How does it look when Earth is bombarded with dark matter?

December 7, 2017
Credit: University of Southern Denmark

University of Southern Denmark researchers have conducted simulations of dark matter particles hitting the Earth. Physicists believe that Earth collides with uncountable dark matter particles as it hurtles through space. Although no one has ever seen these mysterious particles, there is no question among physicists about their existence. Researchers have installed detectors around the globe in the hope of detecting them.

Dark matter particles can penetrate all other forms of matter, which means that they may even be able to traverse through Earth without losing any energy whatsoever. On the other hand, their impact with ordinary may hamper them slightly, resulting in a loss of energy.

"We just don't know, and that definitely doesn't make it any easier looking for them," said Timon Emken, a Ph.D. student at the Centre for Cosmology and Particle Physics Phenomenology (CP3) at the University of Southern Denmark. In order to learn more about how dark matter particles react with normal matter, Emken enlisted the aid of a supercomputer. The result was a program that can simulate the collision of dark matter particles with the Earth.

"Now, I can ask the computer to show me on the screen what happens when a hits Earth. For example, I can see on the screen which trajectory the particle would take from when it hits the surface of our planet until it leaves again," he explained.

The simulation is called DaMaSCUS, and it gives physicists the world over a new opportunity to test out various theories. The program is freely available, and the work that went into it has been published in the journal JCAP.

In the standard paradigm, dark matter particles transverse the Earth with a very low probability of interacting with atoms comprising the planet. However, underground detectors are tuned to do just that, i.e., to capture rare events of dark matter particle collisions with an atom inside a .

"But what if dark matter particles do not follow the standard paradigm? What if they actually interact strongly enough with ordinary atoms, that, as they cross the surface of the Earth and travel underground, they lose enough energy to become undetectable? In that case, we will never spot them using standard techniques," said Associate Professor Chris Kouvaris from CP3.

One of the things he is currently investigating is the possibility that dark matter particles scatter significantly as they transverse the Earth. Kouvaris and Emken used DaMaSCUS to demonstrate how such a scenario would play out. DaMaSCUS simulates billions of dark matter particles penetrating the Earth and scattering significantly with underground atoms, zig-zagging after every single collision.

"If this is the case, underground scatterings of dark matter particles with atoms might make the dark matter particles lose enough energy to be detectable in the underground detectors that we deploy today."

Associate Professor Chris Kouvaris explains his approach to detect dark matter. Credit: Anders Boe/SDU

Kouvaris' proposal is therefore to take a different approach to looking for the elusive particles. Today, there are a number of detectors situated around two kilometres below the Earth's surface. If dark matter interacts weakly with as neutrinos do, only these two particles can penetrate kilometres of the Earth's crust without being stopped. Thus, deep site detectors evade contamination of the signal from unwanted cosmic and terrestrial radiation and background noise.

However, according to Chris Kouvaris, if dark matter is light, it could actually interact strongly with ordinary atoms, losing energy on the way to the detector, and this can make deep site detectors unable to catch it.

"In that case, it would make more sense to search for dark matter signals using detectors on the Earth's surface," he said.

To overcome the problem of background noise, he suggests that instead of trying to distinguish dark matter from background noise, researchers should look for a daily varying signal in surface or low depth detectors.

Because the Earth is moving with respect to the center of the galaxy, dark matter hits the Earth predominantly from one direction. However, due to the rotation of the Earth around its own axis, dark matter that come from the direction of the dark matter wind travel different distances during the 24-hour period of a day.

The larger the distance travelled underground, the higher the probability of underground scattering. This is what creates the daily variation of the signal. The optimal location to exploit this effect is in the southern hemisphere at approximately 40 degrees latitude, i.e. in countries such as Argentina, Chile and New Zealand.

Using DaMaSCUS, Kouvaris and Emken can determine precisely the amplitude and phase of this daily varying signal, which could lead to the discovery of dark matter, if this scenario turns out to be true. Kouvaris is now collaborating with the DAMIC, which has a portable detector that could potentially be used to test Kouvaris' theories. In the new phase of DAMIC, the portable detector will weigh 1 kg. It is made of silicon manufactured by the Danish company, TOPSIL.

It is thought that 27 percent of the universe consists of dark . Scientists believe it binds galaxies together. However, no one really knows yet what is.

Explore further: Physicists suggest new way to detect dark matter

More information: Timon Emken et al. DaMaSCUS: the impact of underground scatterings on direct detection of light dark matter, Journal of Cosmology and Astroparticle Physics (2017). DOI: 10.1088/1475-7516/2017/10/031

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23 comments

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EyeNStein
3.5 / 5 (2) Dec 07, 2017
More importantly.
If there was significant dark matter in our neighbourhood how would it's mass affect the orbital period of the outer planets? And how much would the orbital periods decrease as dark matter is slingshot-ed by planets passing by.
We must know the orbital mechanics of the planets to enough decimal places by now, to give useful error bars on the calculation of surplus mass in our vicinity. To quantify the number of needles in our 40AU haystack.
Merrit
3 / 5 (3) Dec 07, 2017
I don't think the scientists really thought about the implications of DM being due some mysterious particle such as a wimp.

First of all, why would the DM be in a halo around the galaxy? If it only interacts weakly with ordinary matter or not at all besides gravity, then they should be bbeing pulled ever inwards.

Secondly, celestial bodies such as stars and planets should be capturing DM particles that happen to get nearby by the DM getting trapped inside the gravity wells.

This leads to the final conclusion that over time the DM would spread itself out over the ordinary matter in such a way that the ratios should be about equal of ordinary to DM for every celestial body which would bring us right back to where we were before we invented DM. You see our calculations for mass would already be including said DM.
Nik_2213
5 / 5 (2) Dec 07, 2017
Um, if 'Dark Matter' does not interact other than with gravity, then approaching particles will retain their 'escape velocity', scoot right through, out and away. You need a dissipative mechanism for capture...
RNP
5 / 5 (4) Dec 07, 2017
@Merrit
First of all, why would the DM be in a halo around the galaxy?

This is a misconception. The "halo" surrounds AND permeates the whole galaxy.

then they should be bbeing pulled ever inwards.

Yes. Just like the Earth is being pulled ever inwards by the Sun. However, just like the Sun, the DM particles lose no energy, so they continue in their "orbits".
Merrit
4.5 / 5 (2) Dec 07, 2017
@rip no doubt DM particles would be in orbits assuming the exist.

Whether or not they would be trapped in a gravity well depends on if they interact with each other. If they can collide and lose energy, then it would be possible especially how they would be more likely to collide inside the object.
Da Schneib
5 / 5 (1) Dec 07, 2017
The big challenge if this is correct will be background noise. They put the DM detectors deep in mines to avoid noise; but this hypothesis says we won't detect DM there because it's blocked right along with the noise.

A conundrum.
CubicAdjunct747
1 / 5 (5) Dec 07, 2017
what a waste of supercomputer time. It is calculating nothing. i can draw on a sheet of paper the same path of collision. A 6 month old could do the same with more accuracy than the supercomputer. How about i send these jokers this kind of drawing and let their Permanent Head Damage brains discuss the paths for hours and hours and write a paper on it. LOL
cantdrive85
3 / 5 (2) Dec 07, 2017
How does it look when Earth is bombarded with dark matter?

It looks just like this;
https://www.googl...MxSNU-8U

Then again it could look like this;
https://www.googl...mp;dpr=4

Nik_2213
not rated yet Dec 07, 2017
#CA : Difference is their algorithm may be published and reviewed...
Da Schneib
not rated yet Dec 07, 2017
@CA, this is about data; the simulations just show what we might see that we don't expect.

If we want data we need to be looking where we expect to find it since if we aren't looking we won't see it. I don't necessarily think this will give good results but at least we're not looking Up for a car coming South.
lupus
not rated yet Dec 07, 2017
Could it be that dark matter is not particulate at all ? I'm thinking how water can be ice, water or steam so maybe space itself has different phases. Maybe dark matter is an energetic state of space just as steam is an energetic state of water.
Seeker2
not rated yet Dec 08, 2017
First of all, why would the DM be in a halo around the galaxy?
This is a misconception. The "halo" surrounds AND permeates the whole galaxy.
then they should be bbeing pulled ever inwards.
Yes. Just like the Earth is being pulled ever inwards by the Sun. However, just like the Sun, the DM particles lose no energy, so they continue in their "orbits".
Not sure how a halo continues in its orbit though. Maybe as the galaxy continues in its orbit? I suppose galaxies do have orbits.
georgejmyersjr
5 / 5 (1) Dec 08, 2017
I was looking over at John Walker's fourmilab site, co-author of AutoCAD and other science, and noticed he has investigated a phenomena that shows background radiation has a diurnal emittance, I think the right word. Could it be part of the puzzle of dark matter? https://www.fourm.../cosmic/
tgmeloche
1 / 5 (1) Dec 08, 2017
Canadian Innovation

Continued belief in dark matter and the theory of general relativity is blunder in some academic circles which includes wasting public funding in mis-directed research The problem seems to be deep seated and perpetuated by self-interests within the academic community.

The solution is found in understanding how gravity works in the natural world. The rules nature follows with respect to gravitational force is best understood by how all atoms react to gravitational fluctuations. Until academics jump on the principles of atomic gravity their research in this controversial area will continue to flounder. Nature follows the principles of atomic gravity without question and so should academia.

The answer begins by understanding how and why gravity works. Nature follows the simple rules of atomic gravity. The principles are simple and have been proven in observations and experiments over and over again.

The principles of atomic gravity are in the google
milnik
not rated yet Dec 08, 2017
Gentlemen, be careful !!
You must understand and accept the structure of the universe.
The fact that science is invented with some "dark" substances, this is evidence that they have no knowledge of the structure of the universe.
This dark matter, which has nothing to do with it, is the Aether from which matter is formed, and the same with matter has "family" connections in the form of gravity and magnetism that form all phenomena in the universe.
milnik
not rated yet Dec 08, 2017
Apparently you did not understand what I wrote. When forming matter, quark gluon plasma is first formed, which are 3kg of the particle (3 quarks and 3 bonds of gluon) and free gluon, which occurs by annihilation of an electron-positron pair. Behind this process are formed of celestial bodies from which the chemical elements are formed up to the clusters of the galaxies. If something is not clear we can discuss this in detail, of course, if you have the knowledge and interest for that.
I do not care much about the works of some "scientists" who have a high level of science, because their deposition denies the basic existence of someone who has to manage all the happenings in the universe. People who do not believe in this and can not find out anything about it! 1.
Seeker2
not rated yet Dec 09, 2017
...forming matter,... occurs by annihilation of an electron-positron pair.
Did I get that right?
milnik
not rated yet Dec 09, 2017
Try to understand this intuitively, followed by clarifications that can be confirmed by the experiment.
Kron
not rated yet Dec 09, 2017
@milnik,
Please qualitatively define the term Aether. Aether is a name assigned to a particular type of medium, a medium that has been tested for and has been proven to be non-existent. You either don't understand how and why it's been proven to be non-existent (which I can attempt to explain to you in plain language) or you are incorrectly using the term for a type of medium you fabricated (or borrowed from elsewhere).

Explain what you mean by Aether.
Kron
not rated yet Dec 09, 2017
I could call dogs unicorns but this doesn't mean unicorns exist. If I define to you what a unicorn is you will be able to say: that's not a unicorn stupid, unicorns have horns, what you are describing is a dog!
milnik
not rated yet Dec 10, 2017
@Kron,
If you are doing science, do not enter the animal world and their names and prospects.
AETHER is the substance that fills the infinite universe and is rejected by scientists as not existing. But I think they have made an irreparable mistake both for science and for nature. Many scientists believed in the existence of this substance, but they could not discover it with experiments, and that's why Aether has something to do with them. Every human being has to know that everything in the universe has come about from something. This is something AETHER, which you ignore because you do not have the instruments to measure it. These instruments of science will never be able to form, because it is a substance managed by the Spiritual Entity of the Universe (SEU). I know that, like many others, you will say this is a religious view of science.
milnik
not rated yet Dec 10, 2017
But, remember, this has nothing to do with religion, because these are the laws of nature that human beings form us as the ultimate patent of nature. So why are you now clinging to your ignorance and understanding of yourself and your existence? Do you have dreams? Can you create instruments to measure and record? And why can not you? Because it is part and the law of the SEU, which science rejects and is therefore influenced by its inventions through models, formulas and false theories that have no bearing on natural laws. If one's awareness is at a higher level, this way of intuition (current link with the SEU) can find out the true causes of the phenomenon, and from the analysis of this phenomenon, it may be possible to check it and understand and measure it.
milnik
not rated yet Dec 10, 2017
Aether is what is in an "empty space", and science does not understand it.
Consider how scientists in particle collisions get some "new particles" that are larger and a couple hundred times that particle that drives "suicide" - wisdom.
You understand both scientists and scientists, that only occurs because in this "emptiness" there is AETHER.

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