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Thursday 1 September 2011

Antimatter

Antimatter is a term in particle physics. It is a form of matter in which all the attributes of an ordinary atomic particle are reversed such as the electron and its antimatter equivalent, the positron.  

Carl David Anderson proved the existence of antimatter at the California Institute of Technology in 1932, when he discovered the positron.

Below is a cloud chamber photograph of the first positron ever observed. The thick horizontal line is a lead plate. The positron entered the cloud chamber in the lower left, was slowed down by the lead plane, and curved to the upper left. 


In 1996 physicists using the particle accelerator at CERN in Geneva, Switzerland, created the first atoms of antimatter: nine atoms of antihydrogen survived for 40 nanoseconds (40 billionths of a second).

If all the antimatter ever made by humans were annihilated at once, the energy produced wouldn’t even be enough to boil a cup of tea.

There is strong evidence that the observable universe is composed almost entirely of ordinary matter, and hardly any antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics.


One way that scientists are trying to solve the antimatter-matter asymmetry problem is by looking for antimatter left over from the big bang. The Alpha Magnetic Spectrometer is a particle detector that was flown on the space shuttle Discovery in June 1998, It now sits atop the International Space Station searching for these particles.

In August 2011 scientists analyzing data from the satellite PAMELA confirmed that a plasma belt surrounding Earth contains antimatter. 

Bananas produce antimatter, releasing one positron about every 75 minutes. This occurs because bananas contain a small amount of potassium-40, a naturally occurring isotope of potassium. As potassium-40 decays, it occasionally spits out a positron in the process.

Because antimatter can make so much energy, it can be used for a lot of things, such as fuel for going into outer space, or in our cars. The problem is that antimatter is very expensive to make, and is almost as expensive to store, since it cannot touch regular matter. One Gram of Antimatter costs approximately 62 trillion dollars.


Sources Hutchinson Encyclopedia © RM 2011, Symmetry magazine


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