Antimatter by Jeff Harm Fall 2012

This page is about antimatter - matter composed of particles with the same mass but a charge and quantum spin opposite to that of normal matter. The antimatter equivalent of the proton is the anti-proton, and the antimatter equivalent of the electron is the positron. Protons have a positive charge, so anti-protons have a negative charge. Electrons have a negative charge, so positrons have a positive charge. Antimatter particles bind to form matter in the same way that normal particles do. Just like particles may bind to form a hydrogen molecule, antiparticles may bind to form an anti-hydrogen molecule. When matter and antimatter collide, they are both annihilated and release all or most of their mass as energy. The universe is thought to have begun with equal amounts of matter and antimatter, but today only a small percentage of the observable universe is composed of antimatter. The reasons for this asymmetry are currently unknown.



NASA

NASA's Fermi Telescope Detects Antimatter Creation In Thunderstorms

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Author: NASA
Last Updated: January 10, 2011
Date Reviewed: November 29, 2012
Reviewed By: Jeff Harm
Accuracy: Information comes straight from observations made by NASA's Fermi Space Telescope.
Readability and Clarity: This page is written for the general public.
Ease of Navigation: There is a link to all other news related to NASA's Fermi Space Telescope on the page, as well as links to news about other NASA missions.


LiveScience

Electron Antineutrinos Observed Changing Form

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Author: Clara Moskowitz
Last Updated: March 8, 2012
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Accuracy: Accurately describes neutrinos and their antimatter counterparts, as well as the way they "oscillate" from one form to another.
Readability and Clarity: This page is written for the general public.
Ease of Navigation: There are nifty links throughout that can give you more information on antimatter and on neutrinos. They are links to more articles on LiveScience.

ScienceMag

Antimatter Decay Rate Found To Differ From That Of Normal Matter

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Author: Jon Cartwright
Last Updated: February 29, 2012
Date Reviewed: December 1, 2012
Reviewed By: Jeff Harm
Accuracy: Information is up-to-date, covering recent experimental results from CDF (the Collider Detector at Fermilab).
Readability and Clarity: This page is written for the general public.
Ease of Navigation: There is a link in the article to previous experimental results on antimatter's decay rate. There is also a link on the left side of the page to all other astronomy-related articles on the website.

GizMag

Beamed Core Antimatter Propulsion

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Author: Brian Dodson
Last Updated: June 12, 2012
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Accuracy: Mixed. There is both accurate information on our current understanding of antimatter and some more theoretical things about how we might be able to harness antimatter's energy for use in spaceship propulsion.
Readability and Clarity: This page is written for the general public.
Ease of Navigation: There are no links in the article to find out more information about the topic. There is a link in the right side of the page for more Science and Education articles.

Science Daily

Majorana: A Particle That Is Its Own Antiparticle

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Author: Science Daily
Last Updated: April 13, 2012
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Accuracy: Contains recent information on the "Majorana" fermion, a fundamental particle related to antimatter that scientists are still working to understand.
Readability and Clarity: This page is relatively challenging to fully understand - some cutting-edge electronics and physics concepts here.
Ease of Navigation: No links in the article to find out more about the topic. Near the top of the page you can click "Space & Time" to find out more about astronomy and physics topics like antimatter.

Lawrence Berkeley National Lab

Basics of Antimatter

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Author: Lawrence Berkeley National Lab
Last Updated: November 18, 2004
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Accuracy: Mostly accurate information on the basics of antimatter. Incorrectly states that antimatter has the same quantum spin as normal matter.
Readability and Clarity: This page is written for the general public.
Ease of Navigation: Clicking the "Home" link on the bottom of the page will allow you to find out much more about various physics topics, but not much about antimatter.

National Geographic

Antimatter Atoms Trapped for First Time

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A detail of the trap used to combine positrons and antiprotons to create antimatter atoms.

Author: Ker Than
Last Updated: November 18, 2010
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Readability and Clarity: This page is written for the general public.
Ease of Navigation: Several links in the article will show you more information about antimatter, physics and scientific organizations.

Scientific American

Scientists Discover Possible Difference Between Matter and Antimatter

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MATTER AND ANTIMATTER annihilate each other on contact. Experiments hint at a subtle difference between them that may explain why antimatter is so rare. Image: iStockPhoto

Author: JR Minkel
Last Updated: April 3, 2008
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Readability and Clarity: This page is written for the general public.
Ease of Navigation: Various external links are provided in the article on the topics of antimatter and physics.

How Stuff Works

How Antimatter Spaceships Could Work

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Photo courtesy of NASA

Author: Kevin Bonsor
Last Updated: Date Unknown
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Readability and Clarity: This page is written for the general public.
Ease of Navigation: This article provides a lot of links to other pages on HowStuffWorks that explain how various real and fictional propulsion technologies function, as well as links to other physics topics.

Phys.org

Generating Matter and Antimatter

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Anti-Matter as depicted in Dan Browns Angels and Demons

























Author: Phys.org
Last Updated: December 8, 2010
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Readability and Clarity: This page is written for the general public.
Ease of Navigation: Links in the article will search for other articles on Phys.org related to antimatter, electron beams, neutron stars, and other physics topics.

LiveScience

Physicists Accurately Weigh Antimatter

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Photo prvoded by CERN

Author: Jeanna Bryner
Last Updated: July 28, 2011
Date Reviewed: December 9, 2012
Reviewed By: Jeff Harm
Readability and Clarity: This page is written for the general public.
Ease of Navigation: Links in this article lead you to more LiveScience articles on antimatter, the big bang, and other physics topics.