Matter and Antimatter

Matter is all the things around us. Matter has mass and occupies space. Matter is composed of atoms and molecules. All physical objects are composed of matter in the form of atoms. Atoms are composed of protons, neutrons and electrons. Mass of the atoms is concentrated in the nucleus of the atom. The nucleus of the atom houses protons and neutrons. The electrons revolve around the nucleus.

Protons carry positive charge and electrons carry negative charge. The number of positive charges, (number of protons) balances the negative charges, (number of electrons) making the atom electrically neutral. The neutrons are neither positive nor negative, therefore they are neutral particles.

Atoms are not capable of existing independently. They can only exist in combination of two or three atoms called molecules. Two to three molecules join together to form a compound. Protons, neutrons and electrons exist in different numbers in different atoms of different elements.

Matter exists in several states. The three common states are solid, liquid and gas. The fourth is the less familiar state called Plasma. The fifth state is the least known state called Bose-Einstein Condensate.

A molecule of water is formed when Hydrogen gas combines with oxygen gas. Hydrogen and Oxygen are in the gaseous state. Water, the product formed is in the liquid state. Water is totally a new substance formed and does not resemble any of the parent elements. This is called a chemical reaction.

A chemical reaction is a chemical change. A chemical reaction involves interactions between the electrons of the atom. A chemical reaction involve changing the position of electrons of the participating atoms and breaking the chemical bond existing between the atoms to form new chemical bond in the formation of the new compound. During a chemical reaction the nucleus of the atoms participating in the chemical reaction do not participate, that means nucleus remains unaffected.

Matter is converted into energy and in the recent times Einstein said that energy can be converted into matter.  Einstein proposed his famous formula in 1905 in his paper on Special theory of relativity. His famous formula is E= mc². According to his formula, mass (m) and energy (E) are interrelated. C is the speed of light. Atom bombs and nuclear reactors are the best examples that turn matter into energy.

The equation E = mc² states that the amount of energy possessed by an object is equal to its mass multiplied by the square of the speed of light. Since the speed of light is an incredibly high number, almost 300,000 km/sec, a small amount of mass contains a lot of energy. Additionally, the equation suggests that energy and mass are interchangeable with each other. In other words, energy can be converted to mass and mass to energy.

Formation of Helium atom by the fusion of two hydrogen atoms involves the nucleus

of the hydrogen atoms. This reaction is a similar to the reaction that is taking place 

in the sun.

Antimatter was first predicted in 1928 by English physicist Paul Dirac, soon after Big Bang. Antimatter is opposite of matter and is composed of antiparticles. The atomic and the sub-atomic particles of antimatter have properties opposite to the normal matter. The antiparticles have the same mass but are oppositely charged.

The antiparticle of electron is positron. Electron and positron have same mass but oppositely charged. That means electrons carry a unit negative charge but positron carry a unit positive charge.

The antiparticle of proton is antiproton. Protons are positively charged while antiprotons are negatively charged.

The antiparticle of neutrons is antineutrons. Both are equal in magnitude but opposite sign.  Both have same mass but both do not carry electric charge. Neutron has +1 Baryon number while antineutrons have -1 Baryon number.

A hydrogen atom has one proton in its nucleus. One electron is revolving round the nucleus. A hydrogen atom does not have a neutron in its nucleus. Positron and antiproton will bind together to form antihydrogen atom. The nucleus of antihydrogen atom does not have antineutron.

Antimatter is a material composed of antiparticles, that has the same mass as the particles of ordinary matter but with opposite charges as well as other particle with properties such as leptons, baryon numbers and quantum spin.

If a particle encounters its antiparticle both are converted into energy according to the formula E=mc² where m is the combined mass of particle and antiparticle. Scientists speculate that antimatter-powered spacecraft might be an efficient way to explore the universe. NASA has created a design for antimatter spacecraft.

The spacecraft is designed with the help of pellets of Deuterium and Tritium. Deuterium and Tritium are heavy Hydrogen. They are isotopes of Hydrogen with one or two neutrons in their nuclei. Hydrogen atom has no neutrons in their nucleus. An antiproton beam will strike the pellets of deuterium and tritium. This beam will also bash against the layer of uranium to create fission products that would spark a fusion reaction which will make the antimatter spacecraft move to explore the universe and other space missions.

The advantages of this matter – antimatter spacecraft are:

• The antimatter spacecraft will cut the fuel cost to a fraction.
• 100 percent of the mass of the matter and antimatter is converted into energy. When matter and antimatter collide, the energy released is 10 billion times greater than the energy released during hydrogen and oxygen combustion. 
• Matter-antimatter reactions are 1,000 times more powerful than the nuclear  fission produced in nuclear power plants and 300 times more powerful than nuclear fusion energy.

Research is required in creating and storing the released energy during the collision of matter and antimatter particles. Research is also required in devising proper engines for the spacecraft to withstand the enormous energy released during collision of matter and antimatter.