mergers release a large amount of energy into the intracluster medium (ICM) through merger shocks and turbulence. These phenomena are associated with the formation of radio sources known as radio relics and radio halos, respectively. Radio relics and halos are unique proxies for studying the complex properties of these dynamically active regions of clusters and the microphysics of the ICM more generally.
Research published in Astronomy & Astrophysics manuscript no. meerkat˙3667. Published by EDP Sciences, to be cited as https://doi.org/10.1051/0004-6361/202142658
It is equally interesting to note that the galaxy cluster Abell 3667 is around 700 million light years away. For comparison of distance, the closest known galaxy to us is the Canis Major Dwarf Galaxy which is about 25,000 light years away from us.
Image Credit: Media Release by SARAO (South African Radio Astronomy Observatory)