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Recordedyearspace

A star is tracked through a complete close approach to the Galactic centre

Infrared monitoring resolved the orbit of the star S2 around the compact radio source Sagittarius A*, including its 2002 pericentre passage, establishing a period of about sixteen years and confining a mass of some millions of suns within a volume small enough to exclude every alternative except a black hole - a dense star cluster of that compactness would not be dynamically stable. It is the measurement that made the Galactic centre black hole the best-established case anywhere.

Observed — measured or witnessed, with the observation cited.

Subjects

Evidence

Partly verified — Core facts are sourced; some optional detail is deliberately absent.

Recorded on S2 - the star that measured the Galactic centre

  1. A star is tracked through a complete close approach to the Galactic centre
  2. The Event Horizon Telescope observes M87* and Sagittarius A*
  3. S2 passes pericentre and its light is measurably redshifted
  4. The orbit of S2 is shown to precess as general relativity predicts
  5. The Nobel Prize in Physics recognises black holes twice over
  6. The black hole at the centre of our own galaxy is imaged

Related

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