The EM force governs the electric and magnetic effects such as the repulsion between two similar electrical charges. It is long range, but weaker than the Strong force. It is either attractive or repulsive and acts as a mediating particle between pieces of matter carrying electric charge.

The weak force is responsible for radioactive decay and neutrino interactions. Short ranged and, as its name goes, it is very weak.

The gravitational force on the other hand is weak, but very long ranged. Furthermore, it is always attractive, and acts between any two pieces of matter in the Universe since mass is its source.

The four fundamental forces all play central roles in making the Universe what it is today, but with respect to the large-scale issues that are of interest to cosmology it is gravitation that is most important. This is because of two of its basic properties that set it apart from the other forces: (1) it is long ranged and thus can act over cosmological distances, and (2) it always supplies an attractive force between any two pieces of matter in the Universe.

Thus, although gravitation is extremely weak, it always wins over cosmological distances and therefore is the most important force for the understanding of the large-scale structure and evolution of the Universe.

6 leptons:

• electron, electron neutrino

• muon, muon neutrino

• tau, tau neutrino

6 quarks:

All but the proton, electron and neutrinos are unstable and decay to the stable particles. In the Standard Model the forces are communicated between particles by the exchange of quanta which behave like particles and these are the 4 intermediate vector bosons:

• gluon (nuclear force)

• photon (electromagnetic force)

• W and Z bosons (weak force)

Though still called a model, the Standard Model is a consistent and well-tested particle physics theory. Physicists use it to explain and calculate a vast variety of particle interactions and quantum phenomena. High-precision experiments have repeatedly verified subtle effects predicted by the Standard Model. However Standard Model is incomplete because it couldn’t predict a particle’s mass and gravity is not yet accounted.

One essential ingredient of the Standard Model, however, still eludes experimental verification - the Higgs field. It interacts with other particles to give them mass. The Higgs field gives rise to a new force carrier, called the Higgs boson, which has not been observed.

As the 21st century begins, physicists have developed a commanding knowledge of the particles and forces that characterize the ordinary matter around us. Simultaneously, astrophysical and cosmological space observations have revealed that this glimpse of the universe is incomplete— that 95 percent of the cosmos is not made of ordinary matter, but of a mysterious and enigmatic something else: “dark matter” and “dark energy”. We have learned that in fact we do not know what most of the universe is made of.

Understanding this unknown “new” universe requires the discovery of the particle physics that determines its fundamental nature. Powerful tools exist to bring the physics within reach. With astrophysical observations, we can explore the parameters of the universe; with accelerator experiments we can search for their quantum explanation. Energies at particle accelerators now approach the conditions in the first instants after the big bang, giving us the means to discover what dark matter and dark energy are—and creating a revolution in our understanding of particle physics and the universe.

After his very interesting lecture, ALP President James Kevin Ty invited ALPers to join  the September 18th free public Moon viewing to celebrate the 1st  International Observing the Moon Night (InOMN) that will be held at AstroCamp Observatory in SM Mall of Asia San Miguel by the Bay from 6:00pm to 9:00pm.  ALPers who have telescopes are encouraged to bring their telescopes to the site to share the Moon view to the public.  Members who doesn't have a telescope are also encourage to attend to help manpower tasks.