What groundbreaking discoveries has Reinhard Genzel made in astrophysics?

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Discussion Overview

The discussion revolves around the nature of time as it relates to black holes, particularly focusing on the implications of time dilation and the event horizon. Participants explore concepts such as coordinate time, proper time, and the behavior of objects falling into black holes from various observational perspectives. The conversation touches on theoretical constructs in astrophysics and the implications of these ideas for understanding black holes.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants assert that "our" time is an optical illusion and not meaningful for local events, while others argue that it serves as a cosmic time that can be measured universally.
  • A participant questions whether anything has ever crossed into a black hole in "our" time, suggesting that all events beyond the event horizon remain in the future of "our" time.
  • There is a discussion about the nature of the event horizon and how it can expand to enclose objects approaching a black hole, with some participants expressing uncertainty about the clarity of this explanation.
  • Participants discuss the concept of coordinate time and proper time, with some emphasizing that proper time is the only meaningful measure for an observer falling into a black hole.
  • There are inquiries about the Kruskal–Szekeres coordinates and their implications at the event horizon, with requests for clarification on the mathematical aspects involved.
  • One participant expresses skepticism about the idea of a singularity being a theoretical construct, prompting further exploration of the definitions and implications of singularities in general relativity.
  • Questions arise regarding the existence of mass inside black holes and the relationship between mass and the event horizon.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of time in relation to black holes, the implications of coordinate systems, or the existence and nature of singularities. Multiple competing views remain, and the discussion is characterized by uncertainty and differing interpretations of theoretical concepts.

Contextual Notes

Participants express various assumptions about time, the nature of black holes, and the mathematical frameworks used to describe them. There are unresolved questions regarding the implications of these concepts and the definitions used in the discussion.

Who May Find This Useful

This discussion may be of interest to those studying general relativity, black hole physics, or the philosophical implications of time in astrophysics.

  • #31
Here is a credible source:

https://www.youtube.com/watch?v=ZDxFjq-scvU

http://www.mpe.mpg.de/ir/GC

Reinhard Genzel:

Studied physics at the University of Freiburg and the University of Bonn where he did his PhD in 1978[2] and, in the same year, his PhD thesis on radioastronomy at the Max Planck Institute for Radio Astronomy.[2] He then worked at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. He then was a Miller Fellow from 1980 until 1982, and also Associate and Full Professor in the Department of Physics at the University of California, Berkeley from 1981. He became Scientific Member of the Max-Planck-Gesellschaft in 1986, and director at the Max Planck Institute for Extraterrestrial Physics in Garching and lectured at Ludwig-Maximilians-Universität München where he has been honorary Professor since 1988. Since 1999 he has also a joint appointment as Full Professor at the University of California, Berkeley.[2] He also sits on the selection committee for the Astronomy award, given under the auspices of the Shaw Prize. Genzel is fluent in German and English.

Work
Reinhard Genzel studies infrared- and submillimetre astronomy, and he and his group are active in developing front-line ground- and space-based instrumentation for their astronomy research. He and his group were the first to track the motions of stars at the centre of the Milky Way and show that they were orbiting a very massive object, probably a black hole.[3] Genzel is also active in studies of the formation and evolution of galaxies.
 

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