query: How can we see black holes form and gain mass if nothing can cross a horizon (when viewed from our reference frame)?
positive_passages.docid: 7809
positive_passages.text: How can anything ever fall into a black hole as seen from an outside observer?
negative_passages.docid: 61095
negative_passages.text: When does a singularity start to exist during a black hole formation?
negative_passages.docid: 143244
negative_passages.text: How can black holes be so dense?
negative_passages.docid: 158777
negative_passages.text: How exactly does black hole evaporate?
negative_passages.docid: 9643
negative_passages.text: Black holes are transparent?
negative_passages.docid: 124006
negative_passages.text: Redshift of merging black holes
negative_passages.docid: 18038
negative_passages.text: Can we detect gravitational waves generated from inside the event horizon of a black hole?
negative_passages.docid: 19662
negative_passages.text: Can a black hole be explained by Newtonian gravity?
negative_passages.docid: 114449
negative_passages.text: Gravitational slingshot of light using a black hole/massive object
negative_passages.docid: 56773
negative_passages.text: Fighting a black hole: Could a strong spherical shell inside an event horizon resist falling in to the singularity?
negative_passages.docid: 33056
negative_passages.text: Why will data from a black hole solve the gravity problem?
negative_passages.docid: 90481
negative_passages.text: 3D donuts and the centre of a black hole
negative_passages.docid: 41296
negative_passages.text: Can a single particle create a black hole?
negative_passages.docid: 85078
negative_passages.text: Why must a singularity form inside a black hole?
negative_passages.docid: 102940
negative_passages.text: Why don't the black holes appear black in color in images of galaxies taken from HST?
negative_passages.docid: 47968
negative_passages.text: Thought Experiment - Poking a stick across a Black Hole's Event Horizon
negative_passages.docid: 136949
negative_passages.text: Can a black hole be formed by electromagnetic radiation?