Cosmic Rays

The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe.
Philip W. Anderson

Cosmic Rays in the News
Cosmic Ray Activities

Particles that bombard the Earth from anywhere beyond its atmosphere are known as cosmic rays. Cosmic rays don't take pretty pictures, but studying the quantity and type of these particles helps us to understand the acceleration processes involved and to measure the composition of the Sun, as well as sources at the far distant reaches of the galaxy.

Cosmic rays include:

Galactic Cosmic Rays -- coming from outside the solar system
Anomalous Cosmic Rays -- coming from the interstellar space at the edge of the heliopause
Solar Energetic Particles -- associated with solar flares and other energetic solar events
The term "cosmic rays" used to include X-rays and gamma rays, which are well covered in Imagine the Universe! (http://imagine.gsfc.nasa.gov) (See Disc1)

The relative numbers of different isotopes found in the galaxy are established by the life cycle of massive stars. Star formation, evolution and explosion results in the creation of many of the heavier isotopes found in space. The process is shown in the figure below.

Nucleosynthesis in massive stars - diagram

This stellar evolution image is courtesy of Drs. R. Mewaldt, E. Stone, and M. Wiedenbeck of the California Institute of Technology (Caltech).

In a part of the galaxy where the composition of the interstellar gas is much like that of our own solar system (a), a cloud of gas collapses under the influence of its own gravity, and creates a new star (b). Inside the star (c), fusion converts some of the original hydrogen and helium into particles like carbon-12 and oxygen-16. At the same time, the carbon, nitrogen, and oxygen nuclei that were originally present in the star's fuel are converted into heavier, neutron-rich nuclei, like neon-22 and magnesium-25.

When this burning has exhausted all of the nuclear fuel in the core of the star, the star explodes as a supernova (d). The shock wave generated by the explosion produces additional heavy nuclei and ejects most of these products of nucleosynthesis back into the interstellar gas.

Repetition of these events in each generation of stars steadily enriches the interstellar gas in carbon, nitrogen, and oxygen, and in heavy nuclei with an excess of neutrons.

Some of the nuclei in the gas are accelerated to cosmic ray speeds, possibly by the shock waves from supernovae (e). Cosmic ray acceleration could also occur directly as the supernova is ejecting matter into interstellar space, as in (d).

To learn a lot more about cosmic rays, energetic particles, and plasma, check out our question and answer page on cosmic rays in our "Ask Us" feature.

Even more about cosmic rays:

What are cosmic rays? (http://imagine.gsfc.nasa.gov/docs/science/know_l1/cosmic_rays.html) (See Disc1) -- NASA GSFC "Imagine the Universe!"
Cosmic Rays (http://phy6.org/Education/wcosray.html) -- Exploration of the Earth's Magnetosphere
Cosmic Rays (http://www.srl.caltech.edu/personnel/dick/cos_encyc.html) -- R.A. Mewaldt, Caltech

More about the interstellar medium:

From the ACE mission (http://www-ssg.sr.unh.edu/ism/) -- University of New Hampshire

Cosmic Rays in the News:

August 14, 2006: Cosmic rays -- NASA GSFC APOD
July 1, 2006: ALICE experiment sees first cosmic-ray events (http://www.cerncourier.com/main/article/46/6/5) -- CERN Courier
March 20, 2006: Resisting radiation (http://www.astrobio.net/news/modules.php?op="modload&name=News&file=article&sid=1901&mode=thread&order=0&thold=0) -- Astrobiology Magazine
March 1, 2006: Germany seeks to fulfil astroparticle aspirations (http://www.cerncourier.com/main/article/46/2/16) -- CERN Courier
November 18, 2005: Radiation resistant computers (http://science.nasa.gov/headlines/y2005/18nov_eaftc.htm) -- Science@NASA
October 9, 2005: Who's afraid of a solar flare? (http://www.spacedaily.com/news/solarscience-05zf.html) -- SpaceDaily
October 7, 2005: St. Jude Medical discovers cosmic radiation can affect memory chip in limited number of older generation ICDs (http://phx.corporate-ir.net/test/phoenix.zhtml?c="73836&p=IROL-SingleRelease_print&t=NewsRelease&id=765369&highlight=) -- St. Jude Medical News
September 27, 2005: Voyager finds three surprises near our solar system's edge (http://www.physorg.com/news6788.html) -- PhysOrg.com
September 26, 2005: Voyager 1: messages from the edge (http://www.spaceref.com/news/viewpr.html?pid="17883) -- SpaceRef.com
September 8, 2005: Radioactive Moon (http://science.nasa.gov/headlines/y2005/08sep_radioactivemoon.htm) -- Science@NASA
August 8, 2005: Cosmic rays 'harm pilots' sight' (http://news.bbc.co.uk/1/hi/health/4131232.stm) -- BBC News
July 24, 2004: Did cosmic rays cause ice ages? (http://physicsweb.org/article/news/8/7/6) -- PhysicsWeb
March 18, 2004: Space dust to unlock pyramid secrets (http://www.abc.net.au/science/news/space/SpaceRepublish_1068315.htm) -- Australian Broadcasting Corporation
January 21, 2004: Cosmic rays are not the cause of climate change, scientists say (http://www.agu.org/sci_soc/prrl/prrl0405.html) -- AGU News
December 2, 2003: Solar activity reaches new high (http://www.physicsweb.org/article/news/7/12/2) -- PhysicsWeb
November 14, 2003: Fireballs from space (http://www.sciencentral.com/articles/view.php3?language="english&type=article&article_id=218392108) -- ScienCentral
October 23, 2003: New study seeks to identify and minimize danger to aviation from cosmic radiation (http://www.sciencedaily.com/releases/2003/10/031023070915.htm) -- ScienceDaily
October 14, 2003: New NASA facility will help protect space crews from radiation (http://www.spaceref.com/news/viewpr.html?pid="12776) -- SpaceRef.com
October 14, 2003: NASA and DOE dedicate new NASA facility at Brookhaven Lab (http://www.bnl.gov/bnlweb/pubaf/pr/2003/bnlpr101403.htm) -- Brookhaven National Laboratory
August 14, 2003: MINOS detector ready to take first data (http://www.eurekalert.org/pub_releases/2003-08/ppa-mdr081403.php) -- EurekAlert
July 4, 2003: Debating the Sun's effect on climate (http://news.bbc.co.uk/1/hi/sci/tech/3036032.stm) -- BBC News
May 1, 2003: Muons bend to beat the smuggler (http://www.cerncourier.com/main/article/43/4/6) -- CERN Courier
April 5, 2003: Galactic wind of low-energy cosmic rays claimed (http://www.spaceflightnow.com/news/n0304/06cosmic/) -- Spaceflight Now
March 27, 2003: Is the Earth preparing to flip? (http://news.bbc.co.uk/1/hi/sci/tech/2889127.stm) -- BBC News
March 27, 2003: The Core: Hollywood fiction or science? (http://news.nationalgeographic.com/news/2003/03/0327_030327_tvcore.html) -- National Geographic
March 20, 2003: NASA selects next medium-class Explorer mission (http://www.nasa.gov/home/hqnews/2003/mar/HP_news_c03h.html) -- NASA
March 19, 2003: Cosmic particles could detect nuke materials, scientists say (http://news.nationalgeographic.com/news/2003/03/0319_030319_cosmicrays.html) -- National Geographic
March 19, 2003: Cosmic rays could catch nuclear smugglers (http://www.newscientist.com/news/news.jsp?id="ns99993526) -- New Scientist
March 15, 2003: NASA's Odyssey marks one year in orbit around Mars (http://www.spaceflightnow.com/news/n0303/15mars/) -- Spaceflight Now
March 14, 2003: Can events on the Sun be a hazard to airline flights? (http://www.gsfc.nasa.gov/scienceques2002/20030314.htm) -- NASA GSFC
February 25, 2003: Pioneer 10 spacecraft sends last signal (http://www.nasa.gov/home/hqnews/2003/feb/HP_news_03082.html) -- NASA
February 16, 2003: Auger experiment could resolve mystery of high-energy cosmic rays (http://www-news.uchicago.edu/releases/03/030216.rays.shtml) -- University of Chicago
January 31, 2003: America marks 45th anniversary of first space satellite (http://www.spaceref.com/news/viewnews.html?id="721) -- SpaceRef.com
January 31, 2003: Nation's first space "gem" marks sapphire anniversary (ftp://ftp.hq.nasa.gov/pub/pao/pressrel/2003/03-029.txt) --NASA HQ
January 15, 2003: Early cosmic-ray research in Argentina (http://www.physicstoday.org/vol-56/iss-1/p32.html) -- Physics Today
January 8, 2003: Earth likely spared from one form of cosmic doom (http://www.gsfc.nasa.gov/topstory/2003/0108supernova.html) -- NASA GSFC
January 6, 2003: Near-Earth supernovas (http://science.nasa.gov/headlines/y2003/06jan_bubble.htm?list847478) -- Science@NASA
December 30, 2002: More to physics than meets the eye (http://www.cerncourier.com/main/article/42/9/19) -- CERN Courier
December 13, 2002: What carries more kinetic energy than a Randy Johnson fastball, yet is only the size of an atom? (http://www.gsfc.nasa.gov/scienceques2002/20021213.htm) -- NASA GSFC Science Question of the Week
November 26, 2002: Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) satellite (http://www.gsfc.nasa.gov/topstory/2002/1217chips.html) -- NASA GSFC
October 1, 2002: PAMELA set to take particle physics into orbit (http://www.cerncourier.com/main/article/42/8/17) -- CERN Courier
August 9, 2002: Balloon above Canada searches for antimatter and other cosmic particles (http://www.gsfc.nasa.gov/news-release/releases/2002/02-123.htm) -- NASA GSFC
May 8, 2002: Guinness names aerogel world's lightest solid (http://www.spaceflightnow.com/news/n0205/08aerogel/) -- Spaceflight Now
March 22, 2002: Ordinary physics can't be used to study cosmic rays (http://unisci.com/stories/20021/0322022.htm) -- UniSci
March 15, 2002: Neutron Mars (http://antwrp.gsfc.nasa.gov/apod/ap020315.html) -- NASA GSFC APOD
March 15, 2002: Measuring Martian radiation: Good and bad news (http://skyandtelescope.com/news/current/article_535_1.asp) -- Sky & Telescope
March 1, 2002: NASA to attempt contact with Pioneer 10 spacecraft (http://www.spaceflightnow.com/news/n0203/01pioneer10/) -- Spaceflight Now
February 25, 2002: Cold antihydrogen atoms may have been made at CERN (http://unisci.com/stories/20021/0225023.htm) -- UniSci
November 22, 2001: Dartmouth researcher uses cosmic rays to calculate erosion rates (http://www.sciencedaily.com/releases/2001/11/011120052740.htm) -- Dartmouth University
November 13, 2001: Old 'surfatron' concept might apply to cosmic rays (http://unisci.com/stories/20014/1113016.htm) -- UniSci
November 12, 2001: Milky Way may harbor high-energy cosmic ray sources (http://unisci.com/stories/20014/1112011.htm) -- UniSci
November 1, 2001: Astroparticle physicists gain increased support (http://www.cerncourier.com/main/article/41/9/15) -- Cern Courier
August 13, 2001: Ozone layer burned by cosmic rays (http://focus.aps.org/story/v8/st8) -- Physical Review Focus
August 1, 2001: Cosmic rays linked to ozone hole (http://www.newscientist.com/news/news.jsp?id="ns99991121) -- New Scientist
June 29, 2001: Energetic particle fluences from solar wind to cosmic ray energies (http://www.srl.caltech.edu/ACE/ACENews/ACENews54.html) -- ACE News
March 5, 2001: Return of the flying bird (http://heasarc.gsfc.nasa.gov/docs/objects/heapow/archive/technology/asca_mission.html) -- NASA GSFC HEAPOW
February 19, 2001: Why so little antimatter? Physicists just don't know (http://unisci.com/stories/20011/0219014.htm) -- UniSci
November 25, 2000: A high energy fleet (http://antwrp.gsfc.nasa.gov/apod/ap001125.html) -- NASA GSFC APOD
September 3, 2000: Intriguing meteorite discovered in Saskatchewan (http://spaceflightnow.com/news/n0009/03sackmeteorite/) -- Spaceflight Now
June 15, 2000: Officials seek to extend Ulysses sun probe mission (http://spaceflightnow.com/news/n0006/15ulyssesextend/index.html) -- Spaceflight Now
June 8, 2000: Astronomers discover origin of light elements (http://space.com/scienceastronomy/astronomy/light_elements_000608.html) -- Space.com
April 19, 2000: Cosmic rays will reveal universal secrets (http://news.bbc.co.uk/hi/english/sci/tech/newsid_719000/719514.stm) -- BBC News
January 7, 2000: NAUTILUS detects cosmic rays (http://physicsweb.org/article/news/4/1/2) -- PhysicsWeb
November 29, 1999: ACCESS intercepts cosmic rays (http://cerncourier.com/main/article/39/10/8/1) -- CERN Courier
November 9, 1998: New method of dating past earthquakes, assessing future ones discovered (http://www.sciencedaily.com/releases/1998/11/981109082823.htm) -- ScienceDaily
October 23, 1998: Ancient cosmic rays captured by powerful magnet on the edge of space (http://lheawww.gsfc.nasa.gov/docs/gamcosray/hecr/ISOMAX/release.html) -- NASA Goddard News
July 2, 1998: CRIS data indicate a long delay between nucleosynthesis and cosmic ray acceleration (http://www.srl.caltech.edu/ACE/ACENews/ACENews17.html) -- ACE News
January 1997: Cosmic rays at the energy frontier (http://auger.cnrs.fr/presse/ScAm_jan97.html) -- Scientific American

Cosmic Ray Activities:

Grades 7 - 12: In Search of Cosmic Rays: Investigations into the Origin of Cosmic Rays (http://sunshine.chpc.utah.edu/javalabs/java102/hess/index.htm) - 5 activities -- University of Utah ASPIRE Project

BASICS .. COSMIC RAYS .. SUN .. SPACE WEATHER

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