<p>We calculate the jet effect (“nongravitational force”) for active comets, and it’s readily observable. It was observable with 1800s instruments. I’ve never yet seen anyone calculate or search for the effect of the geocorona or magnetotail on a planet.</p>
<p>We calculate the Yarkovsky effect for small (~1 km or less) asteroids. If relevant, we try to measure it. Even then, it takes years to integrate into a measurable value. I’ve never personally seen any claim of a Yarkovsky detection on the large (hundreds of km) asteroids, comets (swamped by NGF, plus the issue of larger orbits), and not any significant (multi-km, and not irregular orbit) moon either. Planets? Hardly.</p>
<p>We calculate the radiation pressure and its net effect for the beta micrometeoroids. <em>B</em> -dust is a few <em>micrometers</em> ; radiation pressure falls exponentially with size and becomes irrelevant for most purposes before a body becomes (directly) visible in telescopes. I could repeat this exercise with Poynting-Robertson, but suffice it to say it’s fairly close. Is there some planet measured in micrometers, not kilometers, I don’t know about?</p>
<p>We don’t even bother with magnetic force. Not on asteroids which are, to a first approximation, magnetically static. Not on comet nuclei, which have an exosphere, ionosphere, and bow shock inflating their effective size. Planets? Please.</p>
<p>Thank you for stating your notion in the form of a question. If you had used the declarative (“The Interplanetary Magnetic Field Influences Planetary Orbits” period) I would have referred you to a different, more appropriate site.</p>

CC BY-SA 4.0
2023-02-12T01:48:34.570Z
Thanks. It is interesting to know that magnetic force effects are so small relative to other effects that they are ignored in those various investigations.  But I am interested in the absolute quantified magnetic forces (however small), as exampled by Keith McLary's calculation (for Sun to Earth), and as formulated by the Yung equation in my question (Update).
steveOw
CC BY-SA 4.0
2023-02-12T01:49:51.497Z
BTW your tone comes over as slightly patronising/sarcastic/disrespectful, which reduces the motivation for further discussion.
steveOw
CC BY-SA 4.0
2023-02-15T21:36:03.257Z
You asked for “quantitative effects”- observable, I presume. You got them (or their nonexistence) and asked again, with more scientism (“trawling through wikipedia”- we investigators rarely bother with that telephone game/roulette table). Free tip: productive people know when to drop an investigation that’s going nowhere, because…
caInstrument
CC BY-SA 4.0
2023-02-15T21:47:28.543Z
“If I have a thousand ideas and only one turns out to be good, I am satisfied.” - Alfred Nobel  “The best way to have a good idea is to have a lot of ideas.” Linus Pauling  ‘I have a thousand ideas, to have one good one.’ Ingvar Kamprad (paraphrased)  Investigators and innovators- successful ones- don’t have ‘lightning strike’ ideas, they have the skill and experience to chug past 950 or so bad ideas, ~30 or so mediocres, and whew, a few of potential. Do you? It’s not really our job to help you from idea #40 to #400; clearly not to babysit you from #2 to #3, and not if you don’t know it’s #2.
caInstrument
CC BY-SA 4.0
2023-02-15T21:56:30.670Z
Hence, our (recognition of and) rejection of _idée fixe_ . In this particular case, you admittedly did not mention “Electric Universe,” and I could not (and did not) fault you for that. But you’re awfully reminiscent of EU flabbajabba, and _idée fixe_ insistences don’t give any better impressions and optics. Again: “I can’t tell you how many dozens or hundreds of my pet ideas have gone to the laboratory _and died_ . And that’s valuable knowledge, you know, to realize which of your ideas are wrong or ideas are childish or ideas are naive.” -Prof. David Dunning… yes, THAT Dunning
caInstrument
CC BY-SA 4.0
2023-02-27T14:42:41.947Z
As I said above "I am interested in the absolute quantified magnetic forces (however small), as exampled by Keith McLary's calculation (for Sun to Earth), and as formulated by the Yung equation in my question ".  If you are able to provide a better theoretical/model- based quantified prediction of the forces  (or a formula for doing so), than those provided so far, please do.
steveOw
CC BY-SA 4.0
2023-02-27T14:47:45.677Z
BTW this is "Stack Exchange - Astronomy" not "... - Space Exploration".  You seem to have become oddly-fixated with the notion that I am proposing something.  But I am simply asking a pure scientific question.
steveOw
CC BY-SA 4.0
2023-01-10T17:36:10.323Z
2023-01-10T17:36:10.323Z
caInstrument
<p><strong>UPDATE</strong></p>
<p>So, you are (sheepishly) using the declarative sense:</p>
<p>“ Their analysis is too far beyond my current knowledge of physics for me to extrapolate to the case of the modern Solar System. But it does suggest to me that ”</p>
<p>At what point do you grasp that WE DO NOT BOTHER WITH THE IMF ON THE ORBITS OF THE PLANETS AND ASTEROIDS?</p>
<p>We aim our missions at the planets and asteroids, and could arrive with order 10,000 km accuracy using ‘60s technology and one course correction burn. This was when we barely understood the IMF, at least in any quantitative way hat held up. Since then, we perform a second correction (well after sep from launch vehicle, which had warranted the first burn), and reach the target with order 1,000 km accuracy… all without bothering with the IMF. In the case of orbiters and landers, we do additional burns for more accuracy… all WITHOUT BOTHERING WITH THE IMF.</p>
<p>You don’t need to look up any more data: you need to look up <em>idée fixe</em> .</p>

CC BY-SA 4.0
2023-02-11T04:59:55.937Z
What's the point of posting a separate answer?
Nilay Ghosh
CC BY-SA 4.0
2023-02-15T21:24:55.510Z
Some people can’t be told… or can’t be bothered to read the _first_ answer. They UPDATE anyway. Henxe, _la  idée fixe_ .Science is not just a search for evidence; it’s a pursuit of well-posed questions that then permit proof _AND_ disproof (…and occasionally one isn’t disproven- yay!) steveOw has finally admitted his question (“effects …on the orbits”) doesn’t hold up to industry practice- seventy years of best practice, by some of our top minds.
caInstrument
CC BY-SA 4.0
2023-02-10T20:02:29.163Z
2023-02-10T20:02:29.163Z
caInstrument
<p><strong>CONTEXT</strong></p>
<p>The equation <span class="math-container">$F_D=\frac{GMm}{D^2}$</span> is a standard equation in Newtonian gravitation. It describes the centripetal force exerted, by a source mass<span class="math-container">$M$</span>, on a target particle of mass <span class="math-container">$m$</span>  located at distance <span class="math-container">$D$</span>. Here <span class="math-container">$G$</span> is Newton's Universal Constant of Gravitation.</p>
<p>The Non-Newtonian Apsidal Rotation Anomalies ( aka &quot;Perihelion Precession&quot;, first observed by LeVerrier for Mercury) observed in planetary orbits are explained by General Relativity. For example the formula <span class="math-container">$F_D=\frac{GMm}{D^2}*\left(1 + \frac{3GM.P}{C^2}\frac{1}{D^2} \right)$</span>  where <span class="math-container">$P$</span> is the semi-latus rectum of the elliptical orbit of the target and <span class="math-container">$C$</span> is the speed of light.</p>
<p>However it is known (e.g. <a href="https://arxiv.org/abs/1106.1568" rel="nofollow noreferrer">Wells 2011</a> ) that Apsides Rotation anomalies (in the context of perihelion precession, very similar to those from GR) can also be generated from an alternative, hypothetical, model by invoking a supra-Newtonian <strong>inverse-distance-cubed</strong> force, independent of <span class="math-container">$P$</span>; as per the following equation:-
<span class="math-container">$F_D=\frac{GMm}{D^2} *\left(1 + \frac{K}{D} \right)$</span> where <span class="math-container">$K=\frac{6.GM}{C^2}$</span>. At the distance of Earth the additional force is ~ <span class="math-container">$6*10^{-11}$</span> times the Newtonian force.</p>
<p>According to <a href="https://en.wikipedia.org/wiki/Sun#Magnetic_field" rel="nofollow noreferrer">wikipedia</a>:-</p>
<blockquote>
<p>The Sun's Dipole Magnetic Field of 50–400 μT (at the photosphere) reduces with the inverse-cube of the distance to about 0.1 nT at the distance of Earth. However, according to spacecraft observations the Interplanetary Magnetic Field at Earth's location is around 5 nT, about a hundred times greater (see Figs 11,12 in <a href="https://arxiv.org/abs/1002.2934" rel="nofollow noreferrer">Svalgaard &amp; Cliver 2010</a> ). The difference is due to magnetic fields generated by electrical currents in the plasma surrounding the Sun.</p>
</blockquote>
<p>A paper by <a href="https://iopscience.iop.org/article/10.1088/0004-637X/745/1/2" rel="nofollow noreferrer">Laine &amp; Lin 2011</a> considers long-term angular orbital momentum transfer through electromagnetic interactions between Stellar Magnetic Fields and close-in Super Earths.</p>
<blockquote>
<p>The source of energy is the differential motion between the (close-in Super-Earth) planet and the magnetosphere of its host star. The Lorentz force on the planet and its host star leads to an evolution toward a state of synchronous rotation. Inside the corotation radius, planets tend to lose angular momentum and migrate inward and the opposite trend occurs outside the corotation radius. Consequently, planets inside corotation migrate inward and those outside corotation migrate outward.</p>
</blockquote>
<p>Their analysis is too far beyond my current knowledge of physics for me to extrapolate to the case of the modern Solar System. But it does suggest to me that electromagnetic interactions between the Sun and its rocky satellites may lead to transfer of angular momentum from the former to the latter.</p>
<p><strong>QUESTION</strong></p>
<p>(a) How does the Interplanetary Magnetic Field (IMF) vary with distance from the Sun (e.g. does it decay in strength with distance in proportion to <span class="math-container">$1/D^3$</span> ?, what is the orientation of <span class="math-container">$B$</span>?, ...)</p>
<p>(b) what quantitative effects does the present Solar System IMF have on the orbits of the planets and asteroids?</p>
<p><strong>UPDATE</strong></p>
<p>After a bit more trawling through wikipedia I guess that the problem can be modelled (initially) in terms of the <a href="https://en.wikipedia.org/wiki/Magnetic_dipole%E2%80%93dipole_interaction" rel="nofollow noreferrer">force between two magnetic dipoles</a>. The force exerted on <span class="math-container">$m_2$</span> is given by:-
<span class="math-container">$$F = \frac{3\mu_0}{4\pi |r|^4}((\hat{r}*m_1)*m_2+(\hat{r}*m_2)*m_1-2\hat{r}(m_1. m_2)+5\hat{r}((\hat{r}*m_1).(\hat{r}*m_2))$$</span>
where <span class="math-container">$r$</span> is the relative position vector, <span class="math-container">$m_1,m_2$</span> are the magnetic moment vectors and <span class="math-container">$\mu_0$</span> is the vacuum permeability or magnetic constant.</p>
<p>An alternative, equivalent formula given by <a href="http://downloads.hindawi.com/archive/1998/079537.pdf" rel="nofollow noreferrer">Yung et al, equation 37, 1998</a> for the force exerted by <span class="math-container">$m_1$</span> on <span class="math-container">$m_2$</span> is:-</p>
<p><span class="math-container">$$F = \frac{3\mu_0 |m_1| |m_2|}{4\pi |r|^4}\left(
\hat{r}(\hat{m_1}.\hat{m_2})
+\hat{m_1}(\hat{r}.\hat{m_2}) 
+\hat{m_2}(\hat{r}.\hat{m_1}) 
-5\hat{r}(\hat{r}.\hat{m_1}).(\hat{r}.\hat{m_2})
\right)$$</span></p>
<p>Note that the magnitude of the dipole-to-dipole force varies in proportion to <span class="math-container">$1/r^4$</span>.</p>
<p>The dipoles will also exert <a href="https://en.wikipedia.org/wiki/Magnetic_moment#Effects_of_an_external_magnetic_field" rel="nofollow noreferrer">torques</a> on each other. The torque exerted by dipole 1 on dipole 2 is given by:- <span class="math-container">$$\tau = m_2 * B_1$$</span>.</p>
<p><strong>Magnetic Dipole Moments for some Solar System Objects</strong></p>
<p>0 3.5 * 10^29 N-m/T Sol</p>
<p>1 3.8 * 10^19 N-m/T Mercury</p>
<p>2 8.0 * 10^17 N-m/T Venus</p>
<p>3 7.98 * 10^22 N-m/T Earth</p>
<p>4 2.1 * 10^18 N-m/T Mars</p>
<p>5 N/A Ceres</p>
<p>6 1.55 * 10^27 N-m/T Jupiter</p>
<p>7 4.6 * 10^25 N-m/T Saturn</p>
<p>8 3.0 * 10^24 N-m/T Uranus</p>
<p>9 1.5 * 10^24 N-m/T Neptune</p>
<p>Source <a href="https://www.physicsforums.com/threads/dipole-moments-of-the-planets-and-the-sun.268157/" rel="nofollow noreferrer">https://www.physicsforums.com/threads/dipole-moments-of-the-planets-and-the-sun.268157/</a></p>
<p><strong>Interplanetary Magnetic Field</strong></p>
<p>User /u/uhoh pointed out in a different question that the IMF has a major effect on the Sun's magnetic influence.</p>
<p>From <a href="https://en.wikipedia.org/wiki/Interplanetary_magnetic_field" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Interplanetary_magnetic_field</a>:-</p>
<blockquote>
<p>The plasma in the interplanetary medium is also responsible for the strength of the Sun's magnetic field at the orbit of the Earth being over 100 times greater than originally anticipated. If space were a vacuum, then the Sun's magnetic dipole field — about 10−4 teslas at the surface of the Sun — would reduce with the inverse cube of the distance to about 10−11 teslas. But satellite observations show that it is about 100 times greater at around 10−9 teslas. Magnetohydrodynamic (MHD) theory predicts that the motion of a conducting fluid (e.g., the interplanetary medium) in a magnetic field induces electric currents, which in turn generates magnetic fields — and, in this respect, it behaves like an MHD dynamo.</p>
</blockquote>
<blockquote>
<p>The interplanetary magnetic field at the Earth's orbit varies with waves and other disturbances in the solar wind, known as &quot;space weather.&quot; The field is a vector, with components in the radial and azimuthal directions as well as a component perpendicular to the ecliptic. The field varies in strength near the Earth from 1 to 37 nT, averaging about 6 nT.[5]</p>
</blockquote>

CC BY-SA 4.0
2020-01-29T17:00:24.413Z
Dipole fields go as 1/r^3, so this will be very weak outside the innermost part of the solar system. Also, the solar field reverses every 11 years while planet fields do not: whatever the orbital interaction is, it will tend to average out unless there is a resonance.
Anders Sandberg
CC BY-SA 4.0
2020-01-29T18:51:15.137Z
@Anders Sandberg A $K/r^3$ centripetal force is enough to account for observed Non-Newtonian planetary precession (out to Mars at least) so long as K has the right value.  But is the larger-than-expected IMF field a simple dipole field? Good point about Solar Field reversal (and fluctuation in field intensity) - I suppose any mechanism of progressive, long-term, Sun to planet, angular momentum transfer is going to have to be rather more complex than a simple, steady, linear, moving-charged-particle-in-a-magnetic-field kind of effect.
steveOw
CC BY-SA 4.0
2021-06-17T04:42:43.483Z
I [calculated the magnetic force between the Earth and Sun to be 5 Newtons](https://astronomy.stackexchange.com/a/29731/17743), about one pound weight.
Keith McClary
CC BY-SA 4.0
2021-06-22T15:49:37.500Z
@Keith McClary Thanks. 5N is ~ 5/(3.6*10^22) = ~1.4*10^-22 of the gravitational force of the Sun on the Earth.  Which is much less than the ~6*10^-11 force ratio required to account for the non-Newtonian Apsidal Rotation of the Earth's orbit predicted by GR.
steveOw
<gravity><magnetic-field><solar-system-evolution>
What influence does the Interplanetary Magnetic Field have on Planetary Orbits?
steveOw
# What influence does the Interplanetary Magnetic Field have on Planetary Orbits?

(Asked by: username_0 on 2020-01-28)

**CONTEXT**

The equation $F\_D=\frac{GMm}{D^2}$ is a standard equation in Newtonian gravitation. It describes the centripetal force exerted, by a source mass$M$, on a target particle of mass $m$ located at distance $D$. Here $G$ is Newton's Universal Constant of Gravitation.

The Non-Newtonian Apsidal Rotation Anomalies ( aka "Perihelion Precession", first observed by LeVerrier for Mercury) observed in planetary orbits are explained by General Relativity. For example the formula $F\_D=\frac{GMm}{D^2}\*\left(1 + \frac{3GM.P}{C^2}\frac{1}{D^2} \right)$ where $P$ is the semi-latus rectum of the elliptical orbit of the target and $C$ is the speed of light.

However it is known (e.g. [Wells 2011](https://arxiv.org/abs/1106.1568) ) that Apsides Rotation anomalies (in the context of perihelion precession, very similar to those from GR) can also be generated from an alternative, hypothetical, model by invoking a supra-Newtonian **inverse-distance-cubed** force, independent of $P$; as per the following equation:-
$F\_D=\frac{GMm}{D^2} \*\left(1 + \frac{K}{D} \right)$ where $K=\frac{6.GM}{C^2}$. At the distance of Earth the additional force is ~ $6\*10^{-11}$ times the Newtonian force.

According to [wikipedia](https://en.wikipedia.org/wiki/Sun#Magnetic_field):-

> The Sun's Dipole Magnetic Field of 50–400 μT (at the photosphere) reduces with the inverse-cube of the distance to about 0.1 nT at the distance of Earth. However, according to spacecraft observations the Interplanetary Magnetic Field at Earth's location is around 5 nT, about a hundred times greater (see Figs 11,12 in [Svalgaard & Cliver 2010](https://arxiv.org/abs/1002.2934) ). The difference is due to magnetic fields generated by electrical currents in the plasma surrounding the Sun.

A paper by [Laine & Lin 2011](https://iopscience.iop.org/article/10.1088/0004-637X/745/1/2) considers long-term angular orbital momentum transfer through electromagnetic interactions between Stellar Magnetic Fields and close-in Super Earths.

> The source of energy is the differential motion between the (close-in Super-Earth) planet and the magnetosphere of its host star. The Lorentz force on the planet and its host star leads to an evolution toward a state of synchronous rotation. Inside the corotation radius, planets tend to lose angular momentum and migrate inward and the opposite trend occurs outside the corotation radius. Consequently, planets inside corotation migrate inward and those outside corotation migrate outward.

Their analysis is too far beyond my current knowledge of physics for me to extrapolate to the case of the modern Solar System. But it does suggest to me that electromagnetic interactions between the Sun and its rocky satellites may lead to transfer of angular momentum from the former to the latter.

**QUESTION**

(a) How does the Interplanetary Magnetic Field (IMF) vary with distance from the Sun (e.g. does it decay in strength with distance in proportion to $1/D^3$ ?, what is the orientation of $B$?, ...)

(b) what quantitative effects does the present Solar System IMF have on the orbits of the planets and asteroids?

**UPDATE**

After a bit more trawling through wikipedia I guess that the problem can be modelled (initially) in terms of the [force between two magnetic dipoles](https://en.wikipedia.org/wiki/Magnetic_dipole%E2%80%93dipole_interaction). The force exerted on $m\_2$ is given by:-
$$F = \frac{3\mu\_0}{4\pi |r|^4}((\hat{r}\*m\_1)\*m\_2+(\hat{r}\*m\_2)\*m\_1-2\hat{r}(m\_1. m\_2)+5\hat{r}((\hat{r}\*m\_1).(\hat{r}\*m\_2))$$
where $r$ is the relative position vector, $m\_1,m\_2$ are the magnetic moment vectors and $\mu\_0$ is the vacuum permeability or magnetic constant.

An alternative, equivalent formula given by [Yung et al, equation 37, 1998](http://downloads.hindawi.com/archive/1998/079537.pdf) for the force exerted by $m\_1$ on $m\_2$ is:-

$$F = \frac{3\mu\_0 |m\_1| |m\_2|}{4\pi |r|^4}\left(
\hat{r}(\hat{m\_1}.\hat{m\_2})
+\hat{m\_1}(\hat{r}.\hat{m\_2})
+\hat{m\_2}(\hat{r}.\hat{m\_1})
-5\hat{r}(\hat{r}.\hat{m\_1}).(\hat{r}.\hat{m\_2})
\right)$$

Note that the magnitude of the dipole-to-dipole force varies in proportion to $1/r^4$.

The dipoles will also exert [torques](https://en.wikipedia.org/wiki/Magnetic_moment#Effects_of_an_external_magnetic_field) on each other. The torque exerted by dipole 1 on dipole 2 is given by:- $$\tau = m\_2 \* B\_1$$.

**Magnetic Dipole Moments for some Solar System Objects**

0 3.5 \* 10^29 N-m/T Sol

1 3.8 \* 10^19 N-m/T Mercury

2 8.0 \* 10^17 N-m/T Venus

3 7.98 \* 10^22 N-m/T Earth

4 2.1 \* 10^18 N-m/T Mars

5 N/A Ceres

6 1.55 \* 10^27 N-m/T Jupiter

7 4.6 \* 10^25 N-m/T Saturn

8 3.0 \* 10^24 N-m/T Uranus

9 1.5 \* 10^24 N-m/T Neptune

Source <https://www.physicsforums.com/threads/dipole-moments-of-the-planets-and-the-sun.268157/>

**Interplanetary Magnetic Field**

User /u/uhoh pointed out in a different question that the IMF has a major effect on the Sun's magnetic influence.

From <https://en.wikipedia.org/wiki/Interplanetary_magnetic_field>:-

> The plasma in the interplanetary medium is also responsible for the strength of the Sun's magnetic field at the orbit of the Earth being over 100 times greater than originally anticipated. If space were a vacuum, then the Sun's magnetic dipole field — about 10−4 teslas at the surface of the Sun — would reduce with the inverse cube of the distance to about 10−11 teslas. But satellite observations show that it is about 100 times greater at around 10−9 teslas. Magnetohydrodynamic (MHD) theory predicts that the motion of a conducting fluid (e.g., the interplanetary medium) in a magnetic field induces electric currents, which in turn generates magnetic fields — and, in this respect, it behaves like an MHD dynamo.

> The interplanetary magnetic field at the Earth's orbit varies with waves and other disturbances in the solar wind, known as "space weather." The field is a vector, with components in the radial and azimuthal directions as well as a component perpendicular to the ecliptic. The field varies in strength near the Earth from 1 to 37 nT, averaging about 6 nT.[5]

**Tags:** gravity, magnetic-field, solar-system-evolution
> **Comments:**
> **username_1**: Dipole fields go as 1/r^3, so this will be very weak outside the innermost part of the solar system. Also, the solar field reverses every 11 years while planet fields do not: whatever the orbital interaction is, it will tend to average out unless there is a resonance.  
> **username_0**: @Anders Sandberg A $K/r^3$ centripetal force is enough to account for observed Non-Newtonian planetary precession (out to Mars at least) so long as K has the right value.  But is the larger-than-expected IMF field a simple dipole field? Good point about Solar Field reversal (and fluctuation in field intensity) - I suppose any mechanism of progressive, long-term, Sun to planet, angular momentum transfer is going to have to be rather more complex than a simple, steady, linear, moving-charged-particle-in-a-magnetic-field kind of effect.  
> **username_2**: I [calculated the magnetic force between the Earth and Sun to be 5 Newtons](https://astronomy.stackexchange.com/a/29731/17743), about one pound weight.  
> **username_0**: @Keith McClary Thanks. 5N is ~ 5/(3.6*10^22) = ~1.4*10^-22 of the gravitational force of the Sun on the Earth.  Which is much less than the ~6*10^-11 force ratio required to account for the non-Newtonian Apsidal Rotation of the Earth's orbit predicted by GR.  

---

## 2 answers

### Answer by username_3 on 2023-01-10. Score: 1

We calculate the jet effect (“nongravitational force”) for active comets, and it’s readily observable. It was observable with 1800s instruments. I’ve never yet seen anyone calculate or search for the effect of the geocorona or magnetotail on a planet.

We calculate the Yarkovsky effect for small (~1 km or less) asteroids. If relevant, we try to measure it. Even then, it takes years to integrate into a measurable value. I’ve never personally seen any claim of a Yarkovsky detection on the large (hundreds of km) asteroids, comets (swamped by NGF, plus the issue of larger orbits), and not any significant (multi-km, and not irregular orbit) moon either. Planets? Hardly.

We calculate the radiation pressure and its net effect for the beta micrometeoroids. *B* -dust is a few *micrometers* ; radiation pressure falls exponentially with size and becomes irrelevant for most purposes before a body becomes (directly) visible in telescopes. I could repeat this exercise with Poynting-Robertson, but suffice it to say it’s fairly close. Is there some planet measured in micrometers, not kilometers, I don’t know about?

We don’t even bother with magnetic force. Not on asteroids which are, to a first approximation, magnetically static. Not on comet nuclei, which have an exosphere, ionosphere, and bow shock inflating their effective size. Planets? Please.

Thank you for stating your notion in the form of a question. If you had used the declarative (“The Interplanetary Magnetic Field Influences Planetary Orbits” period) I would have referred you to a different, more appropriate site.

> **Comments:**
> **username_0**: Thanks. It is interesting to know that magnetic force effects are so small relative to other effects that they are ignored in those various investigations.  But I am interested in the absolute quantified magnetic forces (however small), as exampled by Keith McLary's calculation (for Sun to Earth), and as formulated by the Yung equation in my question (Update).  
> **username_0**: BTW your tone comes over as slightly patronising/sarcastic/disrespectful, which reduces the motivation for further discussion.  
> **username_3**: You asked for “quantitative effects”- observable, I presume. You got them (or their nonexistence) and asked again, with more scientism (“trawling through wikipedia”- we investigators rarely bother with that telephone game/roulette table). Free tip: productive people know when to drop an investigation that’s going nowhere, because…  
> **username_3**: “If I have a thousand ideas and only one turns out to be good, I am satisfied.” - Alfred Nobel  “The best way to have a good idea is to have a lot of ideas.” Linus Pauling  ‘I have a thousand ideas, to have one good one.’ Ingvar Kamprad (paraphrased)  Investigators and innovators- successful ones- don’t have ‘lightning strike’ ideas, they have the skill and experience to chug past 950 or so bad ideas, ~30 or so mediocres, and whew, a few of potential. Do you? It’s not really our job to help you from idea #40 to #400; clearly not to babysit you from #2 to #3, and not if you don’t know it’s #2.  
> **username_3**: Hence, our (recognition of and) rejection of _idée fixe_ . In this particular case, you admittedly did not mention “Electric Universe,” and I could not (and did not) fault you for that. But you’re awfully reminiscent of EU flabbajabba, and _idée fixe_ insistences don’t give any better impressions and optics. Again: “I can’t tell you how many dozens or hundreds of my pet ideas have gone to the laboratory _and died_ . And that’s valuable knowledge, you know, to realize which of your ideas are wrong or ideas are childish or ideas are naive.” -Prof. David Dunning… yes, THAT Dunning  
> **username_0**: As I said above "I am interested in the absolute quantified magnetic forces (however small), as exampled by Keith McLary's calculation (for Sun to Earth), and as formulated by the Yung equation in my question ".  If you are able to provide a better theoretical/model- based quantified prediction of the forces  (or a formula for doing so), than those provided so far, please do.  
> **username_0**: BTW this is "Stack Exchange - Astronomy" not "... - Space Exploration".  You seem to have become oddly-fixated with the notion that I am proposing something.  But I am simply asking a pure scientific question.  

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### Answer by username_3 on 2023-02-10. Score: -2

**UPDATE**

So, you are (sheepishly) using the declarative sense:

“ Their analysis is too far beyond my current knowledge of physics for me to extrapolate to the case of the modern Solar System. But it does suggest to me that ”

At what point do you grasp that WE DO NOT BOTHER WITH THE IMF ON THE ORBITS OF THE PLANETS AND ASTEROIDS?

We aim our missions at the planets and asteroids, and could arrive with order 10,000 km accuracy using ‘60s technology and one course correction burn. This was when we barely understood the IMF, at least in any quantitative way hat held up. Since then, we perform a second correction (well after sep from launch vehicle, which had warranted the first burn), and reach the target with order 1,000 km accuracy… all without bothering with the IMF. In the case of orbiters and landers, we do additional burns for more accuracy… all WITHOUT BOTHERING WITH THE IMF.

You don’t need to look up any more data: you need to look up *idée fixe* .

> **Comments:**
> **username_4**: What's the point of posting a separate answer?  
> **username_3**: Some people can’t be told… or can’t be bothered to read the _first_ answer. They UPDATE anyway. Henxe, _la  idée fixe_ .Science is not just a search for evidence; it’s a pursuit of well-posed questions that then permit proof _AND_ disproof (…and occasionally one isn’t disproven- yay!) steveOw has finally admitted his question (“effects …on the orbits”) doesn’t hold up to industry practice- seventy years of best practice, by some of our top minds.  

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