Astrophysics and Cosmology

The statement is historically accurate. Einstein's special relativity (1905) challenged the widely-held belief in luminiferous ether as the medium for electromagnetic wave propagation. The scientific community's resistance to abandoning the ether concept was indeed one factor that delayed relativity's widespread acceptance for several decades.

Schumann resonance refers to the extremely low frequency electromagnetic resonances in Earth's atmosphere, primarily at 7.83 Hz. These are global electromagnetic resonances generated by lightning activity in the cavity between Earth's surface and the ionosphere.

According to special relativity, as an object approaches the speed of light, time dilation causes time to slow down relative to a stationary observer. At the speed of light itself, time would theoretically stop for the traveling person. This means they wouldn't age at all from their own perspective.

Black holes appear black because their gravitational pull is so strong that they absorb all light and reflect nothing. No light can escape from within the event horizon, making them completely invisible against the darkness of space.

Black hole movement can be tracked by measuring mass density variations in space and by observing the orbital patterns of stars around invisible points. Scientists have used stellar motion around Sagittarius A* to confirm the supermassive black hole at our galaxy's center.

The event horizon is the boundary surrounding a black hole beyond which nothing can escape, not even light. It's the point of no return for any matter or radiation. Options B, C, and D are incorrect - the event horizon is not about reflection, refraction, or 'nothing happening'.

Gravitational lensing is the bending of light due to gravitational effects from massive objects, not just black holes. It occurs when a massive body curves spacetime, causing light to follow a curved path. Option B is correct - it's about gravity's effect on light. Options A, C, and D are incorrect as they mention magnetic fields or restrict it to black holes.

From the perspective of an observer on Earth, someone falling into a black hole appears to slow down as they approach the event horizon due to gravitational time dilation, and seems to take infinite time to cross it. This is called infinite redshift. Option B correctly describes this relativistic effect. Options A, C, and D are incorrect.

Subrahmanyan Chandrasekhar's work on stellar evolution led to the Chandrasekhar limit, which states that stars above a certain mass must collapse into black holes. This fundamental contribution established him as the discoverer of black hole theory.

A black hole's ability to trap all radiation, including light, is due to its extremely high density within a small volume. This creates such intense gravitational force that not even electromagnetic radiation can escape its gravitational pull. The size can vary, and low density would not produce this effect.

General relativity incorporates gravity as spacetime curvature, while special relativity (1905) assumes flat spacetime and no gravity. Electromagnetism is in both theories, eclipses were tests, and quantum theory is separate.

E=mc² emerges from special relativity (1905), relating mass and energy. General relativity (1915) deals with gravity. Blackbody radiation and Planck's law are quantum phenomena, though connected to Einstein's other work.

Black holes are detected through multiple methods: gravitational effects on nearby stars and gas (accretion disks), X-ray emissions from superheated matter, and gravitational waves from mergers. Optical observations can detect indirect effects but black holes don't emit visible light. Using a prism for spectrum analysis is primarily a laboratory technique for studying light, not a method for black hole detection.

A black hole is formed when a massive star collapses under its own gravity, creating a region where spacetime is so extremely curved that the escape velocity exceeds the speed of light. The boundary of no return is called the event horizon, and nothing including electromagnetic radiation can escape from within it. This makes black holes invisible to direct observation, though we can detect them through their gravitational effects on nearby matter.