- #1
Phantasia
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Okay, these are some of my gravity questions. I found this site by searching for my own answers. Feel free to point me toward physics primers and introductory math texts, if you think it will help. I'm an avid reader of popular science texts, and am not afraid of equations, but I've never had the benefit of university coursework or instruction.
(1) Why don't we observe the aggregation of ring material due to gravity; i.e., how does one example of chaotic disruption of a system lead to a relatively even distribution and fanning of material into a classic ring object (thinking of the asteroid belt and the planetary rings), while another example quickly coalesces under gravity to form a single body (thinking of the planets themselves and the Earth impact moon formation theory)? I understand that epochal time is the field here, but it seems a system will move over that time scale toward aggregation or distribution. I guess the question depends upon knowing what comprises the asteroid belt. If it was a planet that disintegrated, how did the system distribute itself rather than coalesce? If it was never a planet, and the objects are merely the result of the best aggregation possible in its place, then how did rocky material form from dust?
(2) How does gravity work to keep orbiting systems stable? Equilibrium is not something we commonly experience. When we spin a gyroscope here on earth, it spins nicely for a while and then collapses under the influence of perturbations and… gravity. Looking at the universe, however, we see all systems pulled over time into equilibrium rather than chaotically careening and colliding, which seems counter to commonsense and one of those laws of thermodynamics. The question, restated: how can gravity work to create stable orbiting systems, when even one perturbation should disrupt stable orbits to cause rapid decay, and there are innumerable perturbations on similar or larger scales (from other systems, the galactic system and the cosmological system)?
(3 - an easy one) If we could evacuate a perfectly spherical person-sized chamber capable of supporting life exactly in the center of the Earth's mass, and I were to be inside that chamber, what could be said about the effects of gravity there? Let's say that the sphere has an interior space four meters in diameter, that my height is two meters. If I curled up into a ball and was placed in the center of the sphere (and therefore the center of Earth's mass and gravity), would I float there, pulled equally in all directions? Would I experience weight if I were standing on the interior surface of the sphere, with my head roughly in the center of it? What if the sphere were 100 meters in diameter? How could I calculate these values and put them into a table?
(4) Why doesn't the expansion of space disrupt orbiting systems? If the expansion does disrupt them, then why are there any orbiting systems at all? (Thinking maybe matter, therefore mass, therefore gravity, expands with space?)
(5) Can we observe the gravitational tidal forces of our own galaxy? As Earth rotates, one side is facing the bulk of the galactic mass, so why aren't these tidal forces of our own galaxy prominently observed when the gravitational field of galaxies is strong enough to hold the cosmos together?
I understand that gravity is poorly understood, and that I'm the umpteen-millionth person to chime in with questions, but I'm just looking for clues, not the meaning of life. I also saw that multiple questions probably should be posted in multiple threads, but that will be difficult for follow-up, I think, so I give you my apologies. Thanks in advance for helpful replies.
(1) Why don't we observe the aggregation of ring material due to gravity; i.e., how does one example of chaotic disruption of a system lead to a relatively even distribution and fanning of material into a classic ring object (thinking of the asteroid belt and the planetary rings), while another example quickly coalesces under gravity to form a single body (thinking of the planets themselves and the Earth impact moon formation theory)? I understand that epochal time is the field here, but it seems a system will move over that time scale toward aggregation or distribution. I guess the question depends upon knowing what comprises the asteroid belt. If it was a planet that disintegrated, how did the system distribute itself rather than coalesce? If it was never a planet, and the objects are merely the result of the best aggregation possible in its place, then how did rocky material form from dust?
(2) How does gravity work to keep orbiting systems stable? Equilibrium is not something we commonly experience. When we spin a gyroscope here on earth, it spins nicely for a while and then collapses under the influence of perturbations and… gravity. Looking at the universe, however, we see all systems pulled over time into equilibrium rather than chaotically careening and colliding, which seems counter to commonsense and one of those laws of thermodynamics. The question, restated: how can gravity work to create stable orbiting systems, when even one perturbation should disrupt stable orbits to cause rapid decay, and there are innumerable perturbations on similar or larger scales (from other systems, the galactic system and the cosmological system)?
(3 - an easy one) If we could evacuate a perfectly spherical person-sized chamber capable of supporting life exactly in the center of the Earth's mass, and I were to be inside that chamber, what could be said about the effects of gravity there? Let's say that the sphere has an interior space four meters in diameter, that my height is two meters. If I curled up into a ball and was placed in the center of the sphere (and therefore the center of Earth's mass and gravity), would I float there, pulled equally in all directions? Would I experience weight if I were standing on the interior surface of the sphere, with my head roughly in the center of it? What if the sphere were 100 meters in diameter? How could I calculate these values and put them into a table?
(4) Why doesn't the expansion of space disrupt orbiting systems? If the expansion does disrupt them, then why are there any orbiting systems at all? (Thinking maybe matter, therefore mass, therefore gravity, expands with space?)
(5) Can we observe the gravitational tidal forces of our own galaxy? As Earth rotates, one side is facing the bulk of the galactic mass, so why aren't these tidal forces of our own galaxy prominently observed when the gravitational field of galaxies is strong enough to hold the cosmos together?
I understand that gravity is poorly understood, and that I'm the umpteen-millionth person to chime in with questions, but I'm just looking for clues, not the meaning of life. I also saw that multiple questions probably should be posted in multiple threads, but that will be difficult for follow-up, I think, so I give you my apologies. Thanks in advance for helpful replies.