In a significant scientific breakthrough, an international team of astronomers has recently provided scientific evidence confirming the presence of gravitational waves through pulsar observations. India’s Giant Metrewave Radio Telescope (GMRT) was among the six large telescopes worldwide that played a crucial role in obtaining this evidence. This discovery opens up new possibilities for studying the Universe and deepening our understanding of gravitational waves.
Understanding Pulsar Observations:
- Pulsars as Cosmic Clocks: Pulsars are rapidly spinning neutron stars that emit regular radio signals, often referred to as cosmic clocks. These signals are seen as bright flashes from Earth and offer precise timing, making them valuable objects for scientific study and unraveling the mysteries of the Universe.
- Creating an ‘Imaginary’ Gravitational Wave Detector: To detect gravitational wave signals, scientists utilize ultra-stable pulsar clocks scattered throughout the Milky Way galaxy, forming a galactic-scale gravitational wave detector. By analyzing the signals from these pulsars, researchers can study the effects of gravitational waves on their arrival at Earth.
Detection of Gravitational Waves:
- Time Aberration in Pulsar Signals: The recent studies conducted by the Indian Pulsar Timing Array (InPTA) and European Pulsar Timing Array (EPTA) observed a time aberration in the signals emitted by pulsars. This time aberration indicated the presence of gravitational waves influencing the arrival of these signals at Earth.
- Nano-hertz Gravitational Waves: The observed signals, known as nano-hertz signals, represent ultra-low frequency gravitational waves. These waves are believed to originate from the collision of massive black holes, millions of times heavier than our Sun. The resulting ripples, called nano-hertz gravitational waves, create a consistent humming in the Universe, detectable using powerful radio telescopes on Earth.
Role of Giant Metrewave Radio Telescope (GMRT):
The GMRT, a low-frequency radio telescope located in India, played a crucial role in the detection of gravitational waves through pulsar observations.
- Investigating Radio Astrophysical Problems: GMRT is designed to investigate various radio astrophysical phenomena, ranging from nearby solar systems to the edge of the observable universe. Its capabilities enable astronomers to explore a wide range of radio astrophysical problems, including the detection of gravitational waves.
Understanding Gravitational Waves:
- Ripples in Space-Time: Gravitational waves are ripples in space-time caused by violent and energetic processes in the Universe. These waves were first predicted by Albert Einstein in 1916 as a consequence of his general theory of relativity.
- Disruption of Space-Time by Massive Objects: According to Einstein’s mathematics, massive accelerating objects, such as black holes or neutron stars orbiting each other, disrupt space-time, causing waves of undulating space-time to propagate outward from the source.
- Carriers of Information: Gravitational waves carry valuable information about their origins and provide insights into the nature of gravity itself. By studying these waves, scientists can gain a deeper understanding of the Universe and its fundamental principles.
