Question

1. how can scientists detect a black hole if it does not emit

Explanation:

Scientists detect black holes (which don't emit light) by observing their gravitational effects. For example, a black hole's gravity can pull matter from a nearby star, forming an accretion disk that emits X - rays (detectable by telescopes). Also, gravitational lensing (bending of light from distant objects by the black hole's gravity) and the orbital motion of stars around an invisible, massive object (inferred to be a black hole) are used.

Answer:

Scientists detect a black hole (that does not emit light) by observing its gravitational effects: 1. Accretion Disk Emission: A black hole can pull matter from a nearby star into an accretion disk. Friction in this disk makes it hot, emitting X - rays detectable by X - ray telescopes. 2. Gravitational Lensing: The black hole’s gravity bends light from more distant objects. By observing distorted light from background stars/galaxies, the presence of a black hole can be inferred. 3. Orbital Motion of Nearby Stars: If a star orbits an invisible, extremely massive object (with properties matching a black hole’s expected mass/density), it suggests a black hole is there.