The hole picture. (arXiv:1910.04173v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Cardoso_V/0/1/0/all/0/1">Vitor Cardoso</a>

Because of the very definition of black holes — no light escapes them and
falling objects get infinitely faint when approaching — it is impossible to
ever prove that they exist. However, electromagnetic and gravitational-wave
observatories have now `seen’ black holes. Datasets from these observations,
released in 2019 and late 2018, give important hints about the environment,
origin and growth of black holes.

Because of the very definition of black holes — no light escapes them and
falling objects get infinitely faint when approaching — it is impossible to
ever prove that they exist. However, electromagnetic and gravitational-wave
observatories have now `seen’ black holes. Datasets from these observations,
released in 2019 and late 2018, give important hints about the environment,
origin and growth of black holes.

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