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Composition
The particles studied in cosmic and heliospheric science are atoms or pieces of atoms. Atoms are composed of three major building blocks: protons (with a positive charge), neutrons (with no charge), and electrons (with a negative charge). The nucleus of an atom contains the protons and neutrons, while the electrons orbit the nucleus. The number of protons determines to which element the atom belongs: hydrogen has one proton, carbon has six, etc.
The Particle Adventure (by the Particle Data Group) introduces the theory of fundamental particles and forces, called the Standard Model. It explores the experimental evidence and the reasons physicists want to go beyond this theory. In addition, it provides information on particle decay and a brief history section.
The Science of Matter, Space, and Time (by the Fermilab) contains another good particle physics "tour".
![Hydrogen, deuterium, and tritium models](hdt.gif)
New elements are created in stars by a process called nucleosynthesis. (More about nucleosynthesis...)
The number of neutrons tells us which isotope of the element is present. The isotope number is the total of the number of protons plus the neutrons. Take carbon, for example, which is a very common element necessary for life, and is found in nature as diamonds and graphite. We find several different isotopes of carbon in nature. Carbon-12 has an equal number of protons and neutrons, six of each. Carbon-14 contains two more neutrons (eight) than carbon-12, but still has only six protons. This makes carbon-14 an isotope of carbon, but it is different from carbon-12. While carbon-12 is a stable isotope, carbon-14 is unstable, or radioactive. It is much less common in nature but is found where carbon-12 is found. Because of its radioactive nature, carbon-14 is used to date archaeological artifacts.
Shown in this figure, deuterium and tritium are isotopes of hydrogen.
This image is from the Princeton
Plasma Physics Laboratory, which also offers a good interactive tour of matter.
The periodic table of the elements provides some information about each of the different elements. Each element has distinctive properties, and those with similar properties are grouped into families, shown by the different colors. Follow the link on the periodic table here to learn more about it and the different elements.
In an atom, the number of electrons that orbit the nucleus equals the number of protons in the nucleus, thus making an atom electrically neutral. When bombarded by ultraviolet (UV) radiation or after being struck by energetic particles, atoms can lose one or more of their electrons. The positively charged remains of these atoms are called ions. The number of electrons lost determines the charge state of the particle. For example, alpha particles are helium nuclei with a double positive charge; they have two protons and two neutrons, but no electrons.
Together with their freed electrons, the ions form a plasma. Plasma is a fourth state of matter, not a liquid, solid, or gas. Matter in the Sun is in a plasma state. Plasma is the most common state of matter in the Universe. More than 99% of all matter is plasma, so what we see on Earth is the exception. Since plasmas consist of electrically-charged particles, electric and magnetic forces affect a plasma.
When we measure the elemental, isotopic, and charge composition of ions, it helps us to understand how nature selected the particles and accelerated them to the energies at which we find them. The "composition" of electrons is not interesting, since all electrons look the same. But their number, energy, and direction of travel are important.
Back to Basics
August 26, 2008: XMM-Newton's
massive discovery -- Astronomy.com
August 23, 2008: The matter of
the Bullet Cluster -- APOD
August 22, 2008: Some
solar flares may be caused by dark matter -- New Scientist
August 19, 2008: Chemist
travels world to study mysterious properties of neutrinos --
Brookhaven National Lab
August 13, 2008: NGC 6888: The
Crescent Nebula -- APOD
August 13, 2008: Physicists
await dark matter confirmation -- NAture
August 6, 2008: Jupiter
and Saturn full of liquid metal helium -- UC Berkeley
July 25, 2008: Tracking
down origin of matter and antimatter -- Science Daily
July 18, 2008: A super mix inside neutron
stars -- Physical Review Focus
July 16, 2008: Where
balloons have made advances -- Nature
July 14, 2008: Particles
retain weight for billions of years -- Space.com
July 10, 2008: R&D
100 Award for new UM-NIST neutron detector -- University of
Maryland
July 9, 2008: Physicists
discover new particle: The bottom-most "Bottomonium" -- SLAC
July 5, 2008: First
underwater neutrino telescope has been constructed -- Science
Daily
June 26, 2008: Dark
matter is denser in the solar system -- Universe Today
June 24, 2008: 'Frozen'
stars could shed light on dark matter -- New Scientist
June 4, 2008: Physicists
to target neutrinos -- Nature
June 3, 2008: Super-luminous
supernovae -- Astronomy.com
June 3, 2008: Protons
pair up with neutrons -- Brookhaven National Laboratory
May 29, 2008: Astronomers
map the metals in millions of Milky Way stars -- Sloan Digital Sky
Survey
May 29, 2008: New form of
artificial radioactivity -- AIP
May 21, 2008: The many versus the one
-- Physical Review Focus
May 21, 2008: Looking for ET's
neutrino beam -- Physics World
May 20, 2008: Atomic
neutrality -- CERN
May 20, 2008: Hubble
Space Telescope survey finds missing matter, probes intergalactic
web -- University of Colorado
May 20, 2008: Willis Lamb:
1913-2008 -- Physics World
May 15, 2008: Can
one 'pin down' electrons? -- Eurekalert
May 9, 2008: Designer
isotopes push the frontier of science -- NSF
May 7, 2008: XMM-Newton
discovers part of the missing matter in the universe -- Astronomy
& Astrophysics
May 1, 2008: The
heaviest element yet? -- Nature
April 30, 2008: Plasma
physics: From black holes to radio reception -- Scientific
American
April 29, 2008: High-flying
electrons may provide new test of quantum theory -- NIST
April 27, 2008: The Galactic
Center Radio Arc -- APOD
April 24, 2008: Exotic
quantum state of matter discovered -- Science Daily
April 21, 2008: The
range of annihilation -- HEAPOW
April 21, 2008: Quarter
electrons may enable exotic quantum computer -- Scientific
American
April 16, 2008: Particle physics
proves that arsenic didn't kill Napoleon -- CERN
April 10, 2008: Optical clocks get
better -- AIP
April 9, 2008: Higgs
boson: A ghost in the machine -- Time
April 9, 2008: Newly
discovered fundamental state of matter, a superinsulator, has been
created -- Science Daily
April 8, 2008: 'God
particle' expected to be found soon -- Time
April 8, 2008: 14-year-old
CEO makes chemistry a game with 'Elementeo' -- Eurekalert
April 7, 2008: Periodic
table: Nuclear scientists eye future landfall on a second 'island of
stability' -- Science Daily
April 3, 2008: Matter-antimatter
split hints at physics breakdown -- Scientific American
April 2, 2008: Bon
MOT: Innovative atom trap catches highly magnetic atoms --
Eurekalert
April 1, 2008: Compressed
stars: Physicists compress unstable nucleus of nickel 56 for first
time -- Science Daily
March 30, 2008: Weak lensing
distorts the universe -- APOD
March 28, 2008: Why matter
matters in the universe -- University of Melbourne
March 25, 2008: Atom cloaking
-- AIP
March 24, 2008: Physicists
show electrons can travel more than 100 times faster in graphene
-- University of Maryland
March 19, 2008: Japanese
particle accelerator hints at 'new physics' -- New Scientist
March 15, 2008: Crashed
probe yields sun secrets -- BBC
March 6, 2008: Controlling
most atoms now possible -- Eurekalert
March 3, 2008: Particle
collider's last big piece set -- National Geographic
February 27, 2008: US
experiment takes the lead in the competitive race to find dark
matter -- Caltech
February 25, 2008: Dawn of the
Large Hadron Collider -- APOD
February 25, 2008: Electron
gets film debut in first-ever video of its kind -- Science Daily
February 1, 2008: Dark
fluid: Dark matter and dark energy may be two faces of the same
coin -- Science Daily
January 31, 2008: New
discovery on magnetic reconnection to impact future space missions
-- Science Daily
January 29, 2008: Nowhere
to hide: New ultra-powerful microscope probes atomic world --
Science Daily
January 23, 2008: A new calculation
explains the mechanics behind carbon dating -- AIP
January 22, 2008: Milky
Way's antimatter linked to exotic black holes -- New Scientist
January 22, 2008: Future
of top U.S. particle physics lab in jeopardy -- Scientific
American
January 22, 2008: CERN:
Celebrating the lowering of the final detector element for Large
Hadron Collider -- Science Daily
January 17, 2008: The
future of physics -- Scientific American
January 17, 2008: Large Hadron Collider: The discovery machine -- Scientific American
January 17, 2008: The
coming revolutions in particle physics -- Scientific American
January 9, 2008: Integral
discovers the galaxy's antimatter cloud is lopsided -- ESA
January 9, 2008: Vast
cloud of antimatter traced to binary stars -- NASA GSFC
January 9, 2008: Japanese
particle physics in good health -- Physics World
January 2, 2008: Large
Hadron Collider at CERN expected to go live summer of 2008 --
Science Daily
January 1, 2008: Helium
supplies endangered threatening science and technology --
Washington University in St. Louis
December 22, 2007: The
best of 2007 -- Physics World
December 21, 2007: The size of the
helium-8 nucleus has been measured -- AIP
December 21, 2007: Transparent nuclei --
Physical Review Focus
December 19, 2007: US
budget cuts a 'body blow' to particle accelerator -- New Scientist
December 13, 2007: Ten top physics
stories for 2007 -- AIP
December 10, 2007: Major
physics breakthrough in understanding supersolidity -- Science
Daily
November 30, 2007: First
estimate of size of new atomic particle (from 1937) -- Science
News
November 30, 2007: Galaxies
are born of violence between dark matter and interstellar gas --
Science Daily
November 28, 2007: Einstein's
biggest blunder? Dark Energy may be consistent with cosmological
constant -- Science Daily
November 20, 2007: Nuggets of new physics
-- APS
November 17, 2007: Young's
experiment performed in a hydrogen molecule -- Science Daily
November 15, 2007: Physicists
peer closely at radioactive decay of a rare isotope at the edge of
nuclear existence -- Science Daily
October 25, 2007: Newly
created forms of magnesium and aluminum -- NSF
October 9, 2007: How
can graphite and diamond be so different if they are both composed of
pure carbon? -- Scientific American
October 5, 2007: Shining
a light on mysterious 'dark matter' -- Science Daily
September 13, 2007: Matter
or antimatter? Why not both? -- Australian Broadcasting Company
July 23, 2007: Ruling
unruly substances -- Staying out of jams -- Science Daily
June 6, 2007: Researchers
catch motion of a single electron on video -- Eurekalert
November 22, 2006: Genesis findings solve Apollo lunar soil mystery -- MoonDaily
August 21, 2006: Heavy hydrogen clumps in space -- Australian Broadcasting Company
April 6, 2006: It's the Sun, but not as we know it -- Australian Broadcasting Corporation News
November 15, 2005: Cosmochemist to receive National Medal of Science -- EurekAlert!
February 27, 2005: The solar spectrum -- NASA GSFC APOD
January 27, 2005: NASA sends first Genesis early-science sample to researchers -- NASA HQ
October 6, 2004: An overview of cosmic-ray elemental compositions -- ACE News
July 28, 2004: Sun spikes: Solar quakes fuel hot tendrils -- Space.com
July 28, 2004: Solar spicules explained -- Astronomy.com
April 6, 2004: Solar wind sampler seals its scoops -- New Scientist
April 5, 2004: No variability of N/O in the solar wind implies non-solar origin of lunar nitrogen -- ACE News
April 5, 2004: NASA spacecraft locks the vault on its sapphire, diamond payload -- NASA JPL
April 2, 2004: Here comes the Sun -- SpaceDaily
November 11, 2003: Solar flare 'reproduced' in lab -- BBC News
October 15, 2003: Revised periodic table slanted toward astronomers -- ScienceDaily
September 11, 2003: Sudbury Neutrino Observatory reports new measurements - thanks to table salt! -- ScienceDaily
June 19, 2003: "Dark side" of the Universe is coming to light -- National Geographic
April 12, 2003: Mapping the 'cosmic web' of dark matter -- Spaceflight Now
April 3, 2003: How the Sun shines -- Space.com
March 19, 2003: New telescope is upside-down at the bottom of the sea -- Space.com
January 28, 2003: South Pole telescope follows trail of neutrinos -- Spaceflight Now
January 17, 2003: What is the solar neutrino problem? -- NASA GSFC Science Question of the Week
January 1, 2003: Looking forward to physics at Tevatron Run II -- CERN
December 6, 2002: Sun is ok, says latest neutrino experiment -- Eurekalert
December 4, 2002: Researchers make first images of Earth's plasma sheet, discover possible breakthrough for monitoring and predicting space weather -- NASA GSFC
December 13, 2002: What carries more kinetic energy than a Randy Johnson fastball, yet is only the size of an atom? -- NASA GSFC Science Question of the Week
November 1, 2002: Detecting dark dimensions -- Physical Review Focus
October 29, 2002: Researchers get first look into antimatter atoms -- NSF
October 29, 2002: Researchers get first look into antimatter atoms -- SpaceRef.com
October 23, 2002: Gamma-ray telescope to sleuth for origin of elements -- NASA GSFC
September 20, 2002: Antimatter breakthrough: Big batch created in lab -- National Geographic
September 16, 2002: Nuclei reveal novel decay -- PhysicsWeb
September 1, 2002: Particle physics: A world without borders -- CERN Courier
July 17, 2002: Element 118 dropped from periodic table -- Scientific American
April 23, 2002: When neutrinos change type, some must have mass -- UniSci
April 22, 2002: Experiment confirms Sun theories -- BBC
April 22, 2002: Solar neutrinos really do change -- Berkeley Lab
April 11, 2002: Neutrinos from the Sun and from a factory described -- UniSci
April 10, 2002: Cosmic X-rays reveal evidence for new form of matter -- NASA HQ
March 20, 2002: A new form of matter -- Science@NASA
February 1, 2002: The Standard Model in trouble? -- Jupiter Scientific
January 22, 2002: Neutron bounce quantized in Earth gravity -- NASA GSFC APOD
October 30, 2001: Plucky IMP completes 28-year observing marathon -- NASA HQ
October 29, 2001: Plasma physics meeting this week one of the largest -- UniSci
June 27, 2001: Cluster's whispers probe the electrifying plasmasphere -- Spaceflight Now
June 26, 2001: Cluster's whispers probe the electrifying plasmasphere -- Spacer.com
June 20, 2001: Solar neutrino problem solved -- Spaceflight Now
October 1, 2000: "God particle" possibly discovered -- Jupiter Scientific
July 20, 2000: Science finds particle perfection -- BBC News
September 7, 1999: Plasma, plasma, everywhere -- NASA MSFC
February 22, 1999: New electron states observed by Caltech physicists -- Caltech
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