There’s a “dark matter hurricane” blowing through our corner of the Milky Way galaxy. Right this second, it’s passing over Earth. And this fast-moving stream could reveal major details about dark matter, a new study finds.
Published in Physical Review D, the study led by Ciaran O’Hare from the University of Zaragoza in Spain looked at a collection of nearby stars moving in the same direction known as the S1 stream. These are “believed to be the remnant[s] of a dwarf galaxy that was swallowed by the Milky Way billions of years ago,” a statement from APS Physics noted.
The European Space Agency’s billion-star survey using the Gaia spacecraft is reaching far out into our galaxy to discover and observe stars. And Gaia picked out the S1 stream because its some 30,000 stars have a different chemical composition than those native to our galaxy. And they’re traveling along a similar, elliptical path. About 30 such streams have been found in our galaxy, each the remnant of a previous collision.
Dark matter is an elusive material that scientists think, if the Standard Model is correct, exists in large quantities throughout space. Scientists still don’t know what dark matter actually is — there are a number of leading theories, but no one knows for sure. But the S1 stream is predicted to be blowing dark matter past us at about 310 miles per second (500 km/s) right this moment, and that could provide an opportunity for detection
“Current detectors looking for weakly interacting massive particles (WIMPs) – one widely discussed form of dark matter – probably won’t see any effect from S1,” the statement noted, “but future WIMP detectors might.”
It is believed that all galaxies are formed inside a large aura of dark matter, which we cannot see and does not interact with the external environment of normal matter.The researchers of this study said that about 10 million solar masses of dark matter came from the original dwarf galaxy and was traveling along the S1 stream.
“As the S1 stream ‘hits the Solar System slap in the face’, the authors write, its counter-rotating structure will dramatically increase the amount of dark matter appearing to come from the same patch of sky as the standard dark matter wind,” reports Cosmos Magazine.
“Indeed, it should produce a tell-tale ‘ring’-like structure around this wind, something that directional dark matter detectors… could easily detect in future.”
It might be probable to detect axions from the stream, which are ultralight particles that we cannot see, 500 million times lighter than an electron and could compose dark matter. They could also be converted to visible photons in the presence of a very strong magnetic field.
No direct detection of dark matter has ever been made, despite numerous efforts. But perhaps this “hurricane” will provide an intriguing opportunity to do so.
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