Discussion Overview
The discussion revolves around the existence and nature of super-massive black holes, particularly focusing on the implications of light behavior as objects approach the event horizon. Participants explore theoretical perspectives on black holes, their formation, and observational challenges related to their detection.
Discussion Character
- Exploratory
- Debate/contested
- Conceptual clarification
- Technical explanation
Main Points Raised
- One participant suggests that if a luminous body approaches a black hole, it becomes increasingly red-shifted and never appears to cross the event horizon from an external observer's frame of reference, questioning the existence of super-massive black holes.
- Another participant counters that the light emitted by the body does indeed fall into the black hole, and if one were to fall in, they would cross the event horizon without noticing anything unusual.
- A later reply emphasizes that the astronaut's perspective is limited, and while the object appears to approach the event horizon, it does cross it from its own frame of reference.
- Participants discuss the implications of seeing the light from an object falling into a black hole, noting that the last photons emitted before crossing the event horizon take an extended time to reach the observer, leading to confusion about the object's status.
- One participant proposes that black holes might emit highly red-shifted frequencies due to the residual light from consumed stars, suggesting this could be a method for detecting black hole candidates.
- Another participant asserts that black holes do not emit light and can only be inferred from changes in the sky over time, such as the disappearance of objects.
- Clarification is sought regarding the nature of light emitted by objects falling into black holes, with emphasis on the distinction between the object and the light observed from it.
Areas of Agreement / Disagreement
Participants express differing views on the implications of light behavior near black holes and the existence of super-massive black holes. There is no consensus on whether the inability to see an object crossing the event horizon implies that such black holes cannot exist.
Contextual Notes
The discussion highlights limitations in understanding the observational effects of black holes, particularly regarding the red-shifting of light and the nature of light emitted from objects falling into them. The dependence on different frames of reference adds complexity to the arguments presented.