Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 (edited) No it has nothing to do with appearance but basic physics. Take a figure skater, spinning with arms spread out. When she tucks her arms in she spins faster. Same physics. Conservation of angular momentum. http://www.einstein-online.info/spotlights/angular_momentum I know that, but even the Earth has gone from something like a 5 hour day to a 24 hour day over the last 4 billion years. So how much has the Sun slowed down? What I'm saying is that any calculation using today's Sun parameters could be an underestimate of what was happening 4.6 billion years ago. What you believe is irrelevant. Can you prove it? Yeah, that would be because Sun is tidally interacting with planets, notably Jupiter, and loses angular momentum as a result. Well it was already proven by the study on the spin rates of PMS stars. I'll edit the post when I get the link again but I'm sure I've already posted it in the thread. (It wasn't this one but says something similar) http://spacemath.gsfc.nasa.gov/weekly/4Page1.pdf Astronomers can study the rotation of stars in the sky by using an instrument called aspectroscope. What they have discovered is that the speed of a star's rotation depends on its age and its mass. Young stars rotate faster than old stars, and massive stars tend to rotate faster than low-mass stars I don't know why the Sun could have slowed its rotation rate. (Moderators: Another thread maybe? But in some ways it is quite within the scope of this one too. Can we discuss the loss of the Sun's angular momentum in this thread please?) Edited February 20, 2016 by Robittybob1 Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 (edited) I know that, but even the Earth has gone from something like a 5 hour day to a 24 hour day over the last 4 billion years. So how much has the Sun slowed down? What I'm saying is that any calculation using today's Sun parameters could be an underestimate of what was happening 4.6 billion years ago. Moon is ~1/80 of the Earth's mass and is about 63 Earth radii away. Jupiter is ~1/1000 mass of the Sun and is ~1000 solar radii away. As a result the tidal interaction of Sun with Jupiter is thousands of times weaker than in Earth-Moon system. Another thread maybe? Edited February 20, 2016 by pavelcherepan Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 (edited) Does this paper give us the clue https://www.researchgate.net/profile/Keivan_Stassun/publication/249224572_The_Rotation_Period_Distribution_of_PreMain-Sequence_Stars_in_and_around_the_Orion_Nebula/links/53e11aaf0cf24f90ff60df92.pdf New stars are spinning much faster than the Sun. Where does this momentum go? The DDE could be one of many causes of the Sun's momentum loss, photons released in the forward direction on average take away more momentum than the photons coming from the backwards directed ones. That might just be one of many factors. But our work on the DDE in this thread has already been evidenced and can't be ignored. Edited February 20, 2016 by Robittybob1 Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 (edited) New stars are spinning much faster than the Sun. Where does this momentum go? Tell me, what can you make out of this graph that is relevant to your question? https://en.wikipedia.org/wiki/Sun#Main_sequence Edited February 20, 2016 by pavelcherepan Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 (edited) Tell me, what can you make out of this graph that is relevant to your question? https://en.wikipedia.org/wiki/Sun#Main_sequence There is some very interesting things happening at the start of the graph. The first 300 million years has a different slope (all 3 parameters) than the rest of the graphs. It says nothing about angular momentum. Surface temp is about the same in the PMS period as it is now from the 300 million mark. Luminosity is rising from the 300 million mark. (but if the size was larger total luminosity could have been higher at the start.) The radius is increasing from the 300 million mark - that could slow the Sun's rotation rate. (it would depend on mass redistribution.) Edited February 20, 2016 by Robittybob1 Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 (edited) The radius is increasing from the 300 million mark - that could slow the Sun's rotation rate. Yay! (it would depend on mass redistribution.) Nay! https://en.wikipedia.org/wiki/Angular_momentum#Conservation_of_angular_momentum Decrease in the size of an object n times results in increase of its angular velocity by the factor of n2. Since the moment Sun became a main-sequence star it's radius has increased by a factor of 1.11, hence it's rotation should decrease by a factor of ~1.23. That is excluding any tidal effects that will also add to slowing it down. Edited February 20, 2016 by pavelcherepan Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 Yay! Nay! https://en.wikipedia.org/wiki/Angular_momentum#Conservation_of_angular_momentum That little bit is nothing of the magnitude we need to account to the difference between young stars and our Sun. Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 That little bit is nothing of the magnitude we need to account to the difference between young stars and our Sun. 23% reduction in rotation speed is nothing? What is the magnitude you're talking about? POST SOME LINKS! Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 Does this paper give us the clue https://www.researchgate.net/profile/Keivan_Stassun/publication/249224572_The_Rotation_Period_Distribution_of_PreMain-Sequence_Stars_in_and_around_the_Orion_Nebula/links/53e11aaf0cf24f90ff60df92.pdf New stars are spinning much faster than the Sun. Where does this momentum go? The DDE could be one of many causes of the Sun's momentum loss, photons released in the forward direction on average take away more momentum than the photons coming from the backwards directed ones. That might just be one of many factors. But our work on the DDE in this thread has already been evidenced and can't be ignored. What the ???++++++??????? This makes absolutely no sense. Come on seriously ? Do you know the difference between emitter wavelength and observer wavelength? The sun emits the same average wavelength on all facings, we observe different wavelengths due to its angular momentum. It is an observed shift, an adjustment to our measurements. [latex]f=\frac{c+v_r}{c+v_s}f_o[/latex] c is the velocity of waves in the medium; [latex]v_{r}[/latex], is the velocity of the receiver relative to the medium; positive if the receiver is moving towards the source (and negative in the other direction); [latex]v_\text{s}[/latex], is the velocity of the source relative to the medium; positive if the source is moving away from the receiver (and negative in the other direction). Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 What the ???++++++??????? This makes absolutely no sense. Come on seriously ? Do you know the difference between emitter wavelength and observer wavelength? The sun emits the same average wavelength on all facings, we observe different wavelengths due to its angular momentum. It is an observed shift, an adjustment to our measurements. [latex]f=\frac{c+v_r}{c+v_s}f_o[/latex] c is the velocity of waves in the medium; [latex]v_{r}[/latex], is the velocity of the receiver relative to the medium; positive if the receiver is moving towards the source (and negative in the other direction); [latex]v_\text{s}[/latex], is the velocity of the source relative to the medium; positive if the source is moving away from the receiver (and negative in the other direction). Prove to me that the blueshifted photons don't have more momentum than the redshifted ones. It doesn't matter that the average is the same because all the blueshifted ones have a similar angular direction, all are prograde. So where does this extra momentum come from. It seems virtually the same physics as the P-R effect but on a much grander scale. Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 Prove to me that the blueshifted photons don't have more momentum than the redshifted ones. I think it's high time you started proving something and providing supporting argumentation. What is your purpose in this discussion (an all other discussions for that matter)? You don't learn anything, every time you ask same questions as if those haven't been discussed already, you demand and don't give any evidence or calculations and generally act with a total disrespect to the accepted knowledge and search engines. Why don't you stop wasting everyone's time? Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 23% reduction in rotation speed is nothing? What is the magnitude you're talking about? POST SOME LINKS! These results represent an important challenge formodels of rotational evolution during the PMS phase. Based on our period distribution, we suggest that the distribution of initial rotation periods used in models should include PD 0.5È -10 days at an age of 1 Myr. As such, these models must confront the rotational evolution of stars rotating at or near breakup prior to contraction to the main sequence THE ROTATION PERIOD DISTRIBUTION OF PREÈMAIN-SEQUENCE STARS IN AND AROUND THE ORION NEBULA KEIVAN G. STASSUN,1 ROBERT D. MATHIEU,1 TSEVI MAZEH,2 AND FREDERICK J. VRBA3 So they are saying of the stars they looked at they had periods as short as 0.5 day up to 10 days. This must be compared to our Sun with a rotation period of about a month. Because the Solar rotation is variable with latitude, depth and time, any such system is necessarily arbitrary and only makes comparison meaningful over moderate periods of time. Solar rotation is arbitrarily taken to be 27.2753 days for the purpose of Carrington rotations. . Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 The proof in the blooming equation. Yeesh the equation follows conforms to GR. The two terms EMITTER, OBSERVER should be sufficient proof. Change the observer position you get a different result, have the observer move. Does that mean the Sun actually changes temperature because your moving? Measure a static object you are the observer with inertia. Did the temperature of the object change or did your observation of that measurement change? Come on man use a little common sense. Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 I think it's high time you started proving something and providing supporting argumentation. What is your purpose in this discussion (an all other discussions for that matter)? You don't learn anything, every time you ask same questions as if those haven't been discussed already, you demand and don't give any evidence or calculations and generally act with a total disrespect to the accepted knowledge and search engines. Why don't you stop wasting everyone's time? How can you say that? I have provided links all day. Mordred's equation in this post http://www.scienceforums.net/topic/93429-what-dates-are-accepted-for-the-age-of-the-sun/page-6#entry907078 didn'tprove anything so that did not help the discussion. You know how to do LaTex, I don't, so I can't provide formulas sorry. Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 Your own motion can affect redshift measurement. If you fly away from the sun the entire Sun will measure a different wavelength. Does that mean the entire Sun has cooled off? Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 You know how to do LaTex, I don't, so I can't provide formulas sorry. That's the lamest excuse ever. You can't provide links too? Mordred's equation in this post http://www.scienceforums.net/topic/93429-what-dates-are-accepted-for-the-age-of-the-sun/page-6#entry907078 didn'tprove anything so that did not help the discussion. It did. You just didn't make an effort to understand what it means... just like all other times. Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 (edited) The proof in the blooming equation. Yeesh the equation follows conforms to GR. The two terms EMITTER, OBSERVER should be sufficient proof. Change the observer position you get a different result, have the observer move. Does that mean the Sun actually changes temperature because your moving? Measure a static object you are the observer with inertia. Did the temperature of the object change or did your observation of that measurement change? Come on man use a little common sense. I don't know what you are saying exactly sorry. The "observer" in the case I'm claiming does not move. It is the radiation from the sun that changes, in the prograde direction of rotation the radiation is blueshifted and in the other (retrograde) direction it is redshifted. Do you not understand this? This is the principle behind the Differential Doppler Effect. Are you denying that is a valid effect? Are you saying I have misunderstood the DDE? Your own motion can affect redshift measurement. If you fly away from the sun the entire Sun will measure a different wavelength. Does that mean the entire Sun has cooled off? Don't try and confuse the situation please. Edited February 20, 2016 by Robittybob1 Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 (edited) Take a vehicle or any object. Measure its speed via the formula I showed you. It's used in radar guns. Light only travels at c. As the object approaches you the wavelength contracts. As it moves away it's wavelength expands. The same effect occurs whether or not the vehicle is sitting still or if the radar gun is the object moving. This is the same thing with the Sun. The measured wavelength change is a result of its motion relative to your reference frame not the wavelength it is emitting. Edited February 20, 2016 by Mordred Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 That's the lamest excuse ever. You can't provide links too? It did. You just didn't make an effort to understand what it means... just like all other times. He doesn't need to talk about observers moving because there are no observers as such, for the radiation from the sun shines throughout the solar system , galaxy or universe. It just radiates out into space. Link to comment Share on other sites More sharing options...
pavelcherepan Posted February 20, 2016 Share Posted February 20, 2016 Man, I wish I haven't used the "double-facepalm" card so soon. Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 Read my last post. With all the time Youve Bern on this forum. One would have thought you would have learned how Doppler effect or gravitational and Cosmological redshift works. Man, I wish I haven't used the "double-facepalm" card so soon. Me too Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 Take a vehicle or any object. Measure its speed via the formula I showed you. It's used in radar guns. Light only travels at c. As the object approaches you the wavelength contracts. As it moves away it's wavelength expands. The same effect occurs whether or not the vehicle is sitting still or if the radar gun is the object moving. This is the same thing with the Sun. The measured wavelength change is a result of its motion relative to your reference frame not the wavelength it is emitting. I think you are wrong. It might be "emitting" that wavelength but it takes more momentum away from the Sun for the frequency is increased and a photon's momentum is directly proportional to it frequency. p = E c = h ν /λ ν = h λ Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 (edited) Roflmao... Our own motion relative to the CMB causes a dipole anisotropy to the CMB temperature measurements. Does that mean the universe is hotter in the direction of our motion? Man spend a little time studying and less jumping to misguided conclusions. Thats like saying I can burn you up by measuring the frequency your emitting and flying fast enough toward you while I measure your temperature. Edited February 20, 2016 by Mordred Link to comment Share on other sites More sharing options...
Robittybob1 Posted February 20, 2016 Author Share Posted February 20, 2016 (edited) Roflmao... Our own motion relative to the CMB causes a dipole anisotropy to the CMB temperature measurements. Does that mean the universe is hotter in the direction of our motion? You are now asking questions about things I have no knowledge of. [Mordred - are you a moderator?] Edited February 20, 2016 by Robittybob1 Link to comment Share on other sites More sharing options...
Mordred Posted February 20, 2016 Share Posted February 20, 2016 (edited) Because your not listening. Instead your assuming I'm wrong simply because you don't understand it. No I'm a resident expert, that grants me certain moderator leeway. Edited February 20, 2016 by Mordred Link to comment Share on other sites More sharing options...
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