Great Gig in the Sky

Radio astronomy,the field where GMRT is utilised,is the study of objects at radio frequencies. It arose less than a century ago with the discovery that the Milky Way emits radio waves. It is now known that several stars and galaxies are capable of radio emission,and new classes of astronomical objects have been discovered by analysing the emissions. It underwent an explosion after World War II. One of the pioneers was a talented amateur,Grote Reber,who spent two years mapping astronomical sources with a radio telescope he had constructed in his backyard. Todays scientists use increasingly large instruments located in the frigid South Pole or the arid Atacama Desert,and,of course,Pune,home to the GMRT.

Remarkably,the universe itself is a radio source; the faint background glow it emits is leftover energy from the Big Bang. The discovery of this radiation by American astronomers Arno Penzias and Robert Wilson substantiated the theory that the universe was born in a cosmic explosion of energy,earning them the Nobel Prize in 1978.

The GMRT has been used to study astronomical objects which emit strong radio waves,our own sun being the nearest example. A team of scientists used it to detect long wavelength radio emission from a colliding galaxy cluster. Such emissions had gone undetected before and the exciting implications of this finding were published in the scientific journal Nature.

The GMRT also enabled the study of more exotic astrophysical objects: pulsars,spinning stars that are the remnants of fiery supernovae. The earliest pulsar was named LGM-1. LGM stood for little green men,because its discoverers were so puzzled by the regularity of the emissions that they fancifully decided a race of green extraterrestrials was beaming signals to the universe. Or quasars,among the most distant and luminous objects in the universe. It has also been used to study a new dwarf dark galaxy a small object hypothesized to be a galaxy even though it contains very few stars; blazars,a class of quasars associated with super massive black holes that spit out streams of charged particles,at speeds that makes them some of the fastest known objects in the universe.

Astronomy has always been a relatively accessible science to the layman and boasted of many distinguished amateurs. The first person to discover comets,George Alcock,was an Englishman who memorized vast swathes of the night sky. The comet Hale Bopp,considered one of the most widely observed comets of the 20th century,owes half its name to Thomas Bopp,a factory manager from Arizona who was the first to spot it. Robert Evans,an Australian minister,holds the record for discovering the highest number of supernovae using a relatively simple telescope. The spectacular comet Shoemaker-Levy 9,which broke into a string of pearls before slamming into Jupiter,leaving the planet visibly bruised for months,was one among 22 comets discovered by Canadian writer and amateur astronomer David H. Levy. These are just a few amateurs who made significant discoveries in the field.

That high quality data generated by scientists using the GMRT will now be available to the public is,therefore,of great excitement. In a country like India,budding astronomers are arguably stymied by a lack of resources. This democratisation of science ensures that they are now free to explore the labyrinths of the telescope,where a landmark discovery may be lurking what better way to ignite scientific curiosity?

The GMRT scientists are handing us one of the coolest astronomical toys in the world. Want to come out and play?

scienceofourtimesexpressindia.com

The writer,a doctorate in biochemistry and molecular biology,lives in Bangalore