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Anti and Dark Matter
Name: Brian R. K.
Status: educator
Age: 20s
Location: N/A
Country: N/A
Date: 2001-2002
Question:
What is anti-matter/dark matter?
Replies:
Brian,
Anti-matter is material that, when joined with regular matter, will often
turn into pure energy. Our universe is made of many particles, but most of
what we see are protons, neutrons, and electrons. Anti-electrons (called
positrons) are fairly easy for laboratories such as Argonne to make. When a
positron meets with an electron, they can fuse into pure energy, becoming a
matched set of matter and anti-matter particles, or often just going off as
a photon of light. The energy produced is E=mc^2, where m is the total mass
converted into energy. As protons are so much more massive than electrons
(a ratio of about 2000), anti-protons are much more difficult to create.
Dark matter is not necessarily anti-matter. Dark matter is matter that for
some reason doesn't emit or reflect light (at least not enough light for us
to see). It could be purely transparent, never interacting with light. The
gravitational field is there. Something is behaving as if it has mass.
Still, for some reason we cannot see it. At a stellar distances, light is
the only tool we have. Nobody really knows what dark matter is, but new
theories are being developed on a regular basis.
Dr. Ken Mellendorf
Physics Instructor
Illinois Central College
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Update: June 2012
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