Note4Students
From UPSC perspective, the following things are important :
Prelims level: Black Hole and related terminologies
Mains level: Evidences confirming gravitational waves, relativity theory and black holes
Introduction
- Scientists have revealed new insights into a colossal black hole located 53 million light-years away, initially captured by the Event Horizon Telescope (EHT) in 2017.
- This groundbreaking achievement provided the first visual confirmation of the existence of black holes, validating a key prediction of Einstein’s theory of general relativity.
Key Findings by EHT
- The new data, obtained with improved telescope coverage and resolution, reiterated the previous discovery of the black hole’s ‘shadow’.
- The findings confirmed the presence of an asymmetric ring structure consistent with strong gravitational lensing effects.
- Observations indicated a stable ring formation process over time, with subtle changes suggesting variations in the magnetic field structure.
About Event Horizon Telescope (EHT)
| Description | |
| About | A large telescope array consisting of a global network of radio telescopes.
Uses Very-long-baseline interferometry (VLBI). Resolution of 25 micro-arc-seconds |
| Collaboration | International collaboration involving over 300 members and 60 institutions across 20 countries and regions |
| Launch Year | Initiated in 2009 |
| First Image Published | April 10, 2019 (First image of a black hole, M87*) |
| Objective | Observation of objects the size of a supermassive black hole’s event horizon |
| Key Targets | Black holes including M87* and Sagittarius A* (Sgr A*) |
| Recent Developments | First image of black hole (March 2021), first image of Sgr A* (May 12, 2022) |
| Reconstructive Algorithms | Includes CLEAN algorithm and regularized maximum likelihood (RML) algorithm |
| Scientific Implications | Verification of general relativity, measurement of black hole mass and diameter, study of accretion processes |
Back2Basics: Black Holes and Related Concepts
| Definition | |
| Black hole | A region in space where gravity is so strong that nothing, not even light, can escape from it. |
| Event horizon | The boundary surrounding a black hole beyond which nothing can escape its gravitational pull. |
| Singularity | A point within a black hole where gravity becomes infinitely strong and spacetime curvature becomes infinite. |
| Gravitational collapse | The process by which massive stars collapse under their own gravity to form black holes. |
| Schwarzschild radius | The radius of the event horizon of a non-rotating black hole. |
| Hawking radiation | Radiation emitted by black holes due to quantum effects near the event horizon, predicted by physicist Stephen Hawking. |
| Accretion disk | A rotating disk of matter that forms around a black hole as it pulls in surrounding gas and dust. |
| Supermassive black hole | A black hole with a mass millions or billions of times greater than that of the Sun, found at the center of most galaxies. |
| Quasar | A luminous object powered by an active galactic nucleus, thought to be fueled by the accretion of material onto a supermassive black hole. |
| Neutron star | A highly compact star composed primarily of neutrons, formed from the collapsed core of a massive star. |
| White dwarf | A small, dense star composed of electron-degenerate matter, formed from the remnants of a low to medium mass star. |
| Gravitational waves | Ripples in spacetime caused by the acceleration of massive objects, such as black holes or neutron stars. |
| Black Hole Information Paradox | The theoretical problem concerning the loss of information about the initial state of matter swallowed by a black hole, which contradicts the principles of quantum mechanics. |
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