Anti-Matter vs. Dark Matter

The Collison Annihlation of Matter and Anti-matter

The Collison Annihlation of Matter and Anti-matter

What is the difference between anti-matter and dark matter? Is there anything anti-matter and dark matter have in common?

Anti-matter is the idea of negative matter, or matter with the same mass but opposite an charge and quantum spin than that of normal matter. Anti-matter is just like normal matter with different properties. The antimatter of the electron (e-)  is the positron (e+); similarly, the antimatter of the proton is the anti-proton (p-). When normal matter and anti-matter collide, the two annihilate each other. Scientists speculate that anti-matter and matter existed in equal quantities in the early Universe.  The apparent asymmetry of high quantities of matter and very low quantities of anti-matter is a great unsolved problem in physics. Anti-matter is only found through radioactive decay, lightning, and cosmic rays (high-energy particles from supernovae) and very expensive to produce. Practical uses of anti-matter include the positron emission tomography (PET) used for medical imaging and as triggers to nuclear weapons.

Dark matter cannot be seen and is hard to detect, because dark matter interacts by gravity and weak atomic force, not with strong atomic forces (nuclear force: holds subatomic particles, electrons, neutrons, and protons, together in an atom) or electromagnetism. Dark matter constitutes about 22.7% of the Universe. On April 3, 2013, the International Space Station’s Alpha Magnetic Spectrometer (AMS) found the first evidence of dark matter. [AMS was carried out by the Endeavor in 2011 in one of NASA’s last space shuttle flights.] Normally, detectors are blocked by Earth’s atmosphere, but by orbiting Earth above its atmosphere,  the AMS can monitor cosmos rays (have an excess of anti-matter, discovered two decades ago) without hindrance. The AMS will tell scientists whether the abundance of positrons signal the presence of dark matter.  One theory scientists are testing is supersymmetry, which speculates that the collision and annihilation of two dark matter particles could produce positrons. Another instrument that could help the dark matter hunt is the Large Underground Xenon Experiment (LUX).

References

Anderson, Natali. “Antimatter Hunter aboard International Space Station Detects Hints of Dark Matter.” Sci-News.com. Sci-News.com, 4 Apr 2013. Web. 4 Apr 2013.

Boyle, Alan. “Space station’s antimatter detector finds its first evidence of dark matter.” NBCnews.com. NBC News, 3 Apr 2013. Web. 4 Apr 2013.

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