Could Asteroid Strikes Affect Mercury's Perihelion Advance?

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SUMMARY

The discussion centers on the precession of Mercury's perihelion and the misconception that asteroid strikes could account for discrepancies in its orbit. Participants assert that Einstein's general relativity adequately explains this phenomenon through an additional 1/r^4 term in the gravitational force equation. The consensus is that the effects of asteroid impacts are statistically insignificant and cannot provide the necessary kinetic energy to alter Mercury's orbit in the required manner. Furthermore, the discussion emphasizes the importance of understanding established scientific principles before proposing alternative theories.

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  • Understanding of Einstein's General Relativity and its implications on planetary motion.
  • Familiarity with Newtonian gravity and orbital mechanics.
  • Knowledge of gravitational force equations, particularly the 1/r^2 and 1/r^4 terms.
  • Basic concepts of kinetic energy and its effects on celestial bodies.
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  • Study Einstein's General Relativity and its applications to planetary motion.
  • Learn about the mathematical formulation of gravitational forces, including the derivation of the 1/r^4 term.
  • Investigate the historical context and experimental validations of general relativity.
  • Explore the role of asteroid impacts in planetary geology and surface features.
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Astronomy students, physicists, and anyone interested in the dynamics of celestial mechanics and the implications of general relativity on planetary orbits.

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TL;DR
Newton's equations predict planet Mercury's perihelion precession 5557 arc seconds Vs actual precession measured was 5600 arc seconds per century. By general relativity, Einstein had solved the problem discrepancy of 43 arcs second per century by introducing the wrapping of space-time due to Sun. However, the predicted magnitude for other planets was not satisfied. Is it possible that the additional force required for precession caused by asteroids' regular striking force?
Einstein had solved the problem by introducing wrapping of space-time due to Sun as per general relativity. However, the predicted magnitude for other planets like Venus, Earth. Is it possible that additional force required for precession is due to asteroids striking force?
 
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Where are all these asteroids coming from?
 
The precession of the perhelion of Mercury as predicted from General relativity comes from an approximate correction to Newtonian gravity with an additional 1/r^4 term added on top of the usual 1/r^2 force law.

In the orbiting frame of reference:
F(r)\approx(-\frac{GMm}{r^{2}} - \frac{3G(M+m) L^{2}}{c^2\mu r^{4}})+\frac{L^{2}}{\mu r^{3}}
where the cubic term outside the parentheses is just the centrifugal force coming from being in the rotating (orbiting) frame of reference.

With Mercury being closest to the sun, the effect of the 1/r^4 term will be strongest, and will get weaker rapidly at larger distance from the Sun. This is why Venus, Earth, and the rest of the planets don't really need general relativity to predict their obits accurately on the century scale. For long enough times, the effects of General relativity would have to change the predicted trajectories of even the outer planets, but the amount of this change is very small unless you go to truly long time scales.
 
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rajen0201 said:
However, the predicted magnitude for other planets was not satisfied.
Do you have a reference for this? Modern observations suggest that the precessions match very well. This paper: https://arxiv.org/abs/0710.2610v1 has data it says comes from this one: https://link.springer.com/article/10.1134/1.1922533. I can only see the abstract of the latter, but it concludes "The results obtained show a remarkable correspondence of the planetary motions [...] to General Relativity"
 
Vanadium 50 said:
Where are all these asteroids coming from?
Due to Sun gravitational force. We know that Mercury's surface is fully covered with asteroid craters. Mercury is nearest planet in solar system So, it has very high chances that it come across an asteroid.
 
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You have got to be kidding.

How many impacts do you think is necessary to do this?
 
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Not to mention the fundamental problem that you need relativity to be wrong for there to be a problem with Mercury's orbit for you to solve using asteroids. If you don't believe the predictions of relativity then you need to explain all the observed effects normally explained in relativistic terms: Shapiro delay, gravitational redshift, gravitational lensing, gravitational waves, more or less all of cosmology. Using asteroids.
 
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Vanadium 50 said:
How many impacts do you think is necessary to do this?

I worked this out, only you should have -if this is A-level there is no excuse for you not to have done so. It takes ~2 dinosaur killers per day (hitting in the exact right spot, of course) to do this. The energy is more than enough to melt the surface.
 
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Couple of other basic problems here:
1] To be responsible for the precession, the asteroids that would have to add net kinetic energy in the direction of its revolution. This is statistically unlikely. On average, due to Mecury's own motion, the asteroids should be adding kinetic energy in the opposite direction.

2] If it were simply a matter of Newtonian orbital mechanics, any KE added to the Mercury system would result in its orbit widening - or at least becoming more eccentric - rather than precessing.

* see caveat in sig line
 
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Vanadium 50 said:
I worked this out, only you should have -if this is A-level there is no excuse for you not to have done so. It takes ~2 dinosaur killers per day (hitting in the exact right spot, of course) to do this. The energy is more than enough to melt the surface.
I'm pretty sure op is probably a kid and/or doesn't really know enough physics to know what is considered advanced or a feasible explanation.

To the op, the problem you are posing has been more or less explained by Einstein's general relativity just fine and it's a theory that we have tested in many ways and has been highly successful, it can't really be explained by asteroid strikes for many reasons (including but not limited to what Vanadium 50 said, also one would expect that asteroid strikes would be at least somewhat uniformly distributed at this point, so there isn't really much of a reason to have that big an effect on Mercury's perihelium as asteroids would also be hitting Mercury the other way, also the surface looks like that because there is practically no atmosphere or volcanic activity to hide the craters, it's not like Mercury just gets pelted by asteroids all the time).
 
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AndreasC said:
I'm pretty sure op is probably a kid and/or doesn't really know enough physics to know what is considered advanced or a feasible explanation.
Possibly - in which case we should point out to @rajen0201 that tagging a thread "A" means that you claim to have postgraduate level knowledge in the topic you want to discuss, and expect answers at that level. As @Vanadium 50 points out, someone with that skill level can see easily why your idea is clearly wrong. Perhaps you should tag your threads as "I" or "B" level? You are more likely to get helpful replies if you tag your threads appropriately.
 
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  • #12
@rajen0201 When you come up with an idea that seems to completely be against established science, it is not a good idea to start off questioning established science but rather to start off with the assumption that you have made a mistake somewhere and try to find out where it is. If you have NOT made a mistake you will find the flaw in the established science, but that is extraordinarily unlikely to happen. If you start off thinking that you have overturned established science you are likely to just end up embarrassed.

Also, thinking outside the box is an admirable activity, BUT ... first you have to learn what's IN the box.
 
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  • #13
The thread level has been set to “B“, appropriate for the total lack of quantitative thinking in the original post.

The thread is closed, and OP, you are urged to pay particular attention to post #7.
 
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