The Lense-Thirring effect - does it affect the orbital inclinations of planets or moons? | AskScience Blog

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Thursday, May 11, 2017

The Lense-Thirring effect - does it affect the orbital inclinations of planets or moons?

The Lense-Thirring effect - does it affect the orbital inclinations of planets or moons?


The Lense-Thirring effect - does it affect the orbital inclinations of planets or moons?

Posted: 11 May 2017 03:28 AM PDT

There's a guy on reddit who insists that the Lense-Thirring effect (L-T) somehow causes the orbital plane of a planet to align with the equatorial plane of the (rotating) star about which the planet orbits. Similarly, the orbital plane of a moon would align itself with the equatorial plane of its host planet, assuming the planet is spinning. He cites this paper to support his thesis.

From what I've read about L-T, this is not the case: the orbital inclination, or the angle between the orbital plane and the equatorial plane, remains the same. However, the orbital plane precesses about the axis of rotation of the star. And there's also nodal precession, too, but that also doesn't affect the angle of the orbital plane.

The one case where L-T does result in something aligning itself with the equatorial plane is in the accretion disks of Kerr black holes: if (for some reason) an accretion disk forms that is out of alignment with a fast-rotating black hole, L-T causes the the orbital planes at different distances to precess at different rates, which causes shearing in the viscous mass of the accretion disk, and as the disk relaxes into a lower energy state, it will end up in the same plane as the plane of rotation of the black hole. But this is due to internal friction within the disk, and that is not a significant factor in ordinary orbital mechanics involving stars, planets, moons, and even rings.

Is he right, or am I? Or are we both wrong?

Edit: concise answers such as "you are right", although appreciated, tend to be too short and will be pruned by automod unless there is some additional supporting argument. Let's not be lazy!

submitted by /u/TheWalruss
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Does a supermassive black hole exist before a galaxy aggregates, and serve as an attractor to create​ the galaxy, or does the supermassive black hole aggregate because of the existing galaxy?

Posted: 10 May 2017 07:01 AM PDT

Since the gravitational force becomes ever smaller as a particle gets farther away from another body of mass, does this gravitational pull become zero at some point or does it become smaller and smaller, never reaching zero?

Posted: 10 May 2017 04:34 PM PDT

From the equations, it seems gravity never becomes a plain zero, therefore all particles are under gravitational influence of all other particles in the universe (even though it is only infinitesimal), but this observation seems weird to me. Anyway, I feel the answer might be attached to wether one considers the universe as infinite or finite.

submitted by /u/meaning_searcher
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Is it possible to convert unpolarized light into linearly polarized light without filtering?

Posted: 10 May 2017 09:02 AM PDT

If I have unpolarized light (for example from the sun) is it possible to convert it to linearly polarized light without any significant losses in intensity?

submitted by /u/anon_1349
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Calorie restriction has been shown to increase the lifespan of mice, dogs and even rhesus monkeys. How does this happen and why can't we apply this to humans?

Posted: 10 May 2017 12:00 PM PDT

If the ageing process can be attributed to an accumulation of toxic byproducts from our diet, couldn't we increase our lifespan by fundamentally changing the way we obtain nutrients e.g. via IV or pills as opposed to eating food?

submitted by /u/hedsortails
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When a seed requires 6 weeks of cold weather to germinate, what makes it take so long -- i.e., what happens at week 6 that didn't happen before, or how does the seed "know"?

Posted: 11 May 2017 07:12 AM PDT

It's not necessarily about freezing, either, as there are seeds that you can germinate in a fridge (staying above freezing).

submitted by /u/michiforjoy
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As CO2 is lighter than water, how come it doesn't leave an open soda bottle in a matter of second?

Posted: 11 May 2017 12:42 AM PDT

Most hydrogen has zero neutrons. Hydrogen fuses to make helium. Most helium has two neutrons. How does that work?

Posted: 10 May 2017 03:04 PM PDT

Why does helium have neutrons if the hydrogen that makes it usually doesn't?

submitted by /u/WaitForItTheMongols
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If dark matter is affected by gravity, why doesn't it form supermassive objects?

Posted: 11 May 2017 06:07 AM PDT

I have heard that dark matter is both uniformly distributed and affected by gravity. How could both of these be true?

submitted by /u/DrugsandGlugs
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Do cancer cells repair DNA damage more efficiently than healthy cells?

Posted: 10 May 2017 01:03 PM PDT

I know that defects in DNA damage repair can initiate malignancy, and I know that efficient DNA repair is one means by which cancer cells resist chemotherapy and radiotherapy. However, I'm not sure if cancer cells, in general, have better DNA repair capacity than healthy cells.

submitted by /u/HolisticReductionist
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Does excess power created by power stations get stored somewhere, or does it continuously run through the lines until it finds a power need?

Posted: 11 May 2017 05:05 AM PDT

Aren't we all(humans, plants, animals, basically everything that is alive on Earth) related?

Posted: 10 May 2017 02:12 PM PDT

Don't we all have a common ancestor?

submitted by /u/Schogon
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Are malignant tissues i.e. cancer the result of one single cell gone awry starting a chain reaction, or are they the result of many cells that go awry at different times and maybe even for different reasons?

Posted: 10 May 2017 10:45 PM PDT

Is a courting process in the animal kingdom considered an uncommon occurrence when it comes to the number of species that have one?

Posted: 11 May 2017 04:27 AM PDT

Is there any theory to predict the likely rotational period (day length) of a planetary body?

Posted: 10 May 2017 04:34 PM PDT

Earth and Mars both have days of about 24 hours. Is this just a coincidence--as seems likely--or is there any kind of theorizing, hypothesizing, or spit-balling to predict rotational periods?

submitted by /u/GeneralTonic
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Could "double eclipses" happen in an exoplanet with two natural satellites orbiting a binary star system?

Posted: 10 May 2017 03:46 PM PDT

If so, do we know of any possible example?

submitted by /u/Pecsus
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We all know penguins live in the south pole, but could they survive at the north?

Posted: 10 May 2017 12:13 PM PDT

Are the environmental conditions (food, predators) similar enough for penguins to live in the northern regions of Earth?

submitted by /u/casc1701
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What is the sum of the first 2017 positive integers, excluding those that are multiples of 2, 3 or 5?

Posted: 10 May 2017 07:52 PM PDT

Presented to grade 6 students in today's Gauss Contest (time allowed about 4 minutes). I have worked on it for a hour without finding a method to do it efficiently.

submitted by /u/Puteh
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What happens to the blood in an uterus during missed periods?

Posted: 10 May 2017 12:11 PM PDT

Let's say a woman misses their period because of stress or other non-pregnancy related reasons. What happens to the blood that accumulated for a month? And what happens to the following cycle? Does the lining keep thickening or does it stay as it is for another full cycle?

submitted by /u/photohooligan
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Do amino acids with similar physical/chemical properties have more similar codons than dissimilar ones?

Posted: 10 May 2017 11:33 AM PDT

I know degeneracy exists, so that mutations, particularly in the third nucleotide of a codon, are more likely to be synonymous.

But are amino acids with similar properties grouped so that a mutation would replace one with another similar to it (and therefore less likely to have a negative effect on protein function)?

If not, why not? It seems a lineage in which this were true would out compete lineages in which it is not.

submitted by /u/ActivisionBlizzard
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