MooNiNite Posted June 9, 2017 (edited) A gravity hill, simply put, is a sloped area where gravity seems to be faltering: causing objects to rise against the slope. http://minethehive.com/2017/06/scrutiny-gravity-hills-and-localized-distortions/ Edited June 9, 2017 by MooNiNite 4 Share this post Link to post Share on other sites
MooNiNite Posted June 9, 2017 "Not all of these places are illusions, but rather, actual inconsistencies in the direction gravity pulls. Any large mountain does this as well. On the side of a mountain gravity does not pull in the same direction as it does off the mountain. It pulls more in the direction of the mountain, rather than in the direction of earth's core. There are just some places on earth where this difference is extreme." Possibly electromagnetism field is being distorted and causing gravity to nullify. 1 Share this post Link to post Share on other sites
Marblehead Posted June 9, 2017 Yes, these things are facts of nature. I know of one in Michigan and also one in Oregon. They defy our common understanding of gravity. And yes, it has to do with the make-up of the earth in those areas. 1 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 This one doesn't even pretend to be based on anything science-y. Those who bicycle in the mountains know well how easily the "eye" is deceived about what is "downhill." 2 Share this post Link to post Share on other sites
MooNiNite Posted June 9, 2017 3 hours ago, Brian said: This one doesn't even pretend to be based on anything science-y. Those who bicycle in the mountains know well how easily the "eye" is deceived about what is "downhill." It is interesting, but the "carpenter test" doesnt seem like a valid way to test. Share this post Link to post Share on other sites
Brian Posted June 9, 2017 Here's a relevant question -- what is "down"? 1 Share this post Link to post Share on other sites
rene Posted June 9, 2017 4 minutes ago, Brian said: Here's a relevant question -- what is "down"? Down - is where my face ends up when I trip and do random gravity checks. 3 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 14 minutes ago, WuDao said: Down - is where my face ends up when I trip and do random gravity checks. Yes! 1 Share this post Link to post Share on other sites
Marblehead Posted June 9, 2017 Would you consider rather than the word "down" the phrase "toward the center"? 2 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 17 minutes ago, Marblehead said: Would you consider rather than the word "down" the phrase "toward the center"? We often think of it that way, don't we? They are not necessarily synonymous, though. "Down" deals with forces and "toward the center" is geometry-based. If we are talking about gravity, the former is really more appropriate. Share this post Link to post Share on other sites
rene Posted June 9, 2017 Which one would best describe the point of strongest pull? Share this post Link to post Share on other sites
Brian Posted June 9, 2017 (edited) 14 minutes ago, WuDao said: Which one would best describe the point of strongest pull? You mean direction? Depends on the source of the force. In general, if we are talking about large, massive objects and the gravitational force between them, we often treat the objects as point masses centered at the "center of mass" (a summation of discrete masses and their distribution in space) but this is really just an approximation -- a very good approximation in most cases but... Soooo... The apparent "pull" would generally seem be along the line connecting the two centers of mass -- assuming the scenario is such that the approximation is valid. Edited June 9, 2017 by Brian 1 Share this post Link to post Share on other sites
MooNiNite Posted June 9, 2017 6 hours ago, Brian said: This one doesn't even pretend to be based on anything science-y. Those who bicycle in the mountains know well how easily the "eye" is deceived about what is "downhill." So you have been on a hill that looked down but was really up? I find that hard to believe. Share this post Link to post Share on other sites
rene Posted June 9, 2017 29 minutes ago, Brian said: You mean direction? Depends on the source of the force. In general, if we are talking about large, massive objects and the gravitational force between them, we often treat the objects as point masses centered at the "center of mass" (a summation of discrete masses and their distribution in space) but this is really just an approximation -- a very good approximation in most cases but... Soooo... The apparent "pull" would generally seem be along the line connecting the two centers of mass -- assuming the scenario is such that the approximation is valid. So then neither 'down' nor 'towards the center' aptly describes. You started this, you know, asking what is 'down'. And 'down' is what you get off a duck. 1 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 13 minutes ago, MooNiNite said: So you have been on a hill that looked down but was really up? I find that hard to believe. Most definitely. I actually made money off one -- I was driving with a friend along a stretch of road, a steep incline with a dip in it that was almost flat but still slightly uphill. It looked like it was downhill but it wasn't. 2 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 8 minutes ago, WuDao said: So then neither 'down' nor 'towards the center' aptly describes. You started this, you know, asking what is 'down'. And 'down' is what you get off a duck. If you are talking gravity as perceived by an observer (which I think we are), "down" is the proper word. "Down" is the direction I feel the force of gravity pull me. 2 Share this post Link to post Share on other sites
MooNiNite Posted June 9, 2017 I find it hard to believe that your explanation is sufficient. But maybe i just need to get out more. 1 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 Just to expand on this a bit more... "Down" is the direction I feel the force of gravity pull me. This is typically but not necessarily (and not always) along the line connecting the "center of mass" of my body to the center of mass the Earth. "Down" is a relative and perceptual thing, though. Remember that gravity is a force and the effect of that force upon a massive body (whether a particle or a person or a planet) is to accelerate that body in the direction of greatest decrease in potential. We perceive gravitational force as "weight" but we also perceive other accelerative forces as weight, too, and we -- perceptually --don't distinguish between them. Turns out it isn't just that we don't distinguish between them but that the distinction is illusory. This was a pivotal element of special relativity -- the idea that an accelerating elevator and the pull of a planet are indistinguishable. So, gravity is the attractive force between masses (which, according to relativity, is a product of the distortion of the fabric of space-time, but I digress) and it acts along the line(s) connecting the masses. The magnitude of the force is proportional to the magnitudes of the masses (one mass doubles and the force doubles, the other mass triples and the force triples) and it is inversely proportional to the square of the distance between the masses (move the masses twice as far apart and the force drops to one-quarter, make the separation only 1/3 what it originally was and the force increases nine-fold). OK, so... Now we have a ball on a slight incline... Gravity pulls just the same. In theory, having the ball near a mountain alters the direction of gravity (moving "down" slightly) -- and this is, in fact, reality (we are using this fact to do some pretty awesome measurements) -- but the practical reality is that everything we perceive keys off that fundamental "down is the direction gravity pulls" definition so it doesn't really matter whether the incline is a mountain or a tilted piece of plywood. What does change, though, is the freedom of motion of the ball. The ball is constrained to move along a surface. The pull is "down" but the surface prevents the ball from moving in that direction. The ball tends, instead, to do the next best thing -- it moves in the direction which offers the greatest decrease in gravitational potential. Mathematically, this direction is the "gradient" and you calculate it by differentiating the potential field across the surface. Strictly speaking, the gradient points "uphill" and the negative of the gradient points "downhill." This is the direction the ball starts rolling -- downhill. 1 Share this post Link to post Share on other sites
Brian Posted June 9, 2017 15 minutes ago, MooNiNite said: I find it hard to believe that your explanation is sufficient. But maybe i just need to get out more. You (or the guy who wrote that blog) are correct, BTW -- a carpenter's level will not be much help in identifying a gravitational anomaly. 2 Share this post Link to post Share on other sites
MooNiNite Posted June 9, 2017 Actually my friend wrote it, not me. just fyi. 1 Share this post Link to post Share on other sites
Marblehead Posted June 9, 2017 5 hours ago, Brian said: The apparent "pull" would generally seem be along the line connecting the two centers of mass -- assuming the scenario is such that the approximation is valid. I have actually partially accepted the concept of being "pushed" instead of "pulled". Share this post Link to post Share on other sites
MooNiNite Posted June 10, 2017 (edited) Well aparently Negative Mass was created in a lab. http://minethehive.com/2017/05/tidings-collected-madness-april-2017/ "In general, if you push towards an object, the object moves away from you. With an object of negative mass, if you push towards it, it comes towards you." https://phys.org/news/2017-04-physicists-negative-mass.html Edited June 10, 2017 by MooNiNite 2 Share this post Link to post Share on other sites
