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Scientists Eye Dark Matter in Mystery of Anti-Matter on Earth

Recent research findings suggest positrons from pulsars not the cause.

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There is now a prime suspect in one of the biggest mysteries in the world of astronomy.

Since scientists discovered in 2008 that the Earth is bombarded with three times as much antimatter — the equal, but oppositely charged counterpart to all normal matter in the universe — as originally believed, there has been a scramble to find the original source, Scientific American reports.

When a particle, say a negatively charged electron, collides with its antimatter version, a positron, both are destroyed, releasing gamma rays in the process.

At first, researchers zeroed in on pulsars, a rotating neutron star or white dwarf stars that spill out electromagnetic radiation as they spin. To observe the effects from two relatively nearby pulsars, international team used the High-Altitude Water Cherenkov gamma-ray observatory, perched on a volcano in Mexico to analyze reactions when the bombarding positrons hit the water held in 300 corrugated steel tanks at the facility.

The results, published in the Nov. 17 issue of Science, has now cast doubt that enough positrons could escape the “fog” surrounding positrons to reach Earth. “Now they are closing in on this strange bombardment’s source, tentatively linking it with the enigmatic dark matter thought to make up roughly five-sixths of all matter in the universe,” writes Scientific American.

The problem is dark matter is much harder to detect since it is theoretically invisible except for minute gravitational effects on regular matter.

“The only one left standing seems to be dark matter,” study co-author Jordan Goodman told Scientific American, who added that there is still more work to be done to confirm that reasoning.

“We’re just saying that we’ve given an alibi to the other major suspects, the pulsars.”

Read full story at Scientific American