Image of the Cosmic Microwave Background radiation that stretches throughout our universe (Credit: European Space Agency)

In what might be the most monumentally important discovery in the last half century (yes, we're including the Higgs Boson in that), researchers have purportedly caught a glimpse of what might be dark matter—the elusive type of matter that makes up a quantifiable portion of the universe's mass. Dark matter is real; it's important; and we have absolutely no idea what it is, how it's created, or how it affects the universe at large. We do, however, know that unlocking its mysteries will help us understand the universe in a whole new, intimate light.

Quantum Weirdness on a Macroscale:

According to astronomers from the Leicester University, the discovery stems from work performed using the XMM-Newton telescope, which is hoisted in space. As it glanced at our local nuclear fusion reactor (the sun), it spotted the signature of axions traveling from the Sun's core toward Earth.

Axions, simply put, are hypothetical particles with negligible mass (we're talking less than an electron here) that have neither spin or charge. So how do they relate to dark matter? Theoretical predictions suggest that the particles do interact with two of the four fundamental forces: the strong and weak nuclear forces. Interacting with these two forces is a prerequisite for the elusive type of matter known as "dark matter."  This prerequisite exists because dark matter plays an integral role in holding galaxies together, but it can't be seen (it doesn't absorb or emit any light whatsoever) or directly quantified. As such, dark matter is similar to black holes in the fact that we can infer its existence based on its interactions with its surroundings, but that's about it.

Specifically, the axion is our answer to something called "cold dark matter," which is the type we've inferred based on our own astronomical observations.

Previous theories stated that axions have an the ability to partake in electromagnetic interactions regardless of the fact that they have no bonafide charge. Accordingly, if one were to meet any magnetic field (like the one surrounding Earth), the axion should be converted into something that can be detected conventionally — photons, which are generated within the Sun's core in abundance. However, up until this point, we've hit a wall when it comes to actually observing them.

Enter the ESA's XMM-Newton Observatory. It's genuinely the largest, most sophisticated X-Ray Observatory in operation, having been launched into space onboard the Ariane 5 rocket in December of 1999.  It has spent the past 15 years studying the x-ray emissions of our solar system, paying particular attention to the Sun. Over the years, it has acquired an extensive collection of data. Examining all of this data takes a lot of time. As such, scientists have been meticulously combing through it for some time. The results of their analysis were submitted to the scientific journal 'Monthly Notices of the Royal Astronomical Society' back in March (sadly, the person who spearheaded the research, George Fraser, passed away the following day).

What They Found:

Scrambling through every last bit of data, the researchers searched for observations in which the x-ray emissions exhibited untimely and unexpected seasonal modulations (changes). During such changes, we would see a significant flux in the amount of x-rays bombarding Earth's magnetic field (usually, the amount should remain the same at all times). It has been suggested (and apparently observationally confirmed) that the fluxes we observe in the x-rays coincide with an important dark matter prediction. Namely, that at a specific alignment, Earth should pass through a gargantuan halo of dark matter.

Researchers believed that the discrepancies in the seasonal modulations would stem from the conversion of axions into photons (which would happen, as previously mentioned, once the axions meet our planet's magnetic field and are transformed). Thus, if the seasonal modulations occur at a specific point, it should make it easier to recognize this perceived anomaly as something related to dark matter. "It is predicted that the X-ray signal due to axions will be greatest when looking through the sunward side of the magnetic field because this is where the field is strongest." And this prediction is exactly what happened. The team noted that the amount of x-rays increased by more then 10% when the measurements were gathered from this predicted vantage point.

Graphic of axions hitting magnetic field and being turned into x-rays. Image credit: (University of Leicester.)

As Andy Read, the co-author of the study notes: "We have discovered a seasonal signal in this X-ray background, which has no conventional explanation, but is consistent with the discovery of axions." In the research, the late George Fraser added, "It appears plausible that axions - dark matter particle candidates - are indeed produced in the core of the sun and do indeed convert to X-rays in the magnetic field of the Earth."

In conclusion, yes, we know that dark matter has become the new voyager (in refrence to 'the spacecraft that cried wolf,' and claimed to leave the solar system over and over again). It has come to the point that any announcements of the confirmation of dark matter should be taken with much skepticism. Moreover, as others have noted, a convincing discovery of dark matter will require consistent results from several different experiments using different detection methods. However, this research paper seems promising, and stands as a great beginning.

"These exciting discoveries, in George's final paper, could be truly ground breaking, potentially opening a window to new physics, and could have huge implications, not only for our understanding of the true X-ray sky, but also for identifying the dark matter that dominates the mass content of the cosmos," remarked Dr Andy Read, from the University of Leicester Department of Physics and Astronomy.

See the full press release here, or read the paper, "Potential solar axion signatures in X-ray observations with the XMM-Newton observatory," (released on October 20th) here.


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