Recently, an international team of astronomers announced scientific evidence confirming the presence of gravitational waves using pulsar observations. India’s Giant Metrewave Radio Telescope (GMRT) was among the world’s six large telescopes that played a vital role in providing this evidence.
GS III: Science and Technology
Dimensions of the Article:
- Giant Metrewave Radio Telescope (GMRT)
- Gravitational waves
Giant Metrewave Radio Telescope (GMRT)
- GMRT is a low-frequency radio telescope used for investigating various radio astrophysical phenomena, ranging from nearby solar systems to the edge of the observable universe.
- It is located at Khodad, situated 80 km north of Pune, and is operated by the National Centre of Radio Astrophysics (NCRA).
- The NCRA is a part of the Tata Institute of Fundamental Research (TIFR) based in Mumbai.
- GMRT is a project of the Department of Atomic Energy (DAE) and operates under the Tata Institute of Fundamental Research (TIFR).
- The telescope consists of 30 fully-steerable dish-type antennas, each with a diameter of 45 meters, spread over a 25-km region.
- Presently, GMRT holds the distinction of being the world’s largest radio telescope operating at meter wavelengths.
The objectives of GMRT include:
Detecting highly redshifted spectral lines of neutral Hydrogen:
- GMRT aims to detect the faint signals of neutral Hydrogen in its highly redshifted state.
- This can provide insights into the early phase of the Universe when proto-clusters or protogalaxies were forming before condensing into galaxies.
- Redshift, in this context, refers to the change in the wavelength of the signal based on the object’s location and movement.
Studying rapidly-rotating Pulsars in our galaxy:
- GMRT is also used to search for and study pulsars, which are rapidly rotating neutron stars with extremely high densities.
- Pulsars emit regular radio beams that flash towards the Earth, similar to how a lighthouse emits beams.
- By studying pulsars, scientists can gain valuable information about their properties, behavior, and the surrounding environment.
Significance of GMRT
The significance of GMRT lies in its unique capabilities and contributions to various fields of astrophysics. Some key points highlighting its significance are:
Wide frequency bandwidth:
- GMRT operates within the frequency range of 100 MHz to 1,500 MHz, allowing it to observe a broad range of radio emissions and signals from celestial objects.
- This wide frequency coverage enables the study of diverse astrophysical phenomena.
- GMRT is highly sought-after by scientists from more than 30 countries, demonstrating its recognition and importance in the global scientific community.
- Its capabilities and data are valuable for researchers worldwide.
Tracing the evolution of galaxies:
- GMRT plays a crucial role in understanding the evolution of galaxies over cosmic time.
- By detecting and analyzing the radio emissions from atomic hydrogen (21 cm wavelength), GMRT enables scientists to trace the distribution and behavior of neutral gas in galaxies.
- This gas is essential for star formation and provides insights into the processes involved in galaxy evolution.
Studying distant galaxies:
- GMRT’s large collecting area and sensitivity allow for the detection of faint radio signals emitted by distant galaxies.
- This is particularly important when studying the 21 cm emission from atomic hydrogen in distant galaxies, which is otherwise challenging to detect.
- GMRT’s data contributes to our understanding of galaxies across different cosmological periods.
Wide range of astrophysical studies:
- GMRT’s capabilities extend beyond galaxy evolution.
- Its large collecting area and frequency coverage make it a useful instrument for studying various astrophysical phenomena.
- This includes investigating solar and planetary radio emissions, studying the relationship between solar activity and disturbances in the interplanetary medium, and exploring other frontier areas of astrophysics.
- Gravitational waves are space-time ripples resulting from violent and energetic processes in the Universe.
- Albert Einstein predicted their existence in 1916 through his general theory of relativity.
- According to Einstein’s mathematics, massive accelerating objects, such as orbiting black holes or neutron stars, disrupt space-time, causing undulating waves to propagate in all directions.
- These waves carry information about their origins and provide insights into the nature of gravity.
- Massive objects like neutron stars or black holes orbiting each other are sources of gravitational waves.
Production of Gravitational Waves
- Cataclysmic events, including colliding black holes, supernovae, and colliding neutron stars, generate the strongest gravitational waves.
- Gravitational waves can also be produced by non-spherical rotating neutron stars and possibly remnants of gravitational radiation from the Big Bang.
- Gravitational waves are challenging to detect due to their weak interaction with matter.
- Interferometers, highly sensitive instruments, have been developed to detect these waves.
- The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a well-known example that achieved the first direct detection of gravitational waves in 2015.
-Source: Indian Express