I am not a student and have little to no knowledge of this subject .still after reading some on dark matter I was compelled to to fitnd someone who'd know the answer to my question about that 20% . So my question is this . In caculating earth's mass . When determining the 20% discrepancy that we believe to be dark matter . Was human and an animal mass also included ? However if my last question was with out any sense since the missing 20% (dark matter) Is within the solar system and not in the mass of earth alone. Still earth's mass I would believe must contain the living mass as well . This missing 20% may pertain to the mass of unknown living mass throughout out the solar system . Supporting to what of angels and demons also called aliens , spirits , god's , etc. I do hope that my questions are not completely idiotic . I just felt that for some reason this was something that was not considered when determining mass of earth since living mass is always changing due to population . How ever when u consider all life come from the father and he always was and always will be . Then his mass would be likewise . In that in which he breathed into the living . True ?
is the earth spinng because the sun is a negative charge resting on the circumference of the earth and that space is a positive energy source also pushing on the other pole ? much like a metal ball being suspended and stabilized with positive negative charges? if so then would or could the earth be spinning much like a top does in a circular motion as if it will always spin in the same spin motion of earth because it to is affected by the magnetic pushes and pulls....right? could we measure whether the earth is spinning at the same rate of speed as it was 10,15, 25, or even 50 years ago? if it is slowing does that mean that if earth loses momentum this will cause the Spheres to be slowly deteriorated mime-ing global warming ? could we feasibly measure the rate at which earth would stop rotating if at all? does it mimmick the pi equation at all? I am sorry I have only a couple of years of college and I have been bothered buy these questions ....I am fifty years old and an introvert I look forward to your answer
These are my calculations applied as I was taught in Physics first year university:
A 50g marble is attached to a 1m string wrapping itself around your finger held above your head at a rate of one revolution every second until it reaches 5cm from your finger. Let s do the math:
mass m = 0.05 kg
radius r = 1 m
angular velocity w = 6.28 r/s
velocity v = w/r = 6.28/1 = 6.28 m/s
momentum p = mv = 0.05*6.28 = 0.314 kg.m/s
angular momentum L = rp = 1*0.314 = 0.314 kg.m^2/s
r = 0.05 m
L =0.314 kg.m^2/s (using conservation of angular momentum)
v = L/rm= 0.314/0.05 = 125.6 m/s
If we calculate the centrifugal force generated by the final scenario:
F = mv^2/r = 0.05*125.6*125.6/.05 = 15775.36 N
Which is about the equivalent of the force of gravity on 1600 kg This is a classic example given as proof of conservation of angular momentum in first year university physics lectures. It is the same principle applied to the other example when an ice skaters arms are pulled in when in fact angular momentum is also not conserved. You have a choice - conserve angular momentum or conserve linear momentum. Linear momentum wins - always. Conservation of angular momentum is an fact a fallacy. Even you yourself have answered a question regarding a spinning skater using conservation of angular momentum - you answer to that question is false. Your suggestion regarding torque also applies in that example. There is no such thing as conservation of angular momentum unless nothing changes and if nothing changes then there is nothing interesting happening and the law cannot be applied. As the radius reduces, so does the angular momentum linearly whilst the angular velocity increases linearly. Why is that so difficult to accept ? If I am wrong, then please give me an example where conservation of angular momentum can actually be applied ?
ME: Did you even bother to read my answer? Angular momentum is not conserved in this situation and so your calculation is meaningless.
QUESTIONER: I did read your answer, and your answer is bs. There is no torque being applied to the marble by the string because the force is perpendicular to the motion. You are correct in that conservation of angular momentum is not conserved in this situation because conservation of angular momentum is not conserved in any situation. Clearly you have not bothered to read my email. I am tired of trying to explain this to people who consider themselves physicists because their heads are buried so deep in Newtons ass that they cannot see reality anymore. He was just a human and he made a mistake.
ME: At this point I usually give up trying to reason. For the benefit of whoever is reading this question (and unlike the questioner, willing to think) here is a brief explanation of torque and angular momentum. He is right that there is no torque about an axis passing through the point where the string is unwinding from his finger; but it is meaningless to calculate the angular momentum about this axis because that point moves around the circle and is therefore not an inertial frame. But the axis passing through the center of his finger is in an inertial frame (at rest) and there is a torque about that axis because T has a component perpendicular to r. and therefore τ=rxT≠0. I should also add that linear momentum does not "win" in this situation; because there is a force on the marble (T) linear momentum is not conserved and any fool can see that because it is a vector and constantly changing its direction. Oh, never mind, I am just a physicist with my head "buried deep in Newton's ass".
QUESTIONER: You are truly a closed minded idiot. Soon to be proven so. The world of physics has been deluded for centuries and you stand here in the face of clear evidence exposing it and point your finger at the messenger saying whatever comes to mind to protect your delusion. Good luck with that. As far as your little wall of fame is concerned, the road to give a f#$* is the other direction.
QUESTIONER: I apologise for my behaviour. You are doing great things for physics education in general with your fantastic web site. I was also impressed with your quick response. I believe that I have found a huge flaw in physics which has ramifications ranging from astronomy to quantum mechanics in which they are applying the law of conservation of angular momentum and it is incorrect. I am extremely frustrated because it seems impossible to get this through to anyone. I do not agree with your answer because my question is a classic example used in physics classes to demonstrate conservation of angular momentum. I still maintain that your previous answer to another question posed by somebody on your web site regarding the skater pulling in her arms is false. But you do not deserve to be insulted and I would like to take back the insulting things I have said. Please accept my apology.
ME: Thank you for your remarks; we all get a little hot-headed sometimes, particularly when we are passionate about something. I would ask you to think more carefully about the particular problem we have been arguing about. I assure you that you will not find the "tetherball problem" cited in any reputable text as an angular momentum conservation example; if it appears at all it will be as an example of just the opposite. If you had an instructor who presented it as such, he/she was incompetent. I will tell you an amusing anecdote from my own teaching career. I once had to miss a couple of classes I was teaching because of a research trip and had a graduate student teach my classes and administer an exam I had written. He taught the class that angular momentum was conserved in the tetherball problem; subsequently, nearly every student in the class missed that problem on the test. I had to readjust my grades for that test by taking that problem out. Finally, I should tell you the "classic" angular momentum conservation example you are probably remembering from your student days. It is very like the problem we have been arguing about with one small difference: instead of the string getting shorter as it wraps around a cylinder, it gets shorter by pulling it through a small hole. In this case, there is truly no torque on the mass because the tension is directed toward the axis which passes through the hole. So, in this case mv1r1= mv2r2. Since the velocity increases as you pull it in, energy is not conserved. So, v2=v1(r1/r2)=125.6 m/s as you calculated for the other case. Any real string would break before getting in to 5 cm. (I see that I used 5 g instead of your 50 g in my earlier calculation, but the mass does not matter in the velocity calculation. I have corrected that.) Finally, I appeal to the overwhelming evidence from experiments and observations. Kepler’s second law would not be true if angular momentum is a “fallacy”; but think of all the observations which have verified this law. Angular momentum is absolutely crucial in all quantum mechanical calculations of atomic and nuclear properties; in a century of quantum physics, calculations have never failed to correctly describe nature.
QUESTIONER: Your assertion that moving the centre of the radius of the turn slightly to one side because it is wrapping around a finger will impart a force any other direction than perpendicular to the movement of the marble is simply false. At any instantaneous moment, the tension on the string will be imparting a force perpendicular to the motion of the marble and the diameter of the finger will be of no consequence. No torque will be applied to the system. Pulling the string through a small hole will not produce the result that you are advocating. In fact, I have proven this not to be the case with a very simple marble drop apparatus which has two channels, one which has the marble go through a fixed radius 90 degree bend and the other which goes through a reducing radius 90 degree bend. I assure you that the velocity is not affected. If the velocity were to increase then the linear momentum would not be conserved. If Keppler’s second law is based upon angular momentum, then I can assure you that it is also false. Any calculation which applies the conservation of angular momentum cannot possibly correctly describe nature. Just because everyone thinks it is so does not make it so. This is the type of thinking that lead to this fallacy being undiscovered for centuries. Mark my words, because a lot of people are going to be eating theirs. The reality of the tethered object scenario is that the angular momentum decreases along with the radius. The angular velocity increases simply because the object has a shorter path to traverse and therefore does it faster. 300 years of science is simply wrong. The overwhelming evidence that you appeal to is all false. I am sure that some inexplicable paradoxes have arisen within quantum mechanics because their calculations are based on an invalid law. These can now be explained. Science is about reality. It’s time to wake up and smell the coffee. The truth is that once you realise and accept what I am saying, you will no longer understand how you believed otherwise because it is so obvious. Which of course makes it more difficult to explain to someone who is still suffering under the delusion. Respectfully, it is you sir who needs to think more carefully.
ME: At this point, it is fruitless to carry on! No point in arguing with someone who cannot even calculate torque.
QUESTIONER: Your suggestion that there is a torque on the marble as it unwinds from the finger is on two counts incorrect. Firstly, the marble is winding up on my finger and therefore the torque which you assert is applied would further increase the angular momentum. Secondly there is no torque. If you would care to think about it a little, you would realise this. Also if your were to actually try a little experiment - which I have tried - you would find that there is little difference from the marble wrapping up on your finger or being pulled through a small hole. I assure you that there is no snapping of the string, or anywhere near the kind of force which conservation of angular momentum predicts. I have discovered something which changes everything about science and the world does not care to listen. It will soon be realised though because the truth has eventually to come out. Conservation of angular momentum is false. The fact that you choose to ridicule the person that points it out to you does not change the fact.
ME: (I am such a fool to continue debating this guy who keeps sending me nonsense messages, but the teacher in me just cannot resist.)
The notion that because the force is perpendicular to the velocity says nothing whatever about the torque which the force exerts. You are right, the tension T is perpendicular to the velocity v, but this says (as I said before that T does no work and so v remains constant (energy conserved). (Note that the speed v, not the velocity v, remains constant so linear momentum is not conserved; that is to be expected since the criterion for linear momentum to be conserved is that there be no external force and T is a force on the marble.) Now the most important thing is to discuss angular momentum, since you insist that angular momentum is "a fallacy". Newton's first law for rotational motion is that the angular momentum of a system remains constant if there are no external torques on the system. Since there is only one force here, we have to determine if T exerts a torque on the marble. In order to calculate angular momentum or torque, you must specify an axis about which to calculate these quantities. Now you seem to want to choose point A in my figure as that axis, and, indeed, the torque about that point at this instant is zero. But that point is not where it was a second ago and is not where it will be a second from now; that point is moving around in a circle. But, that would mean that the point A is in a noninertial frame of reference (accelerating) and any beginning student in physics knows that Newton's laws of motion work only in an inertial frame. So you must choose some other axis if you want to determine whether angular momentum is conserved as predicted. You can choose any axis which is fixed in space, but far-and-away the simplest calculation results from choosing the center of your finger (point C) as the axis about which to calculate. So, in order for T to exert a torque about C you need to determine if it has a component perpendicular to the moment arm r; as my figure clearly shows, there is such a component labeled as Tt, the component of T tangential to the radius r. The net torque is therefore Ttr. There is a torque and therefore angular momentum is not conserved. Note that the direction of the torque is such that the angular momentum will decrease as the string wraps around your finger.
QUESTIONER: I met a fellow I want say his name. He told me he was almost certain that the earth formed itself via two black dwarf stars. He said they were still there. I ask how and he began to speak about how gases from those stars were produced at that age of those two stars and he said they didnt have enough energy to burn the gases so some turned to water. He said the sun wasn't shining at that time and those two stars inside our planet is where gravity comes from. He kept speaking about another force which he called ANTAVITY. He said antavity was the reason the suns gravity didnt pull all planets via gravity into itself. As he spoke I ask about what did he think caused mars to go out of its ecliptic as it lined up with earth and he said all planets dont have the same type stars because of there atomic makeup. My question is "is that possible ?
ME: Why would you ever think such nonsense could have any truth to it? Don't even waste time thinking about it.
QUESTIONER: Dear Mr Physicist , Due to a better answer from the science community concerning earths gravity and its origins I have no choice but to believe this gentleman's answers. Hydrogen and oxygen make water . Its very possible those dark stars do supply earth with gravity and in their origins its very possible that is the origin of earths water. I have learned one thing and that is science does not have all the answers and sometimes when a answer is needed they make one up. Gravitational waves are now detectable is that myth or TRUTH where is the proof.
ME: Ha, ha, that’s a good one! You’re that “fellow”, aren’t you? Hydrogen is the most abundant element in the universe and oxygen is produced in massive quantities in dying stars. Hydrogen burns very easily. No mystery where water comes from. “Supply earth with gravity”? What does that even mean? Gravity is not something you can carry in a cup.
QUESTIONER: Intellectual humility isn't very popular in the physicist neighborhoods. I am certain of this. America and special interest groups support it like it were truth. Hahaha. Other then the above thank you for you time..
QUESTIONER: Oh and ah P.S. that same man is telling me to pay careful attention to our sun. He says its about to take its last and final breath. I told him I have read about the red giant. He said the sun would turn multiple folds brighter before it ever turns to a red GIANT. I guess you will see if I am that same man because a human would have no way of knowing this because we look to you fellows to inform us. He also speaks of planet displacement due to ANTAVITY. Later dude I had to P.S. YOU