Researchers suggest dark matter disk in Milky Way plane could signal rash of comet strikes on Earth

Researchers suggest dark matter disk in Milky Way plane could signal rash of comet strikes on Earth
Our Solar System orbits around the Milky Way’s center, completing a revolution every 250 million years or so. Along this path, it oscillates up and down, crossing the galactic plane about every 32 million years. If a dark matter disk were concentrated along the galactic plane, as shown here, it might tidally disrupt the motion of comets in the Oort cloud at the outer edge of our Solar System. This could explain possible periodic fluctuations in the rate of impacts on Earth. Credit: Physics 7, 41 (2014) | DOI: 10.1103/Physics.7.41

(Phys.org) —A pair of researchers at Harvard University has published a paper in the journal Physical Review Letters, in which they suggest that a dark matter disk hiding in the Milky Way plane might be responsible for causing asteroids or comets to head our way. In their paper, Lisa Randall and Matthew Reece suggest that such a dark matter disk could pull other bodies from the Oort cloud, some of which could wind up heading toward Earth.

It has been noted by scientists that asteroids and comets tend to strike the Earth in a cyclic pattern that occurs approximately every 35 million—as evidenced by telltale craters. But why such a cycle might occur is still up to conjecture. Some have suggested it's due to a mysterious planet hidden from our view, or perhaps the presence of an as yet undiscovered companion star. In this new effort, the research duo suggests it might be due to the of a disk residing in the Milky Way Galaxy plane.

This is not the first time that scientists have suggested such a disk might exist—it's been suggested that a dark matter a disk would explain why our galaxy doesn't spin apart. It is the first time, however, that such a disk has been proposed as an answer to why our planet gets bombarded periodically with asteroids or comets.

In their paper, Randall and Reece note that the conventional view of the material that makes up dark matter, wouldn't work as a means of pulling other bodes from where they currently reside, it's evident in their name—weakly interacting massive particles. They suggest that some dark matter could be made instead of what they describe as "strong electromagnetic-like interactions among " which by their nature would exert a greater gravitational pull. And if that were the case, then it would seem plausible that as our solar system circles around the center of our galaxy, most particularly as we move closer to the Oort cloud, some of those bodies that exist there, could be jostled, which in turn could cause some of them to wind up on a collision course with our planet.

This new theory by the research pair has some problems—it assumes the periodicity of crater creation has been firmly established, which it hasn't, and, scientists aren't even sure which craters on the Earth's surface were cause by what sort of object. In any event, the theory is expected to gain or lose credence as the European Space Agency's Gaia mission gets underway—it's supposed to give us a better view of the Milky Way Galaxy than ever before.


Explore further

Physicists suggest possible existence of other kinds of dark matter

More information: Dark Matter as a Trigger for Periodic Comet Impacts, Phys. Rev. Lett. 112, 161301 – Published 21 April 2014. journals.aps.org/prl/abstract/ … ysRevLett.112.161301

ABSTRACT
Although statistical evidence is not overwhelming, possible support for an approximately 35×106  yr periodicity in the crater record on Earth could indicate a nonrandom underlying enhancement of meteorite impacts at regular intervals. A proposed explanation in terms of tidal effects on Oort cloud comet perturbations as the Solar System passes through the galactic midplane is hampered by lack of an underlying cause for sufficiently enhanced gravitational effects over a sufficiently short time interval and by the time frame between such possible enhancements. We show that a smooth dark disk in the galactic midplane would address both these issues and create a periodic enhancement of the sort that has potentially been observed. Such a disk is motivated by a novel dark matter component with dissipative cooling that we considered in earlier work. We show how to evaluate the statistical evidence for periodicity by input of appropriate measured priors from the galactic model, justifying or ruling out periodic cratering with more confidence than by evaluating the data without an underlying model. We find that, marginalizing over astrophysical uncertainties, the likelihood ratio for such a model relative to one with a constant cratering rate is 3.0, which moderately favors the dark disk model. Our analysis furthermore yields a posterior distribution that, based on current crater data, singles out a dark matter disk surface density of approximately 10M⊙/pc2. The geological record thereby motivates a particular model of dark matter that will be probed in the near future.

Journal information: Physical Review Letters

© 2014 Phys.org

Citation: Researchers suggest dark matter disk in Milky Way plane could signal rash of comet strikes on Earth (2014, May 1) retrieved 14 October 2019 from https://phys.org/news/2014-05-dark-disk-milky-plane-rash.html
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May 01, 2014
Dark matter. Pssh.

May 01, 2014
"No matter how well liked a theory may be, if observation contradicts it, then it must be rejected. For science to be useful, it must provide an increasingly true and deep description of what nature must be." ~ Eric J. Lerner

May 01, 2014
Hey barakn wasn't I just talking about this? We have only recently become able to detect potential impactors. But this does not mean that we are not witnessing a surge in the number of them.

May 01, 2014
The authors are well aware of the assumptions that they are making. PDF of the paper an arXiv: http://arxiv.org/...0576.pdf

May 01, 2014
Hey barakn wasn't I just talking about this? We have only recently become able to detect potential impactors. But this does not mean that we are not witnessing a surge in the number of them.

Yes, indeed we were. But since it takes millenia to pass through even a "thin" dark matter disk, I don't think it can explain dramatic changes in meteorite/asteroid impacts on the order of a few years.

I wouldn't wonder that the dark-matter Bok globules in the spiral plane have an effect, but I have a model for extinction level events caused by Sedna-sized icy-body impacts which contribute continental land mass in the form of aqueously-differentiated rock.

I suggest that the similar arguments of perihelion of extended scattered disk (also called inner Oort cloud) TNOs planetesimals and dwarf planets are not aligned by a _current_ Planet-X as supposed, but rather a _former_ Companion star to the Sun that has 'recently' drifted away.

When extended scattered disk TNOs and dwarf planets and Oort cloud comets further out mutually cross the orbit of our former Companion, their orbits change from barycentric to heliocentric and back again, providing the perturbation mechanism.

Now with the loss of the Companion and its concomitant centrifugal force of the Sun around our former solar-system barycenter, we may be transitioning from an era dominated by icy-body impacts from the outer sol

May 01, 2014
subject to the same gravitational forces which influence the motion of all of the matter in a region? If the disk is there, why doesn't it oscillate as well?
You know, I bet this very question, among many others, occurred also to the researchers, who are after all experts, who did the paper. Why dont you read it and find out?
I don't think it can explain dramatic changes in meteorite/asteroid impacts on the order of a few years
But, AGAIN, we wouldnt know until you actually saw the data now would we? The authors do say this:

"...sufficiently enhanced gravitational effects over a sufficiently short time interval and by the time frame between such possible enhancements. We show that a smooth dark disk in the galactic midplane would address both these issues"

-I suppose it would depend on what they mean by 'short'. Depending on how thin and dense this disk is, the effect could possibly be similar to that of a large perturbing body. The transition could be quite abrupt.

May 01, 2014
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May 01, 2014
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May 01, 2014
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May 01, 2014
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May 01, 2014
I did. It didn't. Perhaps you can point out where you think they address it since you seem to think they have
No I didnt read the paper but I do assume that harvard researchers possess a minimum level of competence. Agreed?

What could possibly make you think that the questions that occur to YOU after spending only a few minutes reading a news release, which are after all pretty freeking OBVIOUS and fundamental questions, wouldnt have occurred to harvard researchers who have spent months writing their paper?

And what makes you think you can ask questions like THAT, without having even bothered to read the paper first, without getting freeking TRASHED for it?

May 01, 2014
Nonsense over nonsense.

May 01, 2014
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May 01, 2014
G.Kanev


G.Knave-Skippy, can you explain that again using normal words? Why you Einstein wannabes think if you say something nobody can understand that everybody or somebody might be fooled into thinking you are one of the smart peoples?

All the really smart peoples can say the things so that other people can understands them. Did you know that Cher? It is true, mon ami, if nobody understand what you say it is a sure sign that everybody is smarter than you, eh?

That's why the Skippys like you are get a silly looking pointy cap to wear for the smart peoples to make fun with. You are got yourself on the list Knave-Skippy, bad karma points for you to go with that silly looking pointy cap on your head that looks so apropos on you Cher.

May 01, 2014
Kanev, your opinions have many valid points (in certain extent they're actually overshooting my own ideas, so I cannot agree with them in full depth), but they're still not so smart for being relevant to the discussion subject at least partially. The off-topic posts dilute the coherence of discussion and its relevance for understanding - no matter how insightful they actually can be in another context. Got it?


@ Zephir-Skippy how you go Neg? That Knave-Skippy is stealing your ideas, eh? The johnpringles-Skippy been stealing them too him over on the paradoxing twin conversations.

May 01, 2014
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May 01, 2014
The inherent property of silly and uninformed people is, they cannot understand more complex ideas. I do understand, what Kanev wanted to say - but from the same reason I can tell safely, it doesn't contribute with anything to the current subject. For example the insight, that the metric expansion of space applies only to local observer fits well with my water surface analogies/explanations of the red shift. It can serve as a strong http://www.scienc...ox-85942 scenario in future. But I cannot agree, that the gravity field of galaxies is modeled with the external galaxies - it applies to cold dark matter only. And many other insights are exaggerated in similar way.


@ Zephir-Skippy it sounds a lot smarter the way you say it for me it does. You must be finally making way against the current, eh? That's two peoples in one day stealing your ideas.

May 01, 2014
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May 01, 2014
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May 01, 2014
Kanev, your opinions have many valid points (in certain extent they're rather overshooting my own ideas, so I cannot agree with them in full depth), but they're still not so smart for being relevant to the discussion subject at least partially. The off-topic posts dilute the coherence of discussion and its relevance for understanding - no matter how insightful they actually can be in another context. Got it?


@ Zephyr
No one, and I mean no one, goes on off topic rants more than you my friend. It simply doesn't matter what topic is being discussed; you find a way to insert AWT or cold fusion or any of your other pet theories into the thread. I think you're a pretty smart guy but you gotta watch who's calling the kettle black!

May 01, 2014
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May 01, 2014
But the central question remains: Why is it necessary to invoke some hypothesised exotic species of DM to produce the gravitational perturbation of objects in the Oort Cloud?

Wouldn't the mere physics of passing through a region of greater mass density --and therefore gravitational force-- be sufficient to produce this effect upon objects that were not only in the OCloud, but that might also just be interpenetrating the solar system?

We pass through the galactic disk simultaneously with its passage through us.


May 01, 2014
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May 01, 2014
How can a disk of matter which exerts a gravitational force NOT be subject to the same gravitational forces which influence the motion of all of the matter in a region? If the disk is there, why doesn't it oscillate as well?


Conjecture 1:
Massless particle nevertheless exerts gravitational force proportional to it's energy level.
Plausibilty: Low, but non-zero.
Problem: Why doesn't it escape the galaxy and diffuse through space?

Conjecture 2:
The "disk" or "halo" is an imaginary construct invented to explain a mis-understanding of Newton's law of gravity, for example, failure to realize a non-zero constant of integration (anti-derivative, not necessarily integral,) is in fact a valid solution to the anti-derivative of the acceleration formula, thereby explaining the flat stellar orbital velocity curve without the existence of a mysterious substance. Nobody even addresses this issue.

A non-zero constant of Integration is in fact a valid solution. Now plot that...

May 01, 2014
Conjecture 1:
Massless particle nevertheless exerts gravitational force proportional to it's energy level.
Plausibilty: Low, but non-zero.
Problem: Why doesn't it escape the galaxy and diffuse through space?


Do you have a name for that theory Returnering-Skippy? Or is it something you pull from your butt Cher?

Conjecture 2:
The "disk" or "halo" is an imaginary construct invented to explain a mis-understanding of Newton's law of gravity, for example, failure to realize a non-zero constant of integration (anti-derivative, not necessarily integral,) is in fact a valid solution to the anti-derivative of the acceleration formula, thereby explaining the flat stellar orbital velocity curve without the existence of a mysterious substance. Nobody even addresses this issue.


Returnering-Skippy, even ol Ira knows they addresseded that issue.

A non-zero constant of Integration is in fact a valid solution. Now plot that...


Why you don't plot it yourself there Skippy?

May 01, 2014
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May 01, 2014
Why you don't plot it yourself there


It produces a slope zero line.

Mre accurately, it shifts the hyperbolic curve of escape velocity upward or downward, but with the limit as r-> infinity being proportional to the constant itself (zero assumed presently,) and then in turn would shift the escape velocity of objects in a system upward or downward.

now if you go back and take a look at that stellar orbital velocity curve and see that it levels out and stays flat, the notion of a hidden constant/semi-constant term in the gravity equation starts to look attractive. It looks like a hyperbolic curve shifted upwards:

y = -GM/r + C

Put that in a graphing calculator or software.

Curve "B", seen in the link, is almost an exact solution in the family "y=-GM/r +C", where C in this case is a positive constant.

http://en.wikiped...ion2.svg

As r gets very big, -GM/r approaches zero, and the curve approaches "C" and stays there.

Viola. An exact match.

May 01, 2014
When you are taught calculus and differentials, it is mentioned a few occasions that values for C (sometimes used K) of non-zero are valid solutions, but because most of the time you're doing a full integral it is assumed the constant cancels itself. However, in the real universe, because "information" is limited by the speed of light, the notion of "information" canceling itself during physical, universal equivalent of an integration is inherently flawed: since "information" can't get from one end of the curve to the other in instantaneous time, it cannot necessarily "cancel" itself, thus a residual constant conceivably can remain either way.

Again, you are taught that these are valid solutions to the antiderivative.

However, in normal science and engineering the constant is always assumed to be zero. This is not necessarily a sound assumption. A valid solution is still a valid solution, even if you think it's over-complicated.

May 01, 2014
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May 01, 2014
So notice, "Y = -GM/r +C" is a negative hyperbolic, shifted upward, which is almost exactly what you see in the curve B on the stellar orbital velocity curve.

The stellar orbital velocity curve is a negative hyperbolic, and is shifted upward by a constant.
The generalized antiderivative of the gravity acceleration formula is a negative hyperbolic curve shifted by a constant.

The two have exactly the same order, so an arbitrary constant, K, (for lack of confusion with c used for speed of light,) fixes the problem exactly, and falls well within the laws of mathematics.

I've pointed this possible explanation out before, and get ridiculed for it, but there is no mathematical reason to discard this solution. It's a very basic and obvious and easily obtainable solution within the known laws of physics, without proposing phantom particles and phantom forces.

May 01, 2014
"....if nobody understand what you say it is a sure sign that everybody is smarter than you, eh?" Uncle Ira

@ Uncle Ira: You keep up the constant prattle about others moving over & making room for listening to "the smart people" posting here. Your posts are among the most frequently appearing of any that appear in this forum taking up a lot of space that could otherwise be allotted to those who sincerely would like to have scientific discussions with others......that is others of those who are of like mind which you obviously are not......so why don't you simply cease with the unintelligible prattle & noise & and make a serious attempt at discussing science with us, or GET OFF THE FORUM.

May 01, 2014
So notice, "Y = -GM/r +C" is a negative hyperbolic, shifted upward, which is almost exactly what you see in the curve B on the stellar orbital velocity curve.


I just try to check out what you think know and run up on a problem with this, and if this a piece you got the very wrong then everything that come before and after it is wrong too Cher.

Ol Ira-Skippy found that the google-Skippy says you don't know what you talking about Returnering-Skippy. The google-Skippy says that thing you write there is not the right way to write the hyperbolic anything. So you just making this up out of your butt there Skippy-Doo.

I tell to see before that they already considered these issues. The found out that it wouldn't work the Returnering-Skippy thinks without making the big problem somewhere else. They called it mond theory or some such a thing.

Put the silly looking pointy cap back on Skippy. I tell you yesterday there is a lot of things I don't know me, but I am not so stupid.

May 01, 2014
@ Benni-Skippy You don't see me here trying to talk about the science?

I got the silly looking pointy cap for you too if you want it you. Now you can get away yourself Cher, you have got my attention p'tit boug. Don't make me the misere you, I am not always so good nature me.

May 02, 2014
You guys comparing the size of your slide-rules again?
For communication, simple is best.
The Earth spins, ionosphere, can't see it but trust me it's there.
The sun spins, heliosheath, can't see it but if you trust Voyager 1 and 2 heliopause.
The SMBH spins, galactic current sheet theorized.
Earth's magnetic field extends in a distance relative to its mass. The sun same thing at 122Au,
that is one hundred twenty-two times greater than the Earth's distance from the sun.
The Milky Way's, (our) super massive black hole SMBH has an estimated mass 2 to 4 million solar masses. (maybe more but probably not less) How far do you think the galactic sheath extends? Should not it have already been interacting with Andromeda's throughout human history? What kind of space/time, gravitational lensing distortions could such interaction cause?
I've said it before, dark energy/matter are perfect analogies for our ignorance and propensity to act on nonsense.
Know now how to use your slide-rule?

May 02, 2014
The existence of dark matter has many things in common with (dismissal of) tired light model. The mainstream physicists have apparent problem with understanding of emergent phenomena, which are on the verge of particle and field concept (scalar waves). IMO both dark matter, both red shift are caused with density fluctuations of vacuum (space-time curvatures), which are relatively large but very short-living and subtle. Whereas both life-time both size of common particles is substantially smaller, than the wavelength of light, in which we are observing them. For deterministically thinking physicists these fuzzy artifacts are difficult to describe mathematically so that they tend to ignore them as a whole, despite their collective effects are quite pronounced. In analogy with water surface model of space-time it just means, the physicists ignore all waves and underwater turbulence, which cannot be described like the well defined deterministic ripples and solitons.

The Universe(U) after the Big Bang is governed by phase changes & symmetry breaking.

After the Dark Ages w/the appearance of atomic hydrogen(H), U reionized--why?

As U cooled, gravity pooled H, forming the galaxy-sized masses, largest to smallest and as cooling allowed progressively smaller masses to become gravitationally bound.

Compressing gas raises T, reconverted most of the H into ionized gas--not uniformly but at nucleation centers like supersaturated air nucleating on dust and pollen particles condensing into droplets forming clouds.

Ionization of H is endothermic, clamping T, allowing densification of plasma into spheres--'globules'. The largest collapsed into Pop III stars>>black holes>>central supermassive black holes.

Globules of pure H <100 stellar masses can't collapse into stars without additional mass, pressure or metallicity, so they persist in gravitationally-bound globules & cooled by evaporation to form the coldest objects in the U

Bok globules = dark matter

May 02, 2014
I got the silly looking pointy cap for you too if you want it you. Now you can get away yourself Cher, you have got my attention p'tit boug. Don't make me the misere you, I am not always so good nature me
I think bennis sentiments are best expressed in song.
http://youtu.be/IU03uD5PTG4

May 02, 2014
Bok globules = dark matter


How would such dense objects form? Why aren't they observed in the galaxy in great numbers? Why wouldn't galaxies much much brighter in the far infrared and submilimeter where globules emit? How would globules survive the densest regions of galaxies without merging or begin accreted? How would they survive cluster mergers? How could they explain cluster dynamics when the intracluster medium is millions of degrees, which couldn't support cool globules? How does that explain nucleosynthesis which does not agree that DM is baryonic? I'd say globules don't fit.

May 02, 2014
y = -GM/r + C


That's nothing but a fudge. If there was truly some constant like this why does the solar system follow Kepler's laws which have no constant? Why do earth satellites not need the constant?

You need to label your equation correctly. GM/r is the potential field, adding a constant to the potential field does nothing, only the gradient causes acceleration. Your equation is meaningless.

May 02, 2014
y = -GM/r + C


That's nothing but a fudge. If there was truly some constant like this why does the solar system follow Kepler's laws which have no constant? Why do earth satellites not need the constant?

You need to label your equation correctly. GM/r is the potential field, adding a constant to the potential field does nothing, only the gradient causes acceleration. Your equation is meaningless.


Thanks for that IMP-Skippy. I thought I was reading the google right where it said that thing Returnering-Skippy wrote didn't mean what he said it means.

May 02, 2014
@ Benni-Skippy You don't see me here trying to talk about the science?


............just my point, at least you get that part..........now try discussing with us Einstein's use of partial differential equations by which he proved in his General Theory of Relativity that the universe is of quasi-spherical geometry. Do think you can go there with me & your sharp "pointy" pencil?

May 02, 2014
.now try discussing with us Einstein's use of partial differential equations by which he proved in his General Theory of Relativity that the universe is of quasi-spherical geometry. Do think you can go there with me & your sharp "pointy" pencil?


@ Benni-Skippy I thought this one was about the dark matter disk. I never claim to be the scientist non, I am only the engineer man. Are you trying to say to me that you actually could understand what the Knave-Skippy was talking about? Was that what thing he was hinting at, the Relative quasi-spherical geometry? Or were you going off the topic with that trying to trick me?

May 02, 2014
.now try discussing with us Einstein's use of partial differential equations by which he proved in his General Theory of Relativity that the universe is of quasi-spherical geometry. Do think you can go there with me & your sharp "pointy" pencil?


@ Benni-Skippy I thought this one was about the dark matter disk. I never claim to be the scientist , I am only the engineer man. Are you trying to say to me that you actually could understand what the Knave-Skippy was talking about? Was that what thing he was hinting at, the Relative quasi-spherical geometry? Or were you going off the topic with that trying to trick me?


..........nope, partial differential equations are not a trick, they're the language of my job description as a Nuclear/Electrical Engineer. I'm just trying to do my part eliciting scientific thought in locating the Missing Dark Stuff that composes 90+ % of the Universe that Einstein's calculations predicted must exist to account for all that gravity.

May 02, 2014
..........nope, partial differential equations are not a trick, they're the language of my job description as a Nuclear/Electrical Engineer. I'm just trying to do my part eliciting scientific thought in locating the Missing Dark Stuff that composes 90+ % of the Universe that Einstein's calculations predicted must exist to account for all that gravity.


Well when you find it will cut ol Ira-Skippy in? After all the hooraheeing about the dark matters last the couple years, you going to make yourself a big bundle for finding it. Who ever find it first will probably get richer than Bill Gates.

May 02, 2014
@ P. S. for you Benni-Skippy I am the engineer man too me. On the towum / pushum boats, on the Mississippi and on the Ohio rivers. But we don't have the different equations for that, we just use the normal ciphering.

May 03, 2014
@ P. S. for you Benni-Skippy I am the engineer man too me. On the towum / pushum boats, on the Mississippi and on the Ohio rivers. But we don't have the different equations for that, we just use the normal ciphering.


You are a Phys.Org Moderator who does a very sloppy job of it. Your voting record has always given away how little you know about science, while demanding of others what you yourself are innately incapable of.

Your posting apps are simply a diversionary technique which only function to drive away those who want to discuss serious issues of science, once again you give this away with your voting record.

I have young children, and I know far better than you how derisive comments (usually unintended) affects how they respond to me in kind. Your voting record & linguistic apps as a Moderator reveal what you truly believe about Phys.Org being a competent science forum, the evidence is that you really don't care & Phys.org needs to replace you.

May 03, 2014
@ Benni-Skippy are you taking drugs or some thing? I been called the idiot and the troll and the moron and other things what I can't remember right now. But I have never been called the Moderator. My record for the voting don't give nothing away more than who I think are nice peoples and who I think are not so nice peoples. You cross peoples who you like you? You cross peoples who you don't like you? That should not be so hard for someone who wants to be nucleus engineer man to understand.

May 03, 2014
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May 04, 2014
This is a good postulation, what I think what we really need above all else is an accurate measurement of the Oort cloud including its temperature, but more importantly, its shape (including distance) and it's density.

Many objects in the solar system past the Kuiper belt have a higher orbital eccentricity, I suspect this pattern can be reflected outwards towards the rest of the solar system, including the Oort cloud. Not only is the density of the Oort cloud important for determining the chances of an impact are, an eccentric halo would be more gravitationally unstable as well, producing more impacts here on earth. The effect of this measurement could then be applied to the rate of major gravitationally disrupting events with in our local area (odds of stars getting close to each other, traveling through nebula, ect.) and on a galactic level as well, such as this dark matter hypothesis. This would give us a way to measure the mass of the dark matter disk as well.

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