# If rotation has nothing to do with gravity, why do astronomers always link swirling dust and gas to stellar evolution?

All my life I was taught in school that we have gravity because the earth spins. Now I know that is not true. Online academics were baffled why anyone thought so. I can only say that's what they said in school.

But if gravity is more mass and everything in the universe has some gravitational "pull", then why do astronomers always use spinning and whirling dust and gas as a way to explain stellar evolution? They make it sound like the spinning around created the gravity to form the mass and the bigger it got the more it spun and made more gravity.

• Spinning a spaceship generates centrifugal force which produces "gravity" for objects inside although it's just centrifugal force. Sorry about the confusion. Also, check this link: astronomy.stackexchange.com/questions/39893/… Dec 3, 2020 at 15:44
• Never heard before that rotation generale gravity I doubt you got that from any school. Except for artificial kind of like in centrifuges, as you mentioned it the last sentences. In short, matter collapsing under gravitational attraction combined with density fluctuations and conservation of momentum causes dust and gas to swirl and rotate. Dec 4, 2020 at 10:51
• @Alchimista I was there. They taught it. Dec 4, 2020 at 16:48
• Why was it downvoted? Dec 4, 2020 at 16:48
• @PierrePaquette most likely it was "if gravity stops we'll fly because of earth spinning". The point I was making it is not that I don't believe OP or you, but not to confuse "school" with school programme or individual teacher. Of course everithing is possibile. Probably they still teach the "other" bulge of tide as due to rotation, which can be true but not in the way they said. But the example brought in by OP and you really sound unbelievable :) Dec 5, 2020 at 8:48