Studying The Weight and Gravitational Behavior of Antimatter

Weighing Antimatter

Physicists at the University of California, Berkeley are studying the difference between matter and antimatter in relation to how it interacts with gravity.

Particles that have the same mass but with the opposite charge and quantum spin are called antimatter. Antimatter was predicted to exist in 1928 through equations by Paul Dirac. The next year, it was first observed by two physicists but considered it an anomaly and was not studied further.

Three years later, in 1932, Carl D. Anderson also observed the same thing in his experiments but instead of treating it as an error, studied it further. Bt using gamma rays, he created an anti-particle; a positively charged electron. Electrons are negatively charged and his discovery proved Dirac was right and antimatter does exist.

Anderson was awarded the Nobel Prize for Physics in 1936 for this discovery.

All particles has its antiparticle counterpart. The antiparticle of the electron is the positron. It carries a positive charge rather than a negative one. The proton's version is the anti-proton and it carries a positive charge. Despite the neutron having a neutral charge, there is an antineutron which is made up of antiquarks (the antiparticle of the quark).

What Is Antimatter?

Antimatter has been a popular concept in science fiction. But contrary to popular belief, antimatter has been observed and even created as early as 1932 and was theorized to exist years earlier.

What is Antimatter?

Antimatter are particles (antiparticles) that have the same mass as its counterpart but carry the opposite charge and quantum spin. Spin can be compared to how the Earth rotates on its axis while orbiting the Sun.

The antiparticle counter part of the electron is the positron. It carries a positive charge rather than a negative one. The proton's version is the anti-proton and it carries a positive charge.

There is also the antineutron despite the neutron having a neutral charge. This antineutron is made up of antiquarks (the antiparticle of the quark).

A Brief History of Antimatter

In 1929, two scientists in two different experiments observed a particle that exhibited a peculiar behavior. They saw what they believed to be an electron that travelled as if it had a positive charge. Electrons are negatively charged. The two physicists, Dmitri Skobeltsyn and Chung-Yao Chao, disregarded the anomaly and never pursued it afterwards.

Three years later, in 1932, Carl D. Anderson who was studying cosmic rays at the time noticed the same thing in his experiments. Believing this to be an electron but with a positive charge, he successfully created a positron by shooting gamma rays into other materials.

Anderson was awarded the Nobel Prize for Physics in 1936 for this discovery.

This validated Paul Dirac's theory from 1928 on the existence of positrons. At the time, he called them anti-electrons. It was Anderson who named them positrons; short for positive electrons.

The antiproton was discovered in 1955 by physicists Emilio Segrè and Owen Chamberlain while the antineutron by Bruce Cork in 1956.

New Method To Cool Down Antimatter Using Lasers Proposed

Researchers have proposed using lasers to cool down highly energetic anti-hydrogen atoms to better study its properties.

Antimatter is matter that carries an opposite charge and spin. An electron's antimatter counterpart is the positron. The electron is negatively charged while the positron is positively charged. The antimatter counterpart of a positively charged proton is a negative charge antiproton.

When antimatter collides with matter, they destroy each other and release energy in a process called annihilation. It must be noted that despite having opposite charges and quantum spin, both particles still carry positive energy.

In 1929, Dmitri Skobeltsyn and Chung-Yao Chao were the first to observe positrons in separate experiments. They noted that the observed particles behaved like electrons but curved in the opposite direction in an applied magnetic field. Neither scientists pursued the anomaly.

It was in 1932, that the positron was officially discovered by Carl D. Anderson, who also coined the term "positron". He was awarded the Nobel Prize for Physics in 1936 for the discovery.

In 1995, physicists at CERN for the first time produced nine anti-hydrogen atoms. This was done by combining one positron and one antiproton. This was followed up by Fermilab which produced 100 antihydrogen atoms.

The resulting antihydrogen atoms proved to be too energetic or "hot" for it to be observed and studied carefully. Subsequent experiments like CERN's Antiproton Decelerator in 1999 managed to lower its energy levels but was still difficult to study.

In 2005, CERN formed the ALPHA collaboration (Antihydrogen laser physics apparatus) whose primary goal is to create less energetic ("cold") antihydrogen atoms that are better suited to study