3.33 Sspd_chapter 1_part 13_ constituent particles of solid state  (Page 5/14)

Since only 3 decay modes and 3 lifetimes have been observed after investigating 4000 events it has been conclusively proved that there are only three generations of particles present in this Universe.

First generation consists of electron, neutrino and up- down quark. Second generation consists of mu electron or muon, mu neutrino and charm-strange quark. The third generation consists of tau lepton, tau neutrino and top-bottom quark.

The mass of electron-neutrino and mu-neutrino have been shown to be undetermined and zero respectively. Recently some new light has been shed on the rest mass and this is going to be crucial in determining the ultimate fate of the Universe.

On March 30, 2010, Large Hadron Collidor at CERN, Geneva, two oppositely rotating proton beams at 7 TeV were collided. Subsequently lead ion beam will be collided. This will help determine strong interaction and evolution of matter in early Universe. Precise measurement of CP violation and rare decays will be made. The hunt will begin for dark matter which is abundant in present day Universe. Some of the major puzzles of Modern Physics will be addressed like the origin of matter in hadron and the grand unification of forces. Standard Model will be rediscovered . This will be the necessary precursor to looking for New Physics.

Our galaxy known as Milky Way belongs to a cluster of galaxies known as Local Group. Belonging to the same Local Group is another galaxy known as Large Magellenic Cloud (LMC). In this galaxy on 23 ^rd February 1987 there was a supernova explosion in a star named 1987A. This supernova explosion was discovered by Ian Shelton who was a technician but after this discovery was admitted into Graduate School.

A main sequence star lighter than 1.44 Solar Mass (ChandraShekhar Limit) after completing its life span explodes into Nova Explosion and expands into Red Giant and finally contracts into a White Dwarf.

A star heavier than 1.44 Solar Mass and lighter than 3 Solar Mass explodes into Super-Nova Explosion and the star contracts into a Neutron Star. The neutron star has a magnetic dipole . This magnetic dipole axis is inclined to the geographical polar axis and this leads to synchrotron radiation which makes the neutron star a pulsar.

A star heavier than 3 Solar Mass also explodes into Super-nova explosion but the star collapses into Black Hole.

After 1987A event scientists got an opportunity to study neutrino and mu-neutrino extensively and it has been decisively established that they have a finite mass .

This mass tells that our Universe is flat Universe and it has zero curvature. An open Universe will go on expanding up to eternity and ultimately all celestial objects will become cold and radiationless.

From Newtonian Mechanics we know that the escape velocity is given by the following equation:

V escape = √(2GM/R)…………………………………. 1.114

Where G = Gravitational Constant;

M = mass of the body under consideration;

R = radius of the body under consideration.

Hubble and Humason had established that all the galaxies are racing away from one another and the velocity of recession is directly proportional to the distance of the galaxy from our Earth: