Anti-Matter Belt Discovered Around Earth 208
hydrofix writes "A thin band of antiprotons enveloping the Earth has been spotted for the first time. The find, described in Astrophysical Journal Letters [arXiv] (Note: abstract free, full text paywalled), confirms theoretical work that predicted the Earth's magnetic field could trap antimatter. The antiprotons were spotted by the Pamela satellite launched in 2006 to study the nature of high-energy particles from the Sun and cosmic rays. 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."
Fuel? No. (Score:5, Informative)
Not paywalled (Score:5, Informative)
Re:Not paywalled (Score:4, Informative)
There's no such thing as a paywall on arXiv -- you submit full preprints to it, and paywalling isn't an option. That is the point. :-)
Re:antimatter (Score:5, Informative)
They didn't find antimatter, they found anti-protons. Matter is what happens when particles arrange themselves a certain way. A few stray protons doesn't constitute matter: neither do some stray anti-protons.
Furthermore, they've found a whopping 28 of them in two years' research. Even if they'd found 28 atoms of anti-hydrogen (which would require that each anti-proton also have a positron), the amount is utterly irrelevant in terms of power generation. 28 atoms of anti-hydrogen (which I point out again that this is not) wouldn't produce a reaction capable of running a AA-battery flashlight.
I believe that the BBC has fallen victim to sensationalism and/or ignorance. It's pretty much what I've come to expect from the world press.
Thank you for trying to piss in their party, but the sensationalist/ignorant here is you.
Had you properly read TFA (or the original explanation) you would have found that
- You obviously don't know WTF is Pamela
- Pamela spent around 2% of its time in the South Atlantic Anomaly
- It detected 28 protons because that's within its capabilities (protip - particle detectors don't know an atom from an anti-atom BECAUSE IT'S NEUTRAL)
- "Protons doesn't constitute matter" What, they don't have mass? Protons fit squarely in the definition of matter, unless you are being sensationalistic or forgot the definition of matter.
And by the way, try to buy 28 antiprotons from CERN and see how much they ask for it
Fuel,well maybe... (Score:3, Informative)
hmm, 28 particles in three years, maybe not. That pretty much misrepresents the full article.
From section 4:
"The factor of proportionality between the antiproton flux and the number of detected antiproton
candidates, corrected for selection efficiencies and acquisition time, is by definition the gathering
power of the apparatus.
The apparatus gathering power was calculated to be significantly
reduced with respect to the geometric factor (http://pamela.roma2.infn.it/index.php?option=com_content&task=view&id=28&Itemid=256
The actual PAMELA instrument is fairly small(roughly 1.3 m x .5m) and has esentially no intake manifold.
From section 5:
During about 850 days of data acquisition (from 2006 July to 2008 December), 28 trapped
antiprotons were identified within the kinetic energy range 60–750 MeV. Events with geomagnetic
McIlwain coordinates (McIlwain 1961) in the range 1.1 L 1.3 and B 0.216 G were selected,
corresponding to the SAA. The fractional livetime spent by PAMELA in this region amounts to
the 1.7% ( 4.6 109 s).
My understanding is that that 850 days is time live for the instrument and 1.7% is percent of time in the SAA at geomagnetic ranges of interest. Right? So, 4.6X10^9 seconds works out to about 145 years. 1.7% of 850 days is 14.25 days. Quite a discreapency. Can someone else shed light?
So, you have an instrument with a very small physical intake and no collection system. Limited time at the target site as well. Given these factors, I would have to imagine that a larger more complex system could collect meaningful volumes. Might want to give that Buzzard ram scoop idea a second look.
The paper from Draper:
I like their estimations of collection rates. There should have been better treatment of power requirements vs. yeilds of the system. And, they at least could have given a nod to the Sci-Fi popularization of the same idea.
Now, lets wait too see some realistic propulsion system concepts.