Antimatter

:For the physics of antimatter, see the article on antiparticles.

Antimatter as fuel

In antimatter-matter collisions, the entire rest mass of the particles is converted to energy. The energy per unit mass is about 10 orders of magnitude greater than chemical energy, and about 2 orders of magnitude greater than nuclear energy that can be liberated today using chemical reactions or nuclear fission/fusion. The reaction of 1 kg of antimatter with 1 kg of matter would produce 1.8×1017 J (180 quadrillion Joules) of energy (by the equation E=mc²). In contrast, burning a kilogram of gasoline produces 4.2×107 J, and nuclear fusion of a kilogram of hydrogen would produce 2.6×1015 J.

Related Topics:
Mass - Energy - Energy per unit mass - Kg - J - E=mc² - Gasoline - Nuclear fusion

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Not all of that energy can be utilized by any realistic technology, because as much as 50% of energy produced in reactions between nucleons and antinucleons is carried away by neutrinos, so, for all intents and purposes, it can be considered lost. http://gltrs.grc.nasa.gov/reports/1996/TM-107030.pdf

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The scarcity of antimatter means that it is not readily available to be used as fuel, although it could be used in antimatter catalyzed nuclear pulse propulsion. Generating a single antiproton is immensely difficult and requires particle accelerators and vast amounts of energy—millions of times more than is released after it is annihilated with ordinary matter, due to inefficiencies in the process. Known methods of producing antimatter from energy also produce an equal amount of normal matter, so the theoretical limit is that half of the input energy is converted to antimatter. Counterbalancing this, when antimatter annihilates with ordinary matter energy equal to twice the mass of the antimatter is liberated—so energy storage in the form of antimatter could (in theory) be 100% efficient. Antimatter production is currently very limited, but has been growing at a nearly geometric rate since the discovery of the first antiproton in 1955http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/tyler_freeman/history.htm. The current antimatter production rate is between 1 and 10 nanograms per year, and this is expected to increase dramatically with new facilities at CERN and Fermilab. With current technology, it is considered possible to attain antimatter for $25 million per gram by optimizing the collision and collection parameters (given current electricity generation costs). Antimatter production costs, in mass production, are almost linearly tied in with electricity costs, so economical pure-antimatter thrust applications are unlikely to come online without the advent of such technologies as deuterium-deuterium fusion power. Several NASA Institute of Advanced Concepts-funded studies http://www.niac.usra.edu/studies/study.jsp?id=1071&cpnum=05-01&phase=I&last=Bickford&first=Jim&middle=&title=Extraction%20of%20antiparticles%20Concentrated%20in%20Planetary%20Magnetic%20Fields&organization=Draper%20Labratory&begin_date=2005-09-01%2000:00:00.0&end_date=2006-03-31%2000:00:00.0 are exploring whether the antimatter that occurs naturally in the Van Allen belts of Earth, and ultimately, the gas giants like Jupiter, might be able to be collected with magnetic scoops, at hopefully lower cost per gram.

Related Topics:
Antimatter catalyzed nuclear pulse propulsion - CERN - Fermilab - $ - Deuterium - NASA Institute of Advanced Concepts - Van Allen belt - Jupiter

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Since the energy density is vastly higher than these other forms, the thrust to weight equation used in antimatter rocketry and spacecraft would be very different. In fact, the energy in a few grams of antimatter is enough to transport an unmanned spacecraft to Mars in about a month—the Mars Global Surveyor took eleven months to reach Mars. It is hoped that antimatter could be used as fuel for interplanetary travel or possibly interstellar travel, but it is also feared that if humanity ever gets the capabilities to do so, there could be the construction of antimatter weapons.

Related Topics:
Antimatter rocket - Spacecraft - Mars - Mars Global Surveyor - Fuel - Interplanetary travel - Interstellar travel - Antimatter weapon

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