Recently, an international team of astronomers announced the confirmation of the existence of gravitational waves using pulsar observations. In these groundbreaking revelations, India’s Giant Metrewave Radio Telescope (GMRT), emerged as a critical component contributing to this scientific breakthrough. Among the six largest telescopes worldwide, GMRT played a pivotal role in providing evidence for these findings.
Key Discoveries
The discoveries included the first direct evidence supporting the continuous vibrations of space-time due to ultra-low frequency gravitational waves. The scientists also presented new data concerning the strength and frequency of these waves, congruent with theoretical predictions. Moreover, we are on the brink of discovering nanohertz gravitational waves. This discovery would usher in new possibilities for the study of galaxy evolution, cosmology, and underlying physics.
The Role of GMRT in Detecting Gravitational Waves
GMRT detects gravitational waves using pulsars, which are rapidly rotating neutron stars – the only accessible celestial clocks for humans. Pulsars emit steady pulses of radio waves that are helpful in measuring their rotation periods and distances with high precision. By observing Pulsar Timing Arrays (PTAs) distributed across the sky, GMRT can detect minor variations in their pulse arrival times caused by gravitational waves passing through the Earth-pulsar line of sight. This method is known as pulsar timing. GMRT is crucial to the PTA experiment due to its capability to provide unique data at low radio frequencies and high sensitivity.
About GMRT
Located near Narayangaon, Pune in India, GMRT is a low-frequency radio telescope consisting of an array of 30 fully steerable parabolic radio telescopes of 45-meter diameter. It’s operated by the National Centre for Radio Astrophysics, a segment of the Tata Institute of Fundamental Research, Mumbai. GMRT ranks among the largest and most sensitive radio telescope arrays globally at low frequencies. After significant upgrades in its receivers and electronics, it’s now known as the upgraded GMRT (uGMRT), boasting improved sensitivity and bandwidth.
Understanding Gravitational Waves
Gravitational waves are ripples in space-time triggered by violent and energetic processes in the Universe. Albert Einstein initially predicted their existence in his general theory of relativity in 1916.
Production of Gravitational Waves
The most potent gravitational waves are produced by catastrophic events such as colliding black holes, supernovae, and colliding neutron stars. Also, these waves can be created by the spin of non-spherical neutron stars and possibly remnants of gravitational radiation from the Big Bang.
Detection and Features of Gravitational Waves
Due to their weak interaction with matter, gravitational waves pose a challenge for detection. The first successful detection occurred in 2015 via an experiment with Laser Interferometer Gravitational Observatory (LIGO) detectors. Instruments like interferometers, such as LIGO, have been developed to detect gravitational waves by measuring minor disturbances in space-time.
UPSC Civil Services Examination
In the previous year examination, the understanding of gravitational waves was tested through questions related to blackhole mergers and the ‘Evolved Laser Interferometer Space Antenna (eLISA)’ project – a project aimed at detecting gravitational waves.
