Antimatter belt around Earth discovered by Pamela craft

[ÑóẊîöʼn]

A thin band of antimatter particles called antiprotons enveloping the Earth has been spotted for the first time.

The find, described in Astrophysical Journal Letters (http://iopscience.iop.org/2041-8205/737/2/L29/), confirms theoretical work that predicted the Earth's magnetic field could trap antimatter.

The team says a small number of antiprotons lie between the Van Allen belts of trapped "normal" matter.

The researchers say there may be enough to implement a scheme using antimatter to fuel future spacecraft.

The antiprotons were spotted by the Pamela satellite (an acronym for Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) - launched in 2006 to study the nature of high-energy particles from the Sun and from beyond our Solar System - so-called cosmic rays.

These cosmic ray particles can slam into molecules that make up the Earth's atmosphere, creating showers of particles.

Many of the cosmic ray particles or these "daughter" particles they create are caught in the Van Allen belts, doughnut-shaped regions where the Earth's magnetic field traps them.

Among Pamela's goals was to specifically look for small numbers of antimatter particles among the far more abundant normal matter particles such as protons and the nuclei of helium atoms.

'Abundant source'

The new analysis, described in an online preprint (http://arxiv.org/abs/1107.4882), shows that when Pamela passes through a region called the South Atlantic Anomaly, it sees thousands of times more antiprotons than are expected to come from normal particle decays, or from elsewhere in the cosmos.
False colour bubble chamber image of antiproton/proton annihilation Antiprotons "annihiliate" if they come into contact with normal protons

The team says that this is evidence that bands of antiprotons, analogous to the Van Allen belts, hold the antiprotons in place - at least until they encounter the normal matter of the atmosphere, when they "annihiliate" in a flash of light.

The band is "the most abundant source of antiprotons near the Earth", said Alessandro Bruno of the University of Bari, a co-author of the work.

"Trapped antiprotons can be lost in the interactions with atmospheric constituents, especially at low altitudes where the annihilation becomes the main loss mechanism," he told BBC News.

"Above altitudes of several hundred kilometres, the loss rate is significantly lower, allowing a large supply of antiprotons to be produced."

Dr Bruno said that, aside from confirming theoretical work that had long predicted the existence of these antimatter bands, the particles could also prove to be a novel fuel source for future spacecraft - an idea explored in a report for Nasa's Institute for Advanced Concepts. (http://www.niac.usra.edu/files/studies/final_report/1071Bickford.pdf).

What's interesting is that this belt of antimatter is a renewable resource, being constantly replenished by infalling cosmic rays.

There have been designs proposed (http://www.engr.psu.edu/antimatter/Papers/ICAN.pdf) for spacecraft engines that utilise small numbers of antiprotons to generate thrust. Depending on the density of the the belt of antimatter, it may be possible to service an entire fleet of low-thrust but high-endurance spacecraft.

I also wish that more BBC science articles included links to the actual papers.

[ColonelCossack]

I think that, unless the density of the antimatter was quite low, we would have noticed something because whenever normal matter came into contact with it there would a huge amount of energy released :confused:

But then again, look at the asteroid belt. If you were to fly through that you probably wouldn't see a single asteroid, but in comparison to most other places it's teeming.

[Kiev Communard]

Now, if some anti-matter-powered counterpart to a space-based solar power station project (http://en.wikipedia.org/wiki/Space-based_solar_power)were developed, the situation with the energy crisis might be ameliorated a bit...

Besides, it is interesting to note that according to the paper posted by NoXion, the relatively regular Earth-to-Mars trips (with 120 days duration each, incuding 30 days delay for staying on the ground) will be possible, with a vehicle's speed of 120 km/s, which is much higher than anything that could be achieved under the present designs.

[ÑóẊîöʼn]

Now, if some anti-matter-powered counterpart to a space-based solar power station project (http://en.wikipedia.org/wiki/Space-based_solar_power)were developed, the situation with the energy crisis might be ameliorated a bit...

Building a solar power station would be technically easier, and since there's a lot more solar energy available, more sustainable - we could build as many solar power stations as we could, and the sun would still shine as strongly, but if we used the antimatter belt in such a fashion we would end up draining it at a greater rate than it is being replenished, rendering it useless.

[The Vegan Marxist]

I tend to find actual science websites to be far more sufficient than that of mainstream media websites with science sections:

http://www.newscientist.com/data/images/archive/2824/28245501.jpg

Antiproton ring found around Earth
by Hazel Muir
August 4, 2011

ANTIPROTONS appear to ring the Earth, confined by the planet's magnetic field lines. The antimatter, which may persist for minutes or hours before annihilating with normal matter, could in theory be used to fuel ultra-efficient rockets of the future.

Charged particles called cosmic rays constantly rain in from space, creating a spray of new particles - including antiparticles - when they collide with particles in the atmosphere. Many of these become trapped inside the Van Allen radiation belts (http://www.newscientist.com/article/dn14089-radio-waves-from-earth-clear-out-space-radiation-belt.html), two doughnut-shaped zones around the planet where charged particles spiral around the Earth's magnetic field lines.

Satellites had already discovered positrons - the antimatter partners of electrons - in the radiation belts. Now a spacecraft has detected antiprotons, which are nearly 2000 times as massive.

Heavier particles take wider paths when they spiral around the planet's magnetic lines, and weaker magnetic field lines also lead to wider spirals. So relatively heavy antiprotons travelling around the weak field lines in the outer radiation belt were expected to take loops so big they would quickly get pulled into the lower atmosphere, where they would annihilate with normal matter. The inner belt was thought to have fields strong enough to trap antiprotons, and indeed that is where they have been found.

Piergiorgio Picozza from the University of Rome Tor Vergata, Italy, and colleagues detected the antiprotons using PAMELA (http://pamela.roma2.infn.it/index.php), a cosmic-ray detector attached to a Russian Earth-observation satellite. The spacecraft flies through the Earth's inner radiation belt over the south Atlantic.

Between July 2006 and December 2008, PAMELA detected 28 antiprotons trapped in spiralling orbits around the magnetic field lines sprouting from the Earth's south pole (Astrophysical Journal Letters, DOI: 10.1088/2041-8205/737/2/l29 (http://iopscience.iop.org/2041-8205/737/2/L29/)). PAMELA samples only a small part of the inner radiation belt, but antiprotons are probably trapped throughout it. "We are talking about of billions of particles," says team member Francesco Cafagna from the University of Bari in Italy.

"I find it very interesting to note that the Earth's magnetic field works a little bit like the magnetic traps that we are using in the lab," says Rolf Landua (http://athena-positrons.web.cern.ch/ATHENA-positrons/wwwathena/landua.html) at the CERN particle physics laboratory near Geneva, Switzerland. There, researchers have been trying to trap (http://www.newscientist.com/article/dn16832-antimatter-mysteries-2-how-do-you-make-antimatter.html) antimatter (http://www.newscientist.com/article/mg20827874.500-antihydrogen-trapped-at-long-last.html) for ever longer periods (http://www.newscientist.com/article/dn20438-fleeting-antimatter-trapped-for-a-quarter-of-an-hour.html) to compare its behaviour with that of normal matter.

Alessandro Bruno, another team member from Bari, says antimatter in the Earth's radiation belts might one day be useful for fuelling spacecraft. Future rockets could be powered by the reaction between matter and antimatter, a reaction that produces energy even more efficiently than nuclear fusion in the sun's core.

"This is the most abundant source of antiprotons near the Earth," says Bruno. "Who knows, one day a spacecraft could launch then refuel in the inner radiation belt before travelling further."

Millions or billions of times as many antiprotons probably ring the giant planets.

http://www.newscientist.com/article/mg21128245.500-antiproton-ring-found-around-earth.html

[ÑóẊîöʼn]

I'm sorry, but new Scientist can go fuck themselves. Their standards of journalism are atrocious, and covers like the one below are prime examples:

http://i78.photobucket.com/albums/j99/NoXion604/NewScientistDarwinCover.jpg

Biologist PZ Myers has a scathing critique here (http://scienceblogs.com/pharyngula/2009/01/new_scientist_says_darwin_was.php):


Pity Roger Highfield, editor of New Scientist, which published an issue in which the cover was the large, bold declaration that "DARWIN WAS WRONG". He has been target by a number of big name scientists who have been hammering him in a small typhoon of outraged private correspondence (I've been part of it) that his cover was a misdirected and entirely inappropriate piece of sensationalism. We're already seeing that cover abused by creationists who see it as a tool — a reputable popular science journal has declared Darwin to be wrong, therefore, once again, science must be in retreat! — and I expect we're going to have to face the headache of many school board meetings where that cover is flaunted as evidence that students ought to be taught about how weak Darwinism is.

I think it was a mistake on New Scientist's part. They could have published a cover that announced "DARWIN IS DEAD!", which would be just as true and just as misleading, and would also bring nothing but joy to the ignorant. I don't think it would really help sell magazines, even; I suspect that most creationists are going to only use that cover to flog their cause, and never read any deeper than the widely available cover image.

I refuse to read a magazine that performs these kind of wrong-headed and sensationalist stunts to troll for sales.