What dates are accepted for the age of the Sun?

[Robittybob1]

You can for the purpose of learning choose rounded off values. At the moment were more interested in the steps themselves.

 

Very good, remember to learn latex you can quote a post with a formula so do that on my post (it will help learn the rules and syntax)

 

Here is some useful relations.

 

[latex]\frac{\Delta_f}{f} = \frac{\lambda}{\lambda_o} = \frac{v}{c}=\frac{E_o}{E}=\frac{hc}{\lambda_o} \frac{\lambda}{hc}[/latex]

I need things in words to really understand them. So the ratio of the wavelength is the inverse of the ratio of the frequencies and this is the same as the ratio of velocity difference and ratios of energy and momentum. Something like that. First step is to convert wavelengths to frequencies.

Has 500 nm light got a frequency of 6E+14 Hz?

Edited February 22, 2016 by Robittybob1

[Mordred]

[latex]f=\frac{c}{\lambda}[/latex]

 

[latex]e=\frac{ch}{\lambda}[/latex]

Edited February 22, 2016 by Mordred

[Robittybob1]

Instantaneous tangential velocity = distance /time

2*pi()*r/T = 2.00E+03 or more precisely 1.9951E+03 meters/sec on the surface of the Sun so the difference in velocities will be twice that 3.9903E+03 m/sec.

[latex]f=\frac{c}{v}[/latex]

I'm working on that. See my prior post thanks

 

"Has 500 nm light got a frequency of 6E+14 Hz?"

We have the original frequency and now a difference in speeds.

Edited February 22, 2016 by Robittybob1

[Mordred]

[latex]5.9958*10^{14}[/latex] Hz

 

Close enough lol.

 

My fault on that formula typed the wrong relation halfway through lol I fixed it.

[latex]v=\frac{c}{\lambda}[/latex]

Ok now you know the relations.

 

After you calculate the DDE for a static observer, (handy for a reference). If the observer is moving toward or away from you will need to do vector addition. To calc the new redshift/blueshift.

 

Now this far it's easy. What if the object is moving left or right?

 

For that step we need a difference formula. I want you to look at transverse Doppler effect this entire page is important to understand.

 

https://en.m.wikipedia.org/wiki/Relativistic_Doppler_effect

 

 

Next work out the orbit of a dust particle, (remember it will probably be moving in the directory of the Suns rotation)

 

Also probably elliptical.

 

You now have the tools to model build DDE on dust. Keep in mind at a certain radius from the Sun DDE won't matter as it will get the energy from both sides of the Sun.

 

 

Hope that helps, play around with the relations, practice conversions, then build you new skills into the full metric

The blackbody temperature and these conversions will help gather data from datasets you may have but just had the wrong data type for your skill upon first reading. This will open up a larger volume of useful data.

Edited February 22, 2016 by Mordred

[Robittybob1]

[latex]5.9958*10^{14}[/latex] Hz

 

Close enough lol.

 

My fault on that formula typed the wrong relation halfway through lol I fixed it.

[latex]v=\frac{c}{\lambda}[/latex]

Ok now you know the relations.

 

After you calculate the DDE for a static observer, (handy for a reference). If the observer is moving toward or away from you will need to do vector addition. To calc the new redshift/blueshift.

 

Now this far it's easy. What if the object is moving left or right?

 

For that step we need a difference formula. I want you to look at transverse Doppler effect this entire page is important to understand.

 

https://en.m.wikipedia.org/wiki/Relativistic_Doppler_effect

I think we have to assume that on average the dust particles are orbiting the Sun so they don't consider small movements, this way that way, for they are averaged out. So the dust will be moving as well as the Sun surface and that will be at a much higher rate than Sun surface but out at the distance to the planets at least all the radiation is coming basically from underneath, only scattered light will be hitting particles in the for or against direction of travel. So basically the momentum will provide lift (outward direction flow of dust maybe???)

 

In those papers they look at one dust particle hit simultaneously from a high momentum and a low momentum photon and see which way it is pushed and or dragged.

 

I spoke to a physics graduate (PhD) who was rather intrigued with the idea that the Sun angular momentum could be reduced by the DDE. I think it might be better just to have a look at the effect on the Sun's rotation first and worry about the dust later. But it doesn't take much imagination to see if the radiation is slowing the Sun it is transferring that momentum to the dust particles and they are being accelerated to a higher orbit. Pressure waves and planets then become possibilities from the pressure from the inside pushing against the falling matter shielded from the radiation by the dust itself. Bands as is commonly seen is what you would then expect and in the core of these planetesimals are being formed. So was it during the the T Tauri phase of the Sun developement that the planets accreted from the inside bands to the next band for the pressure on the inner surface of the dust disk is always the greatest?

I would be surprised if relativistic Doppler effect has any part to play.

Edited February 22, 2016 by Robittybob1

[Mordred]

Assuming an average movement of the dust is about the best you can do realistically. For example now that your more aware of the calculations involved. Ask yourself

 

"How much difference can 0.00395 nm wavelength have on a dust particles movement"

 

One joules/m^3 is equal to 6.24×10^18 eV

 

One joule is equal to one Newton.

 

so assuming 100% transfer to a 1 metre cubed body (unrealistic)

 

0.00395 nm corresponds to 3.1388*10^5 eV not even a Newton.

 

a dust particle wouldn't get a full m^3 of that energy. It would only recieve a miniscule fraction from DDE. That's assuming 100% absorbtion.

 

amazing what happens when you crunch the numbers.

 

Poynting Robertson metric uses mie scattering, and luminosity. The above was the DDE effect itself.

 

Even if we run through the calcs for Poynting Roberston. I think you will find the primary contribution to how planets develop will be more due to what's involved in density waves via Nebulae theory.

 

DDE and Poynting vector would be minor players to the hydrodynamic influence. They may have influence but it's small comparatively.

 

For your modelling, now that you have a better understanding I think you'll agree that a focus on understanding the influence of density waves may be your most applicable step towards your model.

 

This is one of the reasons the astronomy textbooks cover density waves when explaining nebulae theory in particular when covering planetary formation.

(The handy part of density wave hydrodynamics is that it's a multiparticle metric) it treats the dust in the same manner as an ideal gas. So the techniques and formulas used there will be extremely handy to model your multi particle system.

 

I'm positive you'll agree it would be nearly impossible to model a nebulae particle by particle. So you will need the hydrodynamic metrics.

Edited February 22, 2016 by Mordred

[Robittybob1]

Assuming an average movement of the dust is about the best you can do realistically. For example now that your more aware of the calculations involved. Ask yourself

 

"How much difference can 0.00395 nm wavelength have on a dust particles movement"

 

One joules/m^3 is equal to 6.24×10^18 eV

 

One joule is equal to one Newton.

 

so assuming 100% transfer to a 1 metre cubed body (unrealistic)

 

0.00395 nm corresponds to 3.1388*10^5 eV not even a Newton.

 

a dust particle wouldn't get a full m^3 of that energy. It would only recieve a miniscule fraction from DDE. That's assuming 100% absorbtion.

 

amazing what happens when you crunch the numbers.

 

Poynting Robertson metric uses mie scattering, and luminosity. The above was the DDE effect itself.

 

Even if we run through the calcs for Poynting Roberston. I think you will find the primary contribution to how planets develop will be more due to what's involved in density waves via Nebulae theory.

 

DDE and Poynting vector would be minor players to the hydrodynamic influence. They may have influence but it's small comparatively.

 

For your modelling, now that you have a better understanding I think you'll agree that a focus on understanding the influence of density waves may be your most applicable step towards your model.

 

This is one of the reasons the astronomy textbooks cover density waves when explaining nebulae theory in particular when covering planetary formation.

(The handy part of density wave hydrodynamics is that it's a multiparticle metric) it treats the dust in the same manner as an ideal gas. So the techniques and formulas used there will be extremely handy to model your multi particle system.

 

I'm positive you'll agree it would be nearly impossible to model a nebulae particle by particle. So you will need the hydrodynamic metrics.

I was hoping we would go through all those calculations together so there did not need to be thoughts as to whether you've done your calculations wrongly. These sort of problems are not easy so can you be certain that you have done it correctly? Even when I read your post I wonder what it means and I wish we were taking it slowly.

I have never seen the type of calculations you seem to be using.

What does "One joule is equal to one Newton." mean? Google definition of Joule:

 

The joule (/ˈdʒuːl/), symbol J, is a derived unit of energy in the International System of Units. It is equal to the energy transferred (or work done) to an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or N. m).

"One joule is equal to one Newton.meter" Over a long period of time who knows how much of that energy could be transferred, and there are meters and meters of dust between the Sun all the way out to Mars (more than 200 billion meters) or even further if needed. www.universetoday.com/14828/orbit-of-mars/

 

At perihelion Mars is 206,655,215 km from the Sun and at aphelion it is 249,232,432 km distant. That is a variation of of just under 42,600,000 km. The average distance from Mars to the Sun (called the semi-major axis) is 228 million km. It takes Mars approximately 687 Earth days to complete on orbit.

If the dust gets that dense that light doesn't get through that virtually implies that other than what is scattered the rest is 100% absorbed hence the momentum is transferred. Even the scattering transfers some momentum (radiation pressure).

 

In fact the photons don't even need to be absorbed to have taken momentum away from the Sun, the momentum is in the photons whether or not they are absorbed. These photons could still be traveling across the Universe.

 

You are also looking at the parameters (size and speed) of the current Sun yet I found references that indicate PMS stars are much larger and spin many times faster, both effects that will intensify the DDE.

Please consider coming back and working together so we both remain in agreement step by step.

Edited February 22, 2016 by Robittybob1

[Mordred]

I have no problem with that, nor did I state there isn't an influence. We showed that there is. However our goal is to model a nebulae. One isn't going to do that particle by particle.

 

My suggestion is to start looking into metrics that will teach you how to model multiparticle systems.

 

Then we can incorporate Poynting vector and possibly DDE into those metrics.

 

That's the little trick with modelling. A model may or may not be correct and most can be improved.

The techniques of those models can be used in adapting to a new model.

 

 

We can continue doing the single particle influences now if you choose or later. Doesn't matter to me. I'm just here to help. Eventually though you Will need to learn hydrodynamics to accomplish what your after.

http://blogs.hsc.edu/sciencejournal/files/2014/03/Chaudhry.pdf

 

http://arxiv.org/abs/1008.2973

 

A particular direction is accretion theory.

[pavelcherepan]

 

 

If the dust gets that dense that light doesn't get through that virtually implies that other than what is scattered the rest is 100% absorbed hence the momentum is transferred.

 

Citation needed or just stop making stuff up.

[Robittybob1]

I have no problem with that, nor did I state there isn't an influence. We showed that there is. However our goal is to model a nebulae. One isn't going to do that particle by particle.

 

My suggestion is to start looking into metrics that will teach you how to model multiparticle systems.

 

Then we can incorporate Poynting vector and possibly DDE into those metrics.

 

That's the little trick with modelling. A model may or may not be correct and most can be improved.

The techniques of those models can be used in adapting to a new model.

 

 

We can continue doing the single particle influences now if you choose or later. Doesn't matter to me. I'm just here to help. Eventually though you Will need to learn hydrodynamics to accomplish what your after.

Thanks if you understand it you might be able to teach me a bit and we will advance the idea in doing so. I never thought we were attempting to model a nebula! What made you think that far ahead in a thread on formation of the Sun?

 

Citation needed or just stop making stuff up.

I am sure that is standard physics the dust would act like a black body. All the photons entering a black body absorber will be held within it. I have no doubt there are plenty of dust disks that are opaque. Surely you know this without citations but if you insist I'll see if I can find it. Do you really think it is possible to shine light along the ecliptic through the mass of the dust disk?

 

Googling "Black body" and "dust disk" gives many results http://www.aanda.org/articles/aa/abs/2008/30/aa8881-07/aa8881-07.html

 

 

T Beckert, T Driebe, SF Hönig, G Weigelt - Astronomy & Astrophysics, 2008 - aanda.org

... silicate feature around m. We find that the mid-IR emission from the nucleus can be reproduced

by an extended dust disk or torus ... range with and small temperature variations along the line of

sight through the dusty torus, the emission spectrum approaches a black body and the ...

Edited February 22, 2016 by Robittybob1

[pavelcherepan]

 

 

dust gets that dense that light doesn't get through

 

Stop dodging questions. Please get a relevant citation that shows that dust density in protostellar cloud can be so high as to block the light completely rather than being something like 10^{-a lot} particles/m³.

[Robittybob1]

 

Stop dodging questions. Please get a relevant citation that shows that dust density in protostellar cloud can be so high as to block the light completely rather than being something like 10^{-a lot} particles/m³.

There is radiation coming out from the dust disks but only what is expected from a black body. I have edited my previous post with a citation. (From the Google search page only but the words are there.)

Edited February 22, 2016 by Robittybob1

[Mordred]

Thanks if you understand it you might be able to teach me a bit and we will advance the idea in doing so. I never thought we were attempting to model a nebula! What made you think that far ahead in a thread on formation of the Sun?

 

You need to model a nebula in order to form a star/Sun.

 

A) nebula density

B) average density

C) material type ie hydrogen, lithium deuterium etc.

D) average blackbody temperature of nebula

E) condensed anisotropy development

F) Jeans equations (hydrodynamic)

G) along with f cause of collapse

H) isothermal sphere distribution of mass to protoplanetary disk. (Hydrodynamics)

 

However right now you need to know the basic physics. We covered blackbody to redshift. We haven't gotten into shell theorem, Keplers laws in particular elliptical orbits

 

Then we need hydrodynamic approximations (which involves mass/energy to temperature/pressure relations).

 

star formation involves a lot of relations and knowledge.

[Robittybob1]

You need to model a nebula in order to form a star/Sun.

 

A) nebula density

B) average density

C) material type ie hydrogen, lithium deuterium etc.

D) average blackbody temperature of nebula

E) condensed anisotropy development

F) Jeans equations (hydrodynamic)

G) along with f cause of collapse

H) isothermal sphere distribution of mass to protoplanetary disk. (Hydrodynamics)

 

However right now you need to know the basic physics. We covered blackbody to redshift. We haven't gotten into shell theorem, Keplers laws in particular elliptical orbits

 

Then we need hydrodynamic approximations (which involves mass/energy to temperature/pressure relations).

 

star formation involves a lot of relations and knowledge.

But haven't these already been worked on? I don't have many doubts about the current theories on that topic. So I don't know what the benefit we would get by going back over it unless you can see some major flaws in the current accepted theory.

Are you not happy with the current ideas on nebulae?

Edited February 22, 2016 by Robittybob1

[Mordred]

"Nebulae are often star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas, dust, and other materials "clump" together to form larger masses, which attract further matter, and eventually will become massive enough to form stars. "

 

https://en.m.wikipedia.org/wiki/Nebula

 

Now ask yourself what caused a nebulae to collapse".? They can be balanced in distribution so never collapse.

 

Leading theory with evidence support of iron 60 I believe it was (which can only be formed in super nova events) is a nearby super nova is the cause

[pavelcherepan]

 

 

There is radiation coming out from the dust disks but only what is expected from a black body. I have edited my previous post with a citation. (From the Google search page only but the words are there.)

 

That's not it. This is from outside perspective.

 

Look at this simple back-of-the-hand calculation. Say we have a protostellar cloud ~200 AU in radius and we're looking at it from outside. 200 AU is ~3*10¹³ m. Hence non-transparency of protostellar clouds when viewed from outside only implies that that particle/dust density is somewhere above 10^-13 particles/m³. That way most of photons travelling 200 AU is highly likely to hit a particle a get scattered or absorbed.

 

In reality specifically dust density as modelled for proto-solar system is around 10^-8-10^-15 particles/m³ so it's mostly empty space (I'll add paper reference once I get home).

 

With that kind of thinking you probably also believe that a scene form Star Wars where Han Solo showed "incredible skill" navigating through asteroid belt is realistic.

 

 

 

star formation involves a lot of relations and knowledge.

 

True dat. Robbity, I suggest you have a look at this paper for example and understand the depth of knowledge required to model dust transportation in protosolar cloud. I'm totally lost in all these giant formulas, but who knows, they might make sense to you.

 

http://adsabs.harvard.edu/full/1984ApJ...287..371M

Edited February 22, 2016 by pavelcherepan

[Mordred]

But haven't these already been worked on? I don't have many doubts about the current theories on that topic. So I don't know what the benefit we would get by going back over it unless you can see some major flaws in the current accepted theory.

Then explain what your trying to accomplish. You kept pushing DDE, Poynting vectors etc throughout this thread.

 

What does that have to do with how the Sun formed?

[Robittybob1]

 

That's not it. This is from outside perspective.

 

Look at this simple back-of-the-hand calculation. Say we have a protostellar cloud ~200 AU in diameter and we're looking at it from outside. 200 AU is ~3*10¹³ m. Hence non-transparency of protostellar clouds when viewed from outside only implies that that particle/dust density is somewhere above 10^-13 particles/m³. That way a photon travelling 200 AU is highly likely to hit a particle a get scattered or absorbed.

 

In reality specifically dust density as modelled for proto-solar system is around 10^-8-10^-15 particles/m³ so it's mostly empty space (I'll add paper reference once I get home).

....

I'd like to see that reference. It is completely different to my understanding.

Then explain what your trying to accomplish. You kept pushing DDE, Poynting vectors etc throughout this thread.

 

What does that have to do with how the Sun formed?

Timing planetesimal and planet formation and the timing of the clearing of the dust disk from the inner parts of the Solar System. What was the role of the Sun in doing this.

Also defining the extent of the habitable zone.

 

If we get time maybe we should look at your ideas on nebula collapse.

Edited February 22, 2016 by Robittybob1

[pavelcherepan]

 

I'd like to see that reference. It is completely different to my understanding.

 

I've already included the reference, but I'll repost for your convenience. Or if this one is too complicated, go on Google Scholar and search by keywords "dust & protosolar cloud" and ye shall find.

 

http://adsabs.harvard.edu/full/1984ApJ...287..371M

 

 

 

Also defining the extent of the habitable zone.

 

That's nonsensical.

Edited February 22, 2016 by pavelcherepan

[Robittybob1]

 

I've already included the reference, but I'll repost for your convenience. Or if this one is too complicated, go on Google Scholar and search by keywords "dust & protosolar cloud" and ye shall find.

 

http://adsabs.harvard.edu/full/1984ApJ...287..371M

 

 

That's nonsensical.

1983 that's fairly old, there must be something more recent. I'll think you'll find many ideas held pre-1983 have been superseded.

Why is redefining the habitable zone nonsensical? I have already discussed the habitable zone and the study did not include Mercury but did include Venus. There was no study on dust clearing of the inner solar system.

Edited February 22, 2016 by Robittybob1

[pavelcherepan]

You don't seem to read stuff at all. I'm not planning to spoon feed you. You know, "Give Robittybob a fish link and you'll make him happy for one day, teach him how to use search engines and he'll be happy forever".

 

 

 

Or if this one is too complicated, go on Google Scholar and search by keywords "dust & protosolar cloud" and ye shall find.

 

What do you mean by that (below)? There's been plenty of studies, just like the one I quoted.

 

 

 

There was no study on dust clearing of the inner solar system.

Edited February 22, 2016 by pavelcherepan

[Robittybob1]

You don't seem to read stuff at all. I'm not planning to spoon feed you. You know, "Give Robittybob a fish link and you'll make him happy for one day, teach him how to use search engines and he'll be happy forever".

 

 

What do you mean by that (below)? There's been plenty of studies, just like the one I quoted.

 

That was particular to the study I had previously linked on this thread, not that it has never been studied. That link you sent me was about 20 pages long and just reading the abstract reads like an outdated concept. Sorry I haven't got the time just now to read it. Is it like the basis of your knowledge do you accept what is said? If you do maybe I'll force myself to read it just to see where you are coming from.

Edited February 22, 2016 by Robittybob1

[pavelcherepan]

 

 

That was particular to the study I had previously linked on this thread, not that it has never been studied. That link you sent me was about 20 pages long and just reading the abstract reads like an outdated concept. Sorry I haven't got the time just now to read it. Is it like the basis of your knowledge do you accept what is said? If you do maybe I'll force myself to read it just to see where you are coming from.

 

As always your scientific discussion manners are impeccable (sarcasm intended).

 

This is not the basis of my knowledge. The basis of my knowledge is my Uni education and further reading of multiple papers and books on the topic.

 

The link I gave you shows how complex modelling of dust migration is and should probably give you an idea that you attempting to come up with the solution of your own is very unlikely given your rudimentary understanding of processes involved (not that I'm claiming to have perfect understanding either). As you've been told before, you should try and tackle small problems one at a time. Once you have a good understanding of those you can try and move on to bigger questions.

 

It won't help if you continuously start meaningless discussions and then don't learn anything from them, and then will the same poor understanding in the next discussion.

 

EDIT: Another back of the hand calculation. All the mass in solar system other than Sun itself is about 1/600th of Sun's mass or 2*10³⁰/600 = 3*10²⁷ kg approximately. Now we assume this mass is all in dust particles with density ~2 g/cm³. And also to not bother with distribution through SS we'll jam all these particles within 1 AU from the Sun and 0.5 AU above and below ecliptic. We'll take particles to be ~1mm in size on average.

 

4/3*pi*(0.001)³*2000 = 8*10^-6 kg per particle, hence 3*10²⁷/8*10^-6 = 4*10³² particles approximately.

 

Total volume pi*r²*h = 1*10³⁴ m³

 

And then particle density would be ~10^-2 particles/m³. One particle per 100 cubic meters!

 

So even in this absolutely unrealistic scenario your idea doesn't stand to scrutiny.

Edited February 22, 2016 by pavelcherepan

[Robittybob1]

 

As always your scientific discussion manners are impeccable (sarcasm intended).

 

This is not the basis of my knowledge. The basis of my knowledge is my Uni education and further reading of multiple papers and books on the topic.

 

The link I gave you shows how complex modelling of dust migration is and should probably give you an idea that you attempting to come up with the solution of your own is very unlikely given your rudimentary understanding of processes involved (not that I'm claiming to have perfect understanding either). As you've been told before, you should try and tackle small problems one at a time. Once you have a good understanding of those you can try and move on to bigger questions.

 

It won't help if you continuously start meaningless discussions and then don't learn anything from them, and then will the same poor understanding in the next discussion.

 

EDIT: Another back of the hand calculation. All the mass in solar system other than Sun itself is about 1/600th of Sun's mass or 2*10³⁰/600 = 3*10²⁷ kg approximately. Now we assume this mass is all in dust particles with density ~2 g/cm³. And also to not bother with distribution through SS we'll jam all these particles within 1 AU from the Sun and 0.5 AU above and below ecliptic. We'll take particles to be ~1mm in size on average.

 

4/3*pi*(0.001)³*2000 = 8*10^-6 kg per particle, hence 3*10²⁷/8*10^-6 = 4*10³² particles

 

Total volume pi*r²*h = 1*10³⁴ m³

 

And then particle density would be ~10^-2 particles/m³.

 

So even in this absolutely unrealistic scenario your idea doesn't stand to scrutiny.

That was a very interesting calculation but I wonder about your estimated thickness of the dust disk 0.5 AU is that 0.25 above and 0.25 AU below. That is a very thick disk isn't it. I'll look into that. I did look through the paper and the maths is difficult. I'm just really throwing alternative ideas around more than really doing all the maths.

 

You have also underestimated the amount of mass in the dust disk. A NASA site said only 15% of the dust disk ends up in the planets the rest is lost to the solar system so you will have to multiply it by at least 8 times.

1 mm of 2g/cm^3 is quite a dense dust too. I'd say that is definitely an over estimate.

Too thick, too dense and an under estimate of the amount of material just as 3 quickfire objections. But it was a brilliant idea to explore the dust density and I will follow this up.

Protoplanetary disks are optically thick. That means that the radiation from the star will not

be able to pass through these disks. Instead, the radiation will be absorbed in the surface layers

of the disk. However, where this radiation is absorbed depends entirely on the geometric shape

of the disk...

 

http://www.ita.uni-heidelberg.de/~dullemond/lectures/leshouches2013.pdf

 

That definitely supports my statement.

Edited February 22, 2016 by Robittybob1

[pavelcherepan]

All of your objections will make up for just around 1 order of magnitude. In my calculation I've jammed all the dust into a volume thousands of times smaller than the actual volume where material was distributed so in reality it will still be very tiny concentration, much lower that what I've shown with the simple calculation.

 

 

That definitely supports my statement.

 

No it doesn't. Again it talks about protoplanetary disks viewed from outside. And it's true, they are not transparent in visible light at least, more so in infra-red.

Edited February 22, 2016 by pavelcherepan