Lightening Stroke Antimatter

Lightening keeps throwing up newphysics.  That these reactions are soapparent also suggests that we have a lot more room in terms of experimentalequipment than perhaps was thought.

There is a lot more going on thancan be modeled with simple electron flow which I think has been the obviousassumption.  Particles are also been tornapart and reassembled.  It has challengedus forever.

Anyway, this is our surprise forthe week that defied prediction.

Antimatter caught streaming from thunderstorms on Earth

By Jason PalmerScience and technology reporter, BBC News, Seattle

11 January 2011 Last updated at 03:34 ET

Electrons racing up electric field lines give rise to light, thenparticles, then light

A space telescope has accidentally spotted thunderstorms on Earthproducing beams of antimatter.

Such storms have long been known to give rise to fleeting sparks oflight called terrestrial gamma-ray flashes.

But results from the Fermi telescope show they also give out streams ofelectrons and their antimatter counterparts, positrons.

The surprise result was presented by researchers at the American Astronomical Society meeting inthe US.

It deepens a mystery about terrestrial gamma-ray flashes, or TGFs -sparks of light that are estimated to occur 500 times a day in thunderstorms onEarth. They are a complex interplay of light and matter whose origin is poorlyunderstood.

Thunderstorms are known to create tremendously high electric fields -evidenced by lightning strikes.

Electrons in storm regions are accelerated by the fields, reachingspeeds near that of light and emitting high-energy light rays - gamma rays - asthey are deflected by atoms and molecules they encounter.

These flashes are intense - for a thousandth of a second, they can produceas many charged particles from one flash as are passing through the entireEarth's atmosphere from all other processes.

Scaling down

The Fermi space telescope is designed to capture gamma rays from allcorners of the cosmos, and sports specific detectors for short bursts of gammarays that both distant objects and TGFs can produce.

 “Start Quote

I think this is one of the most exciting discoveries in the geosciencesin quite a long time”

Steven CummerDuke University

"One of the great things about the Gamma-ray Burst Monitor is thatit detects flashes of gamma rays all across the cosmic scale," explainedJulie McEnery, Fermi project scientist at Nasa.

"We see gamma-ray bursts, one of the most distant phenomena weknow about in the Universe, we see bursts from soft gamma-ray repeaters in ourgalaxy, flashes of gamma rays from solar flares, our solar neighbourhood - andnow we're also seeing gamma rays from thunderstorms right here on Earth,"she told BBC News.

Since Fermi launched in mid-2008, the Gamma-ray Burst Monitor (GBM) hasspotted 130 TGFs, picking up on the gamma rays in low Earth orbit as stormscame within its scope.

But within that gamma-ray data lies aneven more interesting result described at the meeting by Dr McEneryand her collaborators Michael Briggs of the University of Alabama Huntsvilleand Joseph Dwyer of the Florida Institute of Technology.

"We expected to see TGFs; they had been seen by the GBM'spredecessor," Dr McEnery explained.

"But what absolutely intrigues us is the discovery that TGFsproduce not just gamma rays but also produce positrons, the antimatterequivalent to electrons."
When gamma rays pass near the nuclei of atoms, they can turn theirenergy into two particles: an electron-positron pair.

Because electrons and positrons are charged, they align along theEarth's magnetic field lines and can travel vast distances, gathered intotightly focused beams of matter and antimatter heading in opposite directions.

Gamma rays (purple) can turn into focused matter/antimatter beams(yellow)

The dance of light and matter continues when positrons encounterelectrons again; they recombine and produce a flash of light of a precise andcharacteristic colour.

It is this colour of light, picked up by the Fermi's GBM, that is agiveaway that antimatter has been produced.

The magnetic field can transport the particles vast distances beforethis characteristic flash, and one of the Fermi detections was from a stormthat was happening completely beyond the horizon.

The results will be published in the journal Geophysical ResearchLetters.

Steven Cummer, an atmospheric electricity researcher from DukeUniversity in North Carolina, called the find "truly amazing".

"I think this is one of the most exciting discoveries in thegeosciences in quite a long time - the idea that any planet has thunderstormsthat can create antimatter and then launch it into space in narrow beams thatcan be detected by orbiting spacecraft to me sounds like something straight outof science fiction," he said.

"It has some very important implications for our understanding oflightning itself. We don't really understand a lot of the detail about howlightning works. It's a little bit premature to say what the implications ofthis are going to be going forward, but I'm very confident this is an importantpiece of the puzzle."

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