query: What prevents galaxies from collapsing towards the galactic center?
positive_passages.docid: 3617
positive_passages.text: Why doesn't the Moon fall onto the Earth?
negative_passages.docid: 84266
negative_passages.text: What keeps lightsabers from going through each other?
negative_passages.docid: 90481
negative_passages.text: 3D donuts and the centre of a black hole
negative_passages.docid: 96744
negative_passages.text: Under which conditions do two moving bodies start orbiting each other around their center of mass?
negative_passages.docid: 108623
negative_passages.text: Is there a black hole in the centre of the Milky Way?
negative_passages.docid: 3767
negative_passages.text: Constrained stars and bars.
negative_passages.docid: 27365
negative_passages.text: Why can't light escape from a classical black hole?
negative_passages.docid: 107971
negative_passages.text: Hubble's law and conservation of energy
negative_passages.docid: 10362
negative_passages.text: Does the universe have a center?
negative_passages.docid: 41170
negative_passages.text: Why is gravity so hard to unify with the other 3 fundamental forces?
negative_passages.docid: 90028
negative_passages.text: Formation of supermassive black holes
negative_passages.docid: 123415
negative_passages.text: Spacial curvature and expanding space
negative_passages.docid: 13221
negative_passages.text: How would normal matter behave under conditions found in the core of the sun?
negative_passages.docid: 73673
negative_passages.text: What is gravity and what causes objects to act against it?
negative_passages.docid: 95674
negative_passages.text: Expansion of the Universe, will light from some galaxies never reach us?
negative_passages.docid: 68288
negative_passages.text: Anti-Matter Black Holes
negative_passages.docid: 137885
negative_passages.text: Why doesn't a star's core cool down when it expands as a red giant?