Antimatter in space?

[z-component]

I've read that in 1977, scientists approximated that there is a deposit of antimatter in the center of our galaxy. How could antimatter exist freely in space while coming into contact with matter? I know that once antimatter and matter come into contact, they are destroyed immediately while releasing a large amount of energy. Does anyone have an explanation for this?

Source: http://science.howstuffworks.com/antimatter1.htm

[Nereid]

Here (http://astro.estec.esa.nl/Integral/POMJan2004.html) is the best data to date (AFAIK - INTEGRAL SPI). Another link (http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=36082)

As to how positrons (the only anti-matter observed to date, other than anti-protons etc in cosmic rays) can exist without being annihilated ... if the space density of matter is low (say, < 10^3 electrons/cm^3), positrons can 'sit around' for a long time before they meet their nemises (electrons).

[z-component]

Thank you for the information! :smile: