Excess antielectrons aren’t from nearby dead stars, study says

ScienceNews.com ^ | November 16, 2017 | Emily Conover

[ETL]

The finding keeps open the possibility that the particles come from dark matter

New observations of the whirling cores of dead stars have deepened the mystery behind a glut of antimatter particles raining down on Earth from space.

The particles are antielectrons, also known as positrons, and could be a sign of dark matter — the exotic and unidentified culprit that makes up the bulk of the universe’s mass. But more mundane explanations are also plausible: Positrons might be spewed from nearby pulsars, the spinning remnants of exploded stars, for example. But researchers with the High-Altitude Water Cherenkov Observatory, or HAWC, now have called the pulsar hypothesis into question in a paper published in the Nov. 17 Science.

Although the new observations don’t directly support the dark matter explanation, “if you have a few alternatives and cast doubt on one of them, then the other becomes more likely," says HAWC scientist Jordan Goodman of the University of Maryland in College Park.

Earth is constantly bathed in cosmic rays, particles from space that include protons, atomic nuclei, electrons and positrons. Several experiments designed to detect the showers of spacefaring particles have found more high-energy positrons than expected (SN: 5/4/13, p. 14), and astrophysicists have debated the excess positrons’ source ever since. Dark matter particles annihilating one another could theoretically produce pairs of electrons and positrons, but so can other sources, such as pulsars.

It was uncertain, though, whether pulsars’ positrons would make it to Earth in numbers significant enough to explain the excess. HAWC researchers tested how positrons travel through space by measuring gamma rays, or high-energy light, from two nearby pulsars — Geminga and Monogem — around 900 light-years away. Those gamma rays are produced when energetic positrons and electrons slam into low-energy light particles, producing higher-energy radiation.

[ETL]

[Governor Dinwiddie]

[trebb]

So much we don't know and yet we try so hard to assert so many "truths/proofs" when it suits our political agendas.

I find much of this fascinating but it also tells me that our understanding of the universe is about as solid as an ant in a flower box, in a window in the Bronx, has of the world.

[ETL]

I find much of this fascinating but it also tells me that our understanding of the universe is about as solid as an ant in a flower box, in a window in the Bronx, has of the world.

I agree 100% and then-some, but couldn't help thinking about this opening scene from a classic cartoon...

[ETL]

Should not there be a "shower" of energy bursts when a positron and an electron merge? Assuming there is an attraction to do so...

Talk about "fatal attractions"!! (mutual annihilation!)

Sounds like some human relationships we hear about on the news.

[ETL]

I was born and raised on the Lower East Side of Manhattan myself: 1957 thru the end of 1970.

“Lola (or “Lolly” as Bugs calls her familiarly, also effecting her hoity-toity manner of speech) coaxes a biographical story out of Bugs, and he talks about growing up on the Lower East Side of Manhattan (presumably accounting for his accent).”

Bugs Bunny - A Hare Grows In Manhattan
https://www.youtube.com/watch?v=sGUVtBXCRtQ

[SunkenCiv]

Thanks ETL.

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[Ozark Tom]

β--fast electrons.

[samtheman]

Great post