Jagpal Singh August 2013 ~ All About Astronomy

Wednesday 21 August 2013

What are the smallest particles in the Universe?

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These smallest particles fall into several main categories, most notably fermions, hadrons and bosons.
For many years, the only known subatomic particles were protons, neutrons and electrons. By the 1960s, however, advancements in particle accelerator technology had shown evidence of hundreds of smaller constituent particles. By studying these particles -- all part of what is known in particle physics theory as the standard model -- physicists can try to explain all of the forces and matter existing in the universe.

These smallest particles fall into several main categories, most notably fermions, hadrons and bosons.


Fermions


Fermions are the building-block particles. There are two types of material fermions: quarks, which work to hold the nucleus of an atom together, and leptons, which do not. Fermions can be broken down even further: There are different types of quarks, and for each, an anti-quark. Quarks are found in groupings, but leptons are found alone. Electrons and neutrinos are examples of leptons. Fermions have a half-integer spi.

Hadrons


Hadrons are composite particles made of smaller particles. A proton, for example, is a hadron made from a combination of different quarks. Strong interactions bind the hadrons together and they always have charges, but no color. Protons and neutrons are the most stable hadrons. Hadrons come in two classes: baryons and mesons.

Quarks


Quarks are the fundamental constituents of hadrons and interact via the strong interaction. Quarks are the only known carriers of fractional charge, but because they combine in groups of three (baryons) or in groups of two with anti-quarks (mesons), only integer charge is observed in nature.

Leptons


Leptons do not interact via the strong interaction. Their respective antiparticles are the anti-leptons which are identical except for the fact that they carry the opposite electric charge and lepton number. The antiparticle of the electron is the anti-electron, which is nearly always called positron for historical reasons. There are six leptons in total; the three charged leptons are called electron-like leptons, while the neutral leptons are called neutrinos. Neutrinos are known to oscillate.

Bosons


Bosons are subatomic particles that carry force. They help particles interact with one another without touching, much like the forces of gravity or magnets. Unlike fermions, bosons have integer spin. The Higgs boson is believed to be the tiny particle that likely provides mass to all matter. Yet scientists aren't even sure that the Higgs boson exists.The Higgs boson remains one of the key questions remaining in physics and in wrapping up the Big Bang theory. If scientists can identify and study the particle that gives mass to all others, they can explain how the universe started from a seemingly invisible field.




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Monday 5 August 2013

Astronomy - August 2013 (40th Anniversary Issue)

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Astronomy - August 2013 (40th Anniversary Issue)

Look forward to studying the starry night sky? Revel in seeing if you can locate and connect the Big Dipper and the brightest North star? If you're a star gazing enthusiast, you'll love Astronomy. You'll learn more about exploring the universe in your own backyard with the most popular amateur astronomy magazine.

  • Astronomy - August 2013 (no ADS) 40th Anniversary Issue
  • English | PDF | 83 pages | 36.6 MB
FEATURES :-
  • 26 COVER STORY - 40 greatest astronomical discoveries
  • Astronomers' biggest breakthroughs have lifted the veil on our universe. RICHARD TALCOT T
  • 32 40 greatest mysteries of the universe
  • Astronomers know more about the universe than ever but still have much to learn. SARAH SCOLES
  • 38 Where will astronomy be in 40 years?
  • The future involves larger collaborations, computers, and telescopes. DEBRA MELOY ELMEGREEN AND BRUCE G. ELMEGREEN
  • 44 The Sky this Month
  • Neptune's summer surge. MARTIN RATCLIFFE AND ALISTER LING
  • 46 StarDome and Path of the Planets
  • RICHARD TALCOTT; ILLUSTRATIONS BY ROEN KELLY
  • 52 40 years of amateur astronomy
  • We live in our hobby's golden age - just look at what's happened in the past four decades. MICHAEL E. BAKICH
  • 58 Astronomy magazine's path to "stardom"
  • From its modest beginnings, the publication now leads the astronomy hobby as the most
  • popular magazine of its kind in the world. DAVID J. EICHER
  • 68 Ask Astro
  • Refracting light.
  • 70 40 deep-sky targets in Sagittarius
  • The Archer contains a dizzying variety of dazzling objects. MICHAEL E. BAKICH
  • 72 Hunt down summer's best dark nebulae
  • For a totally new observing experience, ignore the bright and aim for darkness. MICHAEL E. BAKICH
  • 76 A backyard imager advances science
  • An unexpected email opened the door for this astroimager. R. JAY GABANY
  • 80 Prime time for Neptune and Uranus
  • Late summer and early fall are the best times to track down the solar system's distant planets. RICHARD TALCOTT
COLUMNS :-
  • Strange Universe BOB BERMAN 11
  • Observing Basics GLENN CHAPLE 14
  • Secret Sky STEPHEN JAMES O'MEARA 18
  • Cosmic Imaging TONY HALLAS 24
QUANTUM GRAVITY :-
  • Snapshot 9
  • Breakthrough 10
  • Astro News 12
IN EVERY ISSUE :-
  • From the Editor 6
  • Letters 11, 18,24
  • New Products 84
  • Web Talk 84
  • Advertiser Index 87
  • Reader Gallery 88
  • Final Frontier 90
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